Froxlor FTP Cron Symlink Arbitrary File Deletion Vulnerability

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.

• Affected versions: Froxlor through 2.3.10; fixed in 2.3.12.
• Precondition: an authenticated customer who can write to the FTP home directory can plant a symlink between task insertion and cron execution.
• Impact: the root cron job recursively deletes arbitrary directory trees, causing cross-tenant data destruction and host denial of service.