A vulnerability in the tail utility of uutils coreutils allows for the exfiltration of sensitive file contents when using the –follow=name option. Unlike GNU tail, the uutils implementation continues to monitor a path after it has been replaced by a symbolic link, subsequently outputting the contents of the links target. In environments where a privileged user (e.g., root) monitors a log directory, a local attacker with write access to that directory can replace a log file with a symlink to a sensitive system file (such as /etc/shadow), causing tail to disclose the contents of the sensitive file.
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 |
|---|---|---|---|
| Coreutils | Uutils | - (including) | - (including) |
| Rust-coreutils | Ubuntu | devel | * |
| Rust-coreutils | Ubuntu | esm-apps/noble | * |
| Rust-coreutils | Ubuntu | noble | * |
| Rust-coreutils | Ubuntu | questing | * |
| Rust-coreutils | Ubuntu | resolute | * |
| Rust-coreutils | Ubuntu | upstream | * |
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