[cobalt-users] ProFTP DoS

["Per Magne Knutsen" <pknutsen@xxxxxxxxx>]

This posting comes from BugTraq. All known versions of ProFTPD are
vulnerable.

WP> Proftpd has memory leakage bug if it executes SIZE FTP command.
WP> Using 5000 SIZE commands causes proftpd to consume over 300kB of
memory.
WP> Exploiting this bug with more SIZE commands gives us simple DoS attack.
WP> Anonymous access is sufficient to use SIZE commands and to exploit this
WP> bug.

Everyday, my log files are crammed with scans for anonymous access. Code
for exploting the above vulnerability is already publically available.

Workarounds:

1) Disable anonymous access (good idea anyway)
2) Disable SIZE command in /etc/proftpd.conf

        <Limit SIZE>
               Deny All
        </Limit>



Med vennlig hilsen / Yours Sincerely,

Per Magne Knutsen
NetHut.no
http://www.nethut.no
mailto: pknutsen@xxxxxxxxxx