ejs@0.8.8

Vulnerabilities

4 via 4 paths

Dependencies

Source

npm

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Severity
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Status
  • 4
  • 0
  • 0

high severity

Arbitrary Code Execution

  • Vulnerable module: ejs
  • Introduced through: ejs@0.8.8

Detailed paths

  • Introduced through: ejs@0.8.8
    Remediation: Upgrade to ejs@2.5.3.

Overview

ejs is a popular JavaScript templating engine. Affected versions of the package are vulnerable to Remote Code Execution by letting the attacker under certain conditions control the source folder from which the engine renders include files. You can read more about this vulnerability on the Snyk blog.

There's also a Cross-site Scripting & Denial of Service vulnerabilities caused by the same behaviour.

Details

ejs provides a few different options for you to render a template, two being very similar: ejs.render() and ejs.renderFile(). The only difference being that render expects a string to be used for the template and renderFile expects a path to a template file.

Both functions can be invoked in two ways. The first is calling them with template, data, and options:

ejs.render(str, data, options);

ejs.renderFile(filename, data, options, callback)

The second way would be by calling only the template and data, while ejs lets the options be passed as part of the data:

ejs.render(str, dataAndOptions);

ejs.renderFile(filename, dataAndOptions, callback)

If used with a variable list supplied by the user (e.g. by reading it from the URI with qs or equivalent), an attacker can control ejs options. This includes the root option, which allows changing the project root for includes with an absolute path.

ejs.renderFile('my-template', {root:'/bad/root/'}, callback);

By passing along the root directive in the line above, any includes would now be pulled from /bad/root instead of the path intended. This allows the attacker to take control of the root directory for included scripts and divert it to a library under his control, thus leading to remote code execution.

The fix introduced in version 2.5.3 blacklisted root options from options passed via the data object.

Disclosure Timeline

  • November 27th, 2016 - Reported the issue to package owner.
  • November 27th, 2016 - Issue acknowledged by package owner.
  • November 28th, 2016 - Issue fixed and version 2.5.3 released.

Remediation

The vulnerability can be resolved by either using the GitHub integration to generate a pull-request from your dashboard or by running snyk wizard from the command-line interface. Otherwise, Upgrade ejs to version 2.5.3 or higher.

References

medium severity

Arbitrary Code Injection

  • Vulnerable module: ejs
  • Introduced through: ejs@0.8.8

Detailed paths

  • Introduced through: ejs@0.8.8
    Remediation: Upgrade to ejs@3.1.6.

Overview

ejs is a popular JavaScript templating engine.

Affected versions of this package are vulnerable to Arbitrary Code Injection via the render and renderFile. If external input is flowing into the options parameter, an attacker is able run arbitrary code. This include the filename, compileDebug, and client option.

POC

let ejs = require('ejs')
ejs.render('./views/test.ejs',{
    filename:'/etc/passwd\nfinally { this.global.process.mainModule.require(\'child_process\').execSync(\'touch EJS_HACKED\') }',
    compileDebug: true,
    message: 'test',
    client: true
})

Remediation

Upgrade ejs to version 3.1.6 or higher.

References

medium severity

Cross-site Scripting (XSS)

  • Vulnerable module: ejs
  • Introduced through: ejs@0.8.8

Detailed paths

  • Introduced through: ejs@0.8.8
    Remediation: Upgrade to ejs@2.5.5.

Overview

ejs is a popular JavaScript templating engine. Affected versions of the package are vulnerable to Cross-site Scripting by letting the attacker under certain conditions control and override the filename option causing it to render the value as is, without escaping it. You can read more about this vulnerability on the Snyk blog.

There's also a Remote Code Execution & Denial of Service vulnerabilities caused by the same behaviour.

Details

ejs provides a few different options for you to render a template, two being very similar: ejs.render() and ejs.renderFile(). The only difference being that render expects a string to be used for the template and renderFile expects a path to a template file.

Both functions can be invoked in two ways. The first is calling them with template, data, and options:

ejs.render(str, data, options);

ejs.renderFile(filename, data, options, callback)

The second way would be by calling only the template and data, while ejs lets the options be passed as part of the data:

ejs.render(str, dataAndOptions);

ejs.renderFile(filename, dataAndOptions, callback)

If used with a variable list supplied by the user (e.g. by reading it from the URI with qs or equivalent), an attacker can control ejs options. This includes the filename option, which will be rendered as is when an error occurs during rendering.

ejs.renderFile('my-template', {filename:'<script>alert(1)</script>'}, callback);

The fix introduced in version 2.5.3 blacklisted root options from options passed via the data object.

Disclosure Timeline

  • November 28th, 2016 - Reported the issue to package owner.
  • November 28th, 2016 - Issue acknowledged by package owner.
  • December 06th, 2016 - Issue fixed and version 2.5.5 released.

Remediation

The vulnerability can be resolved by either using the GitHub integration to generate a pull-request from your dashboard or by running snyk wizard from the command-line interface. Otherwise, Upgrade ejs to version 2.5.5 or higher.

References

medium severity

Denial of Service (DoS)

  • Vulnerable module: ejs
  • Introduced through: ejs@0.8.8

Detailed paths

  • Introduced through: ejs@0.8.8
    Remediation: Upgrade to ejs@2.5.5.

Overview

ejs is a popular JavaScript templating engine. Affected versions of the package are vulnerable to Denial of Service by letting the attacker under certain conditions control and override the localNames option causing it to crash. You can read more about this vulnerability on the Snyk blog.

There's also a Remote Code Execution & Cross-site Scripting vulnerabilities caused by the same behaviour.

Details

ejs provides a few different options for you to render a template, two being very similar: ejs.render() and ejs.renderFile(). The only difference being that render expects a string to be used for the template and renderFile expects a path to a template file.

Both functions can be invoked in two ways. The first is calling them with template, data, and options:

ejs.render(str, data, options);

ejs.renderFile(filename, data, options, callback)

The second way would be by calling only the template and data, while ejs lets the options be passed as part of the data:

ejs.render(str, dataAndOptions);

ejs.renderFile(filename, dataAndOptions, callback)

If used with a variable list supplied by the user (e.g. by reading it from the URI with qs or equivalent), an attacker can control ejs options. This includes the localNames option, which will cause the renderer to crash.

ejs.renderFile('my-template', {localNames:'try'}, callback);

The fix introduced in version 2.5.3 blacklisted root options from options passed via the data object.

Disclosure Timeline

  • November 28th, 2016 - Reported the issue to package owner.
  • November 28th, 2016 - Issue acknowledged by package owner.
  • December 06th, 2016 - Issue fixed and version 2.5.5 released.

Remediation

The vulnerability can be resolved by either using the GitHub integration to generate a pull-request from your dashboard or by running snyk wizard from the command-line interface. Otherwise, Upgrade ejs to version 2.5.5 or higher.

References