Froxlor through 2.3.10 is vulnerable to arbitrary file deletion via symlink following in the FTP data deletion cron task. Cron task 8 (deleteFtpData), queued when an FTP account is deleted, calls FileDir::makeCorrectDir() without the $fixed_homedir argument, so the symlink component walk is skipped, and then executes rm -rf as root on the resulting path with string-level guards only. Because makeCorrectDir() appends a trailing slash, GNU rm dereferences a symlink used either as an intermediate path component or as the final component. An authenticated customer who can write to the FTP home directory can plant a symlink between task insertion and cron execution, causing the root cron job to recursively delete arbitrary directory trees, resulting in cross-tenant data destruction and host denial of service. This issue is fixed in Froxlor 2.3.12.
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