Rule:--Sid:2106--Summary:This event is generated when a remote user sends an IMAP LSUB commandwith invalid data to port 143 on an internal server. This may indicatean attempt to exploit a buffer overflow vulnerability in the IMAP LSUBcommand. This vulnerability may affect other IMAP implementations.--Impact:Possible shell access on the IMAP server, leading to arbitrary codeexecution. The attacker must have a valid IMAP account on the mailserver to attempt this exploit.--Detailed Information:When a large amount of data is sent to a vulnerable IMAP server in theLSUB command, a buffer overflow condition may occur. This can allow theattacker to access the shell, where arbitrary code can be executed. Notethat this exploit can only be attempted by a user with a valid IMAP account.--Affected Systems:	University of Washington imapd versions 10.234 or 12.264. --Attack Scenarios:An attacker with an IMAP account on the server can send a sufficientlylong LSUB command to the IMAP server, creating a buffer overflowcondition. This can then allow the attacker to gain shell access on thecompromised server, possibly leading to the execution of arbitrary code.--Ease of Attack:Simple. Exploits exist, but the user must have a valid IMAP account onthe server.--False Positives:None known.--False Negatives:None known.--Corrective Action:Upgrade to the latest non-affected version of the software.Apply the appropriate patches for your operating system.Check the host for signs of compromise.--Contributors:Sourcefire Vulneratility Research TeamBrian Caswell <bmc@sourcefire.com>Sourcefire Technical Publications TeamJen Harvey <jennifer.harvey@sourcefire.com>--Additional References:Bugtraqhttp://www.securityfocus.com/bid/1110CVEhttp://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2000-0284 Nessushttp://cgi.nessus.org/plugins/dump.php3?id=10374--