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Git LFS can execute a Git binary from the current directory

Critical severity GitHub Reviewed Published Nov 4, 2020 in git-lfs/git-lfs • Updated Feb 1, 2023

Package

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

Affected versions

< 2.12.1

Patched versions

2.12.1

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 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 v2.12.1, which will be released in coordination with this security advisory.

Workarounds

Other than avoiding untrusted repositories, there is no workaround.

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 Nov 4, 2020
Published by the National Vulnerability Database Nov 5, 2020
Reviewed May 21, 2021
Published to the GitHub Advisory Database Feb 11, 2022
Last updated Feb 1, 2023

Severity

Critical

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
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

95.350%
(99th percentile)

Weaknesses

CVE ID

CVE-2020-27955

GHSA ID

GHSA-4g4p-42wc-9f3m

Source code

Credits

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