Git Local Clone Vulnerability: Exposure of Sensitive Information via Symbolic Links

CVE-2022-39253 · MEDIUM Severity

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

Git is an open source, scalable, distributed revision control system. Versions prior to 2.30.6, 2.31.5, 2.32.4, 2.33.5, 2.34.5, 2.35.5, 2.36.3, and 2.37.4 are subject to exposure of sensitive information to a malicious actor. When performing a local clone (where the source and target of the clone are on the same volume), Git copies the contents of the source's `$GIT_DIR/objects` directory into the destination by either creating hardlinks to the source contents, or copying them (if hardlinks are disabled via `--no-hardlinks`). A malicious actor could convince a victim to clone a repository with a symbolic link pointing at sensitive information on the victim's machine. This can be done either by having the victim clone a malicious repository on the same machine, or having them clone a malicious repository embedded as a bare repository via a submodule from any source, provided they clone with the `--recurse-submodules` option. Git does not create symbolic links in the `$GIT_DIR/objects` directory. The problem has been patched in the versions published on 2022-10-18, and backported to v2.30.x. Potential workarounds: Avoid cloning untrusted repositories using the `--local` optimization when on a shared machine, either by passing the `--no-local` option to `git clone` or cloning from a URL that uses the `file://` scheme. Alternatively, avoid cloning repositories from untrusted sources with `--recurse-submodules` or run `git config --global protocol.file.allow user`.

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