CVE-2021-21300

 

Published at: - 09-03-2021 09:15

Last modified: - 20-10-2022 08:52

Total changes: - 14

Description

Git is an open-source distributed revision control system. In affected versions of Git a specially crafted repository that contains symbolic links as well as files using a clean/smudge filter such as Git LFS, may cause just-checked out script to be executed while cloning onto a case-insensitive file system such as NTFS, HFS+ or APFS (i.e. the default file systems on Windows and macOS). Note that clean/smudge filters have to be configured for that. Git for Windows configures Git LFS by default, and is therefore vulnerable. The problem has been patched in the versions published on Tuesday, March 9th, 2021. As a workaound, if symbolic link support is disabled in Git (e.g. via `git config --global core.symlinks false`), the described attack won't work. Likewise, if no clean/smudge filters such as Git LFS are configured globally (i.e. _before_ cloning), the attack is foiled. As always, it is best to avoid cloning repositories from untrusted sources. The earliest impacted version is 2.14.2. The fix versions are: 2.30.1, 2.29.3, 2.28.1, 2.27.1, 2.26.3, 2.25.5, 2.24.4, 2.23.4, 2.22.5, 2.21.4, 2.20.5, 2.19.6, 2.18.5, 2.17.62.17.6.

Common Vulnerability Scoring System (CVSS)

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

 

Verification logic

 

Reference

• https://github.com/git/git/commit/684dd4c2b414bcf648505e74498a608f28de4592
• https://git-scm.com/docs/gitattributes#_filter
• https://github.com/git/git/security/advisories/GHSA-8prw-h3cq-mghm
• https://lore.kernel.org/git/xmqqim6019yd.fsf@gitster.c.googlers.com/
• https://git-scm.com/docs/git-config#Documentation/git-config.txt-coresymlinks
• [oss-security] 20210309 git: malicious repositories can execute remote code while cloning-Exploit, Mailing List, Third Party Advisory
• FEDORA-2021-63fcbd126e-Third Party Advisory
• FEDORA-2021-ffd0b2108d-Mailing List, Third Party Advisory
• FEDORA-2021-03e61a6647-Mailing List, Third Party Advisory
• https://support.apple.com/kb/HT212320
• 20210427 APPLE-SA-2021-04-26-10 Xcode 12.5-Mailing List, Third Party Advisory
• GLSA-202104-01-Third Party Advisory
• http://packetstormsecurity.com/files/163978/Git-LFS-Clone-Command-Execution.html
• [debian-lts-announce] 20221010 [SECURITY] [DLA 3145-1] git security update-

 

Keywords

NVD

 

CVE-2021-21300

 

CVE

 

Common vulnerabilities & exposures

 

CVSS

 

Common vulnerability scoring system

 

Security

 

Vulnerabilities

 

Exposures