Archive::Tar versions before 3.08 for Perl extract hardlinks to attacker controlled paths outside the extraction directory.
_make_special_file() passes the tar headers linkname to link() without validating it against absolute paths or .. segments, creating a hardlink that shares the victim files inode.
A subsequent write through the extracted name modifies the victim file, and the post-extraction chmod, chown, and utime block in _extract_file() (guarded only against symlinks via -l) applies the tar headers mode, owner, and timestamps to the shared inode during extraction alone.
Weakness
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Archive::tar | Archive::tar_project | * | 3.08 (excluding) |
Potential Mitigations
- Follow the principle of least privilege when assigning access rights to entities in a software system.
- Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/132.html
- https://cwe.mitre.org/data/definitions/17.html
- https://cwe.mitre.org/data/definitions/35.html
- https://cwe.mitre.org/data/definitions/76.html