Rule:

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Sid:
2118

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Summary:
This event is generated when a remote user uses invalid data within an IMAP LIST command sent to port 143 on an internal server. This may indicate an attempt to exploit a buffer overflow vulnerability in the IMAP LIST 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.

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Detailed Information:
When a large amount of data is sent to a vulnerable IMAP server in the LIST 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.

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Affected Systems:
Any operating system that runs University of Washington imapd versions 10.234 or 12.264. 

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Attack Scenarios:
An attacker with an IMAP account on the server can send a sufficiently long LIST 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.

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Ease of Attack:
Simple. Exploits exist, but the user must have a valid IMAP account on the server.

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False Positives:
None known.

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False Negatives:
None known.

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Corrective Action:
Apply the appropriate patches for your operating system.

Check the host for signs of compromise.

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Contributors:
Sourcefire Research Team
Brian Caswell <bmc@sourcefire.com>
Sourcefire Technical Publications Team
Jen Harvey <jennifer.harvey@sourcefire.com>

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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

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