Some vulnerabilities have been discovered in XM Easy Personal FTP Server, which can be exploited by malicious users to cause a DoS (Denial of Service).

1) An error exists within the processing of directory listing FTP requests. This can be exploited to terminate the FTP service via overly large LIST or NLST requests.

2) A NULL pointer dereference error can be exploited to crash the server by e.g. sending a LIST command without prior use of the PASV or PORT command.

3) An error when attempting to delete a file used by e.g. an append operation can be exploited to render the service unresponsive.

The vulnerabilities are confirmed in version 5.8.0. Other versions may also be affected.

Solution
Restrict access to trusted users only.

Provided and/or discovered by
1) Platen
2, 3) zhangmc[at]mail.ustc.edu.cn

Changelog
Further details available in Customer Area

Original Advisory
1) http://packetstormsecurity.org/0910-exploits/XM-ftp-dos.txt

Deep Links
Links available in Customer Area