Headline
CVE-2022-24765
Git for Windows is a fork of Git containing Windows-specific patches. This vulnerability affects users working on multi-user machines, where untrusted parties have write access to the same hard disk. Those untrusted parties could create the folder C:\.git, which would be picked up by Git operations run supposedly outside a repository while searching for a Git directory. Git would then respect any config in said Git directory. Git Bash users who set GIT_PS1_SHOWDIRTYSTATE are vulnerable as well. Users who installed posh-gitare vulnerable simply by starting a PowerShell. Users of IDEs such as Visual Studio are vulnerable: simply creating a new project would already read and respect the config specified in C:\.git\config. Users of the Microsoft fork of Git are vulnerable simply by starting a Git Bash. The problem has been patched in Git for Windows v2.35.2. Users unable to upgrade may create the folder .git on all drives where Git commands are run, and remove read/write access from those folders as a workaround. Alternatively, define or extend GIT_CEILING_DIRECTORIES to cover the parent directory of the user profile, e.g. C:\Users if the user profile is located in C:\Users\my-user-name.
Impact
This vulnerability affects users working on multi-user machines, where untrusted parties have write access to the same hard disk. Those untrusted parties could create the folder C:.git, which would be picked up by Git operations run supposedly outside a repository while searching for a Git directory. Git would then respect any config in said Git directory.
Git Bash users who set GIT_PS1_SHOWDIRTYSTATE (as recommended in the Pro Git Book) are vulnerable.
Users who installed posh-git are vulnerable simply by starting a PowerShell.
Users of IDEs such as Visual Studio are vulnerable: simply creating a new project would already read and respect the config specified in C:.git\config.
Users of the Microsoft fork of Git are vulnerable simply by starting a Git Bash.
Patches
The problem has been patched in Git for Windows v2.35.2.
Workarounds
Create the folder .git on all drives where Git commands are run, and remove read/write access from those folders:
mkdir \.git icacls \.git /inheritance:r
Alternatively, define or extend GIT_CEILING_DIRECTORIES to cover the parent directory of the user profile, e.g. C:\Users if the user profile is located in C:\Users\my-user-name.
Credits
Many thanks to 俞晨东 for finding and reporting the vulnerability!
References
- GIT_CEILING_DIRECTORIES
- How to set up a Git-aware Bash prompt, in the Pro Git Book
For more information
CVSS v3.1 Vector AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N/E:P/RL:O/RC:C/CR:X/IR:X/AR:X/MAV:L/MAC:H/MPR:L/MUI:R/MS:U/MC:H/MI:H/MA:N
If you have any questions or comments about this advisory:
- Open an issue in the Git for Windows project
- For sensitive questions or responsible disclosures, email the Git Security mailing list
- Email the Git project or post to Git for Windows’ Google group.
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