We just got this from Parallels:
A flaw in the popular ProFTPD FTP server potentially allows unauthenticated attackers to compromise a server. The problem is caused by a buffer overflow in the pr_netio_telnet_gets() function for evaluating TELNET IAC sequences.
ProFTPD bug report: http://bugs.proftpd.org/show_bug.cgi?id=3521
Parallels Plesk Panel 9.x, 9.5x and 10 include this vulnerability. Parallels will issue Micro Updates (hotfixes) for 9.5.2 and 9.5.3 no later than 12:00 GMT (noon) on Thursday November 11, (7:00am EST in the US) to fix this. The patch for Parallels Plesk Panel 10.01 will be released at 17:00 GMT on Thursday November 11, (12:00pm EST in the US). Patches for Plesk 9.0, 9.22, and 9.3 will be posted by 12 noon GMT on Friday November 12, (7am EST in the US). Parallels updates on this will be coming soon.
Updating to ProFTPD version 1.3.3c or disabling FTP services is the only current solution to this vulnerability.
ProFTPD is capable of processing TELNET IAC sequences on port 21; the sequences enable or disable certain options not supported by the Telnet or FTP protocol itself. The buffer overflow allows attackers to write arbitrary code to the application’s stack and launch it. Updating to version 1.3.3c of ProFTPD solves the problem.
The update also fixes a directory traversal vulnerability which can only be exploited if the “mod_site_misc” module is loaded. This flaw could allow attackers with write privileges to leave their permitted path and delete directories or create symbolic links outside of the path. The module is not loaded or compiled by default.
A Proftpd update for Plesk has been provided by Atomic Rocket Turtle. To apply the update, execute the commands below.
# wget -O - http://www.atomicorp.com/installers/atomic
# yum upgrade psa-proftpd
Please review http://www.parallels.com/products/plesk/ProFTPD
for updates to this security issue.