GHSA-h856-ffvv-xvr4 BIT-jenkins-2024-43044 CVE-2024-43044
Jenkins Remoting library arbitrary file read vulnerability
High
Maven
- Severity
- 0.0 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 28.78%
- Chance of exploitation in the next 30 days. Higher than 98.15% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
- CWE-754 Improper Check for Unusual or Exceptional Conditions
- Fix
- Available
- 2 packages have a fixed version
Description
Jenkins uses the Remoting library (typically agent.jar or remoting.jar) for the communication between controller and agents. This library allows agents to load classes and classloader resources from the controller, so that Java objects sent from the controller (build steps, etc.) can be executed on agents.
In addition to individual class and resource files, Remoting also allows Jenkins plugins to transmit entire jar files to agents using the Channel#preloadJar API. As of publication of this advisory, this feature is used by the following plugins distributed by the Jenkins project: bouncycastle API, Groovy, Ivy, TeamConcert
In Remoting 3256.v88a_f6e922152 and earlier, except 3206.3208.v409508a_675ff and 3248.3250.v3277a_8e88c9b_, included in Jenkins 2.470 and earlier, LTS 2.452.3 and earlier, calls to Channel#preloadJar result in the retrieval of files from the controller by the agent using ClassLoaderProxy#fetchJar. Additionally, the implementation of ClassLoaderProxy#fetchJar invoked on the controller does not restrict paths that agents could request to read from the controller file system.
This allows agent processes, code running on agents, and attackers with Agent/Connect permission to read arbitrary files from the Jenkins controller file system.
The Remoting library in Jenkins 2.471, LTS 2.452.4, LTS 2.462.1 now sends jar file contents with Channel#preloadJar requests, the only use case of ClassLoaderProxy#fetchJar in agents, so that agents do not need to request jar file contents from controllers anymore.
To retain compatibility with older versions of Remoting in combination with the plugins listed above, ClassLoaderProxy#fetchJar is retained and otherwise unused, just deprecated. Its implementation in Jenkins 2.471, LTS 2.452.4, LTS 2.462.1 was changed so that it is now limited to retrieving jar files referenced in the core classloader or any plugin classloader.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.jenkins-ci.main:jenkins-core | < 2.452.4 |
2.452.4 |
| org.jenkins-ci.main:jenkins-core | >= 2.460, < 2.462.1 |
2.462.1 |
| org.jenkins-ci.main:jenkins-core | >= 2.470, < 2.471 |
2.471 |
| org.jenkins-ci.main:remoting | < 3206.3208 |
3206.3208 |
| org.jenkins-ci.main:remoting | >= 3248, < 3248.3250 |
3248.3250 |
| org.jenkins-ci.main:remoting | >= 3256, < 3256.3258 |
3256.3258 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
org.jenkins-ci.main:jenkins-core Maven → 2.452.4
- maven
<dependency><groupId>org.jenkins-ci.main</groupId><artifactId>jenkins-core</artifactId><version>2.452.4</version></dependency>- gradle
implementation("org.jenkins-ci.main:jenkins-core:2.452.4")
org.jenkins-ci.main:remoting Maven → 3206.3208
- maven
<dependency><groupId>org.jenkins-ci.main</groupId><artifactId>remoting</artifactId><version>3206.3208</version></dependency>- gradle
implementation("org.jenkins-ci.main:remoting:3206.3208")
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- High
- Integrity (subsequent systems)
- High
- Availability (subsequent systems)
- High
CVSS 3.1 9.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How to prevent it
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would b
- Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked. Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes: realpath() in C getCanonicalPath() in Java GetFullPath() in ASP.NET realpath() or abs_path() in Perl realpath() in PHP
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
- Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
- Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
- Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.
- Architecture and Design, Operation: Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Architecture and Design, Operation: Store library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately. This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.
- Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not. In the context of path traversal, error messages which disclose path information can help attackers craft the appropriate attack strings to move through the file system hierarchy.
- Operation, Implementation: When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
CWE-754: Improper Check for Unusual or Exceptional Conditions
The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
How to prevent it
- Requirements: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Choose languages with features such as exception handling that force the programmer to anticipate unusual conditions that may generate exceptions. Custom exceptions may need to be developed to handle unusual business-logic conditions. Be careful not to pass sensitive exceptions back to the user (CWE-209, CWE-248).
- Implementation: Check the results of all functions that return a value and verify that the value is expected.
- Implementation: If using exception handling, catch and throw specific exceptions instead of overly-general exceptions (CWE-396, CWE-397). Catch and handle exceptions as locally as possible so that exceptions do not propagate too far up the call stack (CWE-705). Avoid unchecked or uncaught exceptions where feasible (CWE-248).
- Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not. Exposing additional information to a potential attacker in the context of an exceptional condition can help the attacker determine what attack vectors are most likely to succeed beyond DoS.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Architecture and Design, Implementation: If the program must fail, ensure that it fails gracefully (fails closed). There may be a temptation to simply let the program fail poorly in cases such as low memory conditions, but an attacker may be able to assert control before the software has fully exited. Alternately, an uncontrolled failure could cause cascading problems with other downstream components; for example, the program could send a signal to a downstream process so the process immediately knows that a problem has occurred and has a better chance of recovery.
- Architecture and Design: Use system limits, which should help to prevent resource exhaustion. However, the product should still handle low resource conditions since they may still occur.
References
Advisories
Packages
Other links
- github.com/jenkinsci/jenkins/commit/3f54c41b40db9e4ae7afa4209bc1ea91bb9175c0
- github.com/jenkinsci/jenkins/commit/5d26b53ad3a5cd8c4a060eef4f56d75e65ca17a5
- github.com/jenkinsci/jenkins/commit/cec49ce5d58048f66ac3fa88409a0d38dec09bf0
- github.com/jenkinsci/remoting/commit/3277a8e88c9b807b9a989bd7e9176d2ec9834e47
- github.com/jenkinsci/remoting/commit/409508a675ffc4ed9681e30bb46c8d9cb375b78c
- github.com/jenkinsci/remoting/commit/858f3c9af69d4d216b26551ea51dde6e67479bb3
- jenkins.io/security/advisory/2024-08-07
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-6f9g-cxwr-q5jr Arbitrary file read vulnerability through the Jenkins CLI can lead to RCE | Critical Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-8pqx-3rxx-f5pm Jenkins discloses project names via fingerprints | High Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-26wc-3wqp-g3rp Deserialization of Untrusted Data in Jenkins | Critical Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| CVE-2018-1000861 Deserialization of Untrusted Data in Jenkins | Critical Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-m6wv-wh8g-64xc Jenkins does not encrypt secrets from POST config.xml submissions before storing them in job configurations | Medium | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-93qh-vwrm-c5pw Jenkins: Stored XSS vulnerability in node offline cause description | Medium | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-92m7-4fpw-2wxm Jenkins: Open Redirect phishing attacks possible via "from" parameter in "Delegate to servlet container" | Medium | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-g28p-6mcc-v4rv Jenkins exposes other users' timezone and view names to users with Overall/Read permission | Medium | Also affects org.jenkins-ci.main:jenkins-core |
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