Luigi Auriemma has discovered a vulnerability in Ipswitch WS_FTP Server, which can be exploited by malicious people to cause a DoS (Denial of Service).

The vulnerability is caused due to the improper handling of UDP packets within the FTP Log Server. This can be exploited to cause the service to stop responding to further log requests by sending multiple overly large datagrams (over 4096 bytes) within a short period of time to port 5151/UDP.

The vulnerability is confirmed in FTP Log Server (ftplogsrv.exe) version 7.9.14.0 included in WS_FTP Server 6.1. Other versions may also be affected.

Solution
Update to WS_FTP Server version 6.1.1.

Provided and/or discovered by
Luigi Auriemma

Changelog
Further details available in Customer Area

Original Advisory
Ipswitch:
http://docs.ipswitch.com/WS_FTP_Server611/ReleaseNotes/index.htm?k_id=ipswitch_ftp_documents_worldwide_ws_ftpserverv611releasenotes#link12

Luigi Auriemma:
http://aluigi.altervista.org/adv/ftplogsrvz-adv.txt

Deep Links
Links available in Customer Area