Rule: -- Sid: 2106 -- Summary: This event is generated when a remote user sends an IMAP LSUB command with invalid data to port 143 on an internal server. This may indicate an attempt to exploit a buffer overflow vulnerability in the IMAP LSUB command. -- Impact: Possible shell access on the IMAP server, leading to arbitrary code execution. The attacker must have a valid IMAP account on the mail server to attempt this exploit. -- Detailed Information: When a large amount of data is sent to a vulnerable IMAP server in the LSUB command, a buffer overflow condition may occur. This can allow the attacker to access the shell, where arbitrary code can be executed. Note that this exploit can only be attempted by a user with a valid IMAP account. -- Affected Systems: Any operating system that runs University of Washington imapd versions 10.234 or 12.264. -- Attack Scenarios: An attacker with an IMAP account on the server can send a sufficiently long LSUB command to the IMAP server, creating a buffer overflow condition. This can then allow the attacker to gain shell access on the compromised server, possibly leading to the execution of arbitrary code. -- Ease of Attack: Simple. Exploits exist, but the user must have a valid IMAP account on the server. -- False Positives: None known. -- False Negatives: None known. -- Corrective Action: Apply the appropriate patches for your operating system. Check the host for signs of compromise. -- Contributors: Sourcefire Research Team Brian Caswell <bmc@sourcefire.com> Sourcefire Technical Publications Team Jen Harvey <jennifer.harvey@sourcefire.com> -- Additional References: Bugtraq http://www.securityfocus.com/bid/1110 CVE http://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE-2000-0284 Nessus http://cgi.nessus.org/plugins/dump.php3?id=10374 --
