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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.3325 Jenkins Security Advisory 2021-10-06 7 October 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Jenkins (core) Git Plugin Publisher: Jenkins Operating System: Windows UNIX variants (UNIX, Linux, OSX) Impact/Access: Cross-site Scripting -- Remote with User Interaction Provide Misleading Information -- Remote with User Interaction Access Confidential Data -- Remote with User Interaction Reduced Security -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2021-21684 CVE-2021-21683 CVE-2021-21682 CVE-2014-3577 Reference: ASB-2018.0163 ESB-2017.1592 Original Bulletin: https://www.jenkins.io/security/advisory/2021-10-06/ - --------------------------BEGIN INCLUDED TEXT-------------------- Jenkins Security Advisory 2021-10-06 This advisory announces vulnerabilities in the following Jenkins deliverables: o Jenkins (core) o Git Plugin Descriptions Improper handling of equivalent directory names on Windows SECURITY-2424 / CVE-2021-21682 Jenkins stores jobs and other entities on disk using their name shown on the UI as file and folder names. On Windows, when specifying a file or folder with a trailing dot character (example.), the file or folder will be treated as if that character was not present (example). As both are legal names for jobs and other entities in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier, this could allow users with the appropriate permissions to change or replace configurations of jobs and other entities. Jenkins 2.315, LTS 2.303.2 does not allow names of jobs and other entities to end with a dot character. Jenkins core bundles vulnerable version of the commons-httpclient library SECURITY-2475 / CVE-2014-3577 Jenkins 2.314 and earlier, LTS 2.303.1 and earlier bundles a version of the commons-httpclient library with the vulnerability CVE-2014-3577 that incorrectly verified SSL/TLS certificates, making it susceptible to man-in-the-middle attacks. This library is widely used as a transitive dependency in Jenkins plugins. The fix for CVE-2014-3577 was backported to the version of commons-httpclient that is bundled in Jenkins 2.315, LTS 2.303.2 and made available to plugins. Path traversal vulnerability on Windows SECURITY-2481 / CVE-2021-21683 The file browser for workspaces, archived artifacts, and userContent/ in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier may interpret some paths to files as absolute on Windows. This results in a path traversal vulnerability allowing attackers with Overall/ Read permission (Windows controller) or Job/Workspace permission (Windows agents) to obtain the contents of arbitrary files. The file browser in Jenkins 2.315, LTS 2.303.2 refuses to serve files that would be considered absolute paths. Stored XSS vulnerability in Git Plugin SECURITY-2499 / CVE-2021-21684 Git Plugin 4.8.2 and earlier does not escape the Git SHA-1 checksum parameters provided to commit notifications when displaying them in a build cause. This results in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to submit crafted commit notifications to the /git/ notifyCommit endpoint. Git Plugin 4.8.3 rejects Git SHA-1 checksum parameters that do not match the expected format. Existing values are sanitized when displayed on the UI. Note This vulnerability is only exploitable in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier. See the LTS upgrade guide. Severity o SECURITY-2424: Medium o SECURITY-2475: Medium o SECURITY-2481: Medium o SECURITY-2499: High Affected Versions o Jenkins weekly up to and including 2.314 o Jenkins LTS up to and including 2.303.1 o Git Plugin up to and including 4.8.2 Fix o Jenkins weekly should be updated to version 2.315 o Jenkins LTS should be updated to version 2.303.2 o Git Plugin should be updated to version 4.8.3 These versions include fixes to the vulnerabilities described above. All prior versions are considered to be affected by these vulnerabilities unless otherwise indicated. Credit The Jenkins project would like to thank the reporters for discovering and reporting these vulnerabilities: o Daniel Beck, CloudBees, Inc. for SECURITY-2499 o Mumin Koykiran for SECURITY-2481 o Wadeck Follonier, CloudBees, Inc., Daniel Beck, CloudBees, Inc., and James Nord, CloudBees, Inc. for SECURITY-2424 - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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