rsync before 3.5.0 contains an arbitrary file write vulnerability that allows attackers to write files outside the intended destination tree by specifying an absolute path via –temp-dir or –link-dest options. The rename-confinement logic is bypassed when these options resolve to paths outside the destination tree, enabling attacker-controlled values to write files to arbitrary locations accessible to the rsync process.
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.
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