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Git LFS can execute a Git binary from the current directory on Windows

High severity GitHub Reviewed Published Jan 13, 2021 in git-lfs/git-lfs • Updated Feb 14, 2023

Package

gomod github.com/git-lfs/git-lfs (Go)

Affected versions

< 2.13.2

Patched versions

2.13.2

Description

Impact

On Windows, if Git LFS operates on a malicious repository with a git.bat or git.exe file in the current directory, that program would be executed, permitting the attacker to execute arbitrary code. This does not affect Unix systems.

This is the result of an incomplete fix for CVE-2020-27955.

This issue occurs because on Windows, Go includes (and prefers) the current directory when the name of a command run does not contain a directory separator.

Patches

This version should be patched in v2.13.2, which will be released in coordination with this security advisory.

Workarounds

Other than avoiding untrusted repositories or using a different operating system, there is no workaround.

References

Are there any links users can visit to find out more?

For more information

If you have any questions or comments about this advisory:

  • Start a discussion in the Git LFS discussion page.
  • If you cannot open a discussion, please email the core team using their usernames at github.com.

References

@bk2204 bk2204 published to git-lfs/git-lfs Jan 13, 2021
Reviewed May 21, 2021
Published to the GitHub Advisory Database Feb 15, 2022
Last updated Feb 14, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS score

0.043%
(11th percentile)

Weaknesses

CVE ID

CVE-2021-21237

GHSA ID

GHSA-cx3w-xqmc-84g5

Source code

Credits

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