Find, fix and prevent vulnerabilities in your code.
high severity
- Vulnerable module: redcarpet
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › redcarpet@2.3.0Remediation: Upgrade to jekyll@2.0.0.
Overview
Affected versions of this package are vulnerable to Cross-site Scripting (XSS). This happens because no HTML escaping is being performed when processing quotes. This applies even when the :escape_html
option was being used in combination with :quote
.
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 redcarpet
to version 3.5.1 or higher.
References
high severity
- Vulnerable module: redcarpet
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › redcarpet@2.3.0Remediation: Upgrade to jekyll@2.0.0.
Overview
redcarpet
is a Markdown to (X)HTML parser.
Affected versions of this package are vulnerable to Cross-site Scripting via the parse_inline()
function in markdown.c does not validate input before returning it to users. This may allow a remote attacker to create a specially crafted request that would execute arbitrary script code in a user's browser session within the trust relationship between their browser and the server.
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.
References
high severity
- Vulnerable module: ffi
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › listen@1.3.1 › rb-inotify@0.9.2 › ffi@1.9.3Remediation: Upgrade to jekyll@1.3.0.
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › listen@1.3.1 › rb-kqueue@0.2.0 › ffi@1.9.3Remediation: Upgrade to jekyll@1.3.0.
Overview
ffi is a ruby extension for programmatically loading dynamic libraries, binding functions within them, and calling those functions from Ruby code.
Affected versions of this package are vulnerable to DLL Loading Issue on Windows OS, when a Symbol is used as DLL name instead of a String.
Remediation
Upgrade ffi
to version 1.9.24 or higher.
References
high severity
- Vulnerable module: jekyll
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0Remediation: Upgrade to jekyll@3.6.3.
Overview
jekyll is a web framework for building static websites.
Affected versions of this package are vulnerable to Improper Access Control. This allows attackers to access arbitrary files by specifying a symlink in the include
key in the _config.yml
file.
Remediation
Upgrade jekyll
to version 3.6.3, 3.7.4, 3.8.4 or higher.
References
high severity
- Vulnerable module: yajl-ruby
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › pygments.rb@0.5.4 › yajl-ruby@1.1.0Remediation: Upgrade to jekyll@3.0.0.
Overview
yajl-ruby
Ruby C bindings to the excellent Yajl JSON stream-based parser library.
Affected versions of this project are vulnerable to Denial of Service (DoS) attacks. When a crafted JSON file is supplied to Yajl::Parser.new.parse
, the whole ruby process crashes with a SIGABRT in the yajl_string_decode
function in yajl_encode.c
. This results in the whole ruby process terminating and potentially a denial of service.
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 yajl-ruby
to version 1.3.1 or higher.
References
medium severity
- Vulnerable module: liquid
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › liquid@2.5.4Remediation: Upgrade to jekyll@1.3.0.
Overview
liquid
is a secure, non-evaling end user template engine with aesthetic markup.
Affected versions of the package are vulnerable to Arbitrary Method Invocation on a Condition object via the if
tag.
Remediation
Upgrade liquid
to version 2.5.5, 2.6.1 or higher.
References
medium severity
- Vulnerable module: yajl-ruby
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › pygments.rb@0.5.4 › yajl-ruby@1.1.0Remediation: Upgrade to jekyll@3.0.0.
Overview
Affected versions of this package are vulnerable to Denial of Service (DoS) due to an integer overflow which leads to subsequent heap memory corruption when dealing with large (~2GB) inputs.
The reallocation logic at yajl_buf.c#L64
may result in the need
32bit integer wrapping to 0 when need
approaches a value of 0x80000000 (i.e. ~2GB of data), which results in a reallocation of buf->alloc into a small heap chunk.
Note:
If upgrading to the fixed version is not possible, avoid passing large inputs to YAJL As a workaround.
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 yajl-ruby
to version 1.4.2 or higher.
References
medium severity
- Vulnerable module: jekyll
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0Remediation: Upgrade to jekyll@1.4.3.
Overview
jekyll
is a simple, blog aware, static site generator.
Affected versions of the package are vulnerable to Arbitrary File Read by placing a symlink to a directory in _includes
.
Remediation
Upgrade jekyll
to version 1.4.3 or higher.
References
medium severity
- Vulnerable module: jekyll
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0Remediation: Upgrade to jekyll@1.4.3.
Overview
jekyll
is a simple, blog aware, static site generator.
Affected versions of the package are vulnerable to Directory Traversal.
Details
A Directory Traversal attack (also known as path traversal) aims to access files and directories that are stored outside the intended folder. By manipulating files with "dot-dot-slash (../)" sequences and its variations, or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system, including application source code, configuration, and other critical system files.
Directory Traversal vulnerabilities can be generally divided into two types:
- Information Disclosure: Allows the attacker to gain information about the folder structure or read the contents of sensitive files on the system.
st
is a module for serving static files on web pages, and contains a vulnerability of this type. In our example, we will serve files from the public
route.
If an attacker requests the following URL from our server, it will in turn leak the sensitive private key of the root user.
curl http://localhost:8080/public/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/root/.ssh/id_rsa
Note %2e
is the URL encoded version of .
(dot).
- Writing arbitrary files: Allows the attacker to create or replace existing files. This type of vulnerability is also known as
Zip-Slip
.
One way to achieve this is by using a malicious zip
archive that holds path traversal filenames. When each filename in the zip archive gets concatenated to the target extraction folder, without validation, the final path ends up outside of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.
The following is an example of a zip
archive with one benign file and one malicious file. Extracting the malicious file will result in traversing out of the target folder, ending up in /root/.ssh/
overwriting the authorized_keys
file:
2018-04-15 22:04:29 ..... 19 19 good.txt
2018-04-15 22:04:42 ..... 20 20 ../../../../../../root/.ssh/authorized_keys
Remediation
Upgrade jekyll
to version 1.4.3 or higher.
References
medium severity
- Vulnerable module: liquid
- Introduced through: jekyll@1.3.0
Detailed paths
-
Introduced through: bangaloreruby/bangaloreruby.github.com@bangaloreruby/bangaloreruby.github.com#431d1eac681dd5952b16ca63e72c003d7417c94f › jekyll@1.3.0 › liquid@2.5.4Remediation: Upgrade to jekyll@1.3.0.
Overview
liquid
is a secure, non-evaling end user template engine with aesthetic markup.
Affected versions of the package are vulnerable to Denial of Service (DoS).
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 liquid
to version 2.5.5, 2.6.1 or higher.