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Critical Jenkins Vulnerability Exposes Servers to RCE Attacks - Patch ASAP!
The maintainers of the open-source continuous integration/continuous delivery and deployment (CI/CD) automation software Jenkins have resolved nine security flaws, including a critical bug that, if successfully exploited, could result in remote code execution (RCE). The issue, assigned the CVE identifier CVE-2024-23897, has been described as an arbitrary file read vulnerability through the
Vulnerability / Software Security
The maintainers of the open-source continuous integration/continuous delivery and deployment (CI/CD) automation software Jenkins have resolved nine security flaws, including a critical bug that, if successfully exploited, could result in remote code execution (RCE).
The issue, assigned the CVE identifier CVE-2024-23897, has been described as an arbitrary file read vulnerability through the built-in command line interface (CLI)
“Jenkins uses the args4j library to parse command arguments and options on the Jenkins controller when processing CLI commands,” the maintainers said in a Wednesday advisory.
“This command parser has a feature that replaces an @ character followed by a file path in an argument with the file’s contents (expandAtFiles). This feature is enabled by default and Jenkins 2.441 and earlier, LTS 2.426.2 and earlier does not disable it.”
A threat actor could exploit this quirk to read arbitrary files on the Jenkins controller file system using the default character encoding of the Jenkins controller process.
While attackers with “Overall/Read” permission can read entire files, those without it can read the first three lines of the files depending on the CLI commands.
Additionally, the shortcoming could be weaponized to read binary files containing cryptographic keys, albeit with certain restrictions. Provided the binary secrets can be extracted, Jenkins says it could open the door to various attacks -
- Remote code execution via Resource Root URLs
- Remote code execution via “Remember me” cookie
- Remote code execution via stored cross-site scripting (XSS) attacks through build logs
- Remote code execution via CSRF protection bypass
- Decrypt secrets stored in Jenkins
- Delete any item in Jenkins
- Download a Java heap dump
“While files containing binary data can be read, the affected feature attempts to read them as strings using the controller process’s default character encoding,” Jenkins said.
“This is likely to result in some bytes not being read successfully and being replaced with a placeholder value. Which bytes can or cannot be read depends on this character encoding.”
Security researcher Yaniv Nizry has been credited with discovering and reporting the flaw, which has been fixed in Jenkins 2.442, LTS 2.426.3 by disabling the command parser feature.
As a short-term workaround until the patch can be applied, it’s recommended to turn off access to the CLI.
The development comes nearly a year after Jenkins addressed a pair of severe security vulnerabilities dubbed CorePlague (CVE-2023-27898 and CVE-2023-27905) that could lead to code execution on targeted systems.
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Jenkins has a built-in command line interface (CLI) to access Jenkins from a script or shell environment. Jenkins uses the args4j library to parse command arguments and options on the Jenkins controller when processing CLI commands. This command parser has a feature that replaces an @ character followed by a file path in an argument with the file’s contents (expandAtFiles). This feature is enabled by default and Jenkins 2.441 and earlier, LTS 2.426.2 and earlier does not disable it. This allows attackers to read arbitrary files on the Jenkins controller file system using the default character encoding of the Jenkins controller process. * Attackers with Overall/Read permission can read entire files. * Attackers without Overall/Read permission can read the first few lines of files. The number of lines that can be read depends on available CLI commands. As of publication of this advisory, the Jenkins security team has found ways to read the first three lines of files in recent relea...
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Jenkins update-center2 3.13 and 3.14 renders the required Jenkins core version on plugin download index pages without sanitization, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to provide a plugin for hosting.
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Jenkins 2.393 and earlier, LTS 2.375.3 and earlier prints an error stack trace on agent-related pages when agent connections are broken, potentially revealing information about Jenkins configuration that is otherwise inaccessible to attackers.
Jenkins 2.270 through 2.393 (both inclusive), LTS 2.277.1 through 2.375.3 (both inclusive) does not escape the Jenkins version a plugin depends on when rendering the error message stating its incompatibility with the current version of Jenkins, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to provide plugins to the configured update sites and have this message shown by Jenkins instances.
Jenkins 2.270 through 2.393 (both inclusive), LTS 2.277.1 through 2.375.3 (both inclusive) does not escape the Jenkins version a plugin depends on when rendering the error message stating its incompatibility with the current version of Jenkins, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to provide plugins to the configured update sites and have this message shown by Jenkins instances.
Jenkins 2.393 and earlier, LTS 2.375.3 and earlier shows temporary directories related to job workspaces, which allows attackers with Item/Workspace permission to access their contents.
Jenkins 2.393 and earlier, LTS 2.375.3 and earlier prints an error stack trace on agent-related pages when agent connections are broken, potentially revealing information about Jenkins configuration that is otherwise inaccessible to attackers.
A pair of severe security vulnerabilities have been disclosed in the Jenkins open source automation server that could lead to code execution on targeted systems. The flaws, tracked as CVE-2023-27898 and CVE-2023-27905, impact the Jenkins server and Update Center, and have been collectively christened CorePlague by cloud security firm Aqua. All versions of Jenkins versions prior to 2.319.2 are
A pair of severe security vulnerabilities have been disclosed in the Jenkins open source automation server that could lead to code execution on targeted systems. The flaws, tracked as CVE-2023-27898 and CVE-2023-27905, impact the Jenkins server and Update Center, and have been collectively christened CorePlague by cloud security firm Aqua. All versions of Jenkins versions prior to 2.319.2 are