The remote host is vulnerable to a Denial of Service (DoS) attack.
This host is running a vulnerable version of WS_FTP Server. Versions up to and including 5.0.2 are reported prone to a remote denial of service in the processing of the CD command. By providing a malformed path containing '../' characters to the CD command, an attacker may exhaust server resources.
Upgrade to version 5.04 Hotfix 1 or higher.