Rule:

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Sid:
2120

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Summary:
This event is generated when a remote user uses the IMAP CREATE command to send a suspiciously long string to port 143 on an internal server. This may indicate an attempt to exploit a buffer overflow vulnerability in the IMAP CREATE command in the Alt-N MDaemon IMAP server. This may also affect other IMAP implementations.

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Impact:
Remote execution of arbitrary code, which could allow an attacker to interfere with or crash mail services. The attacker must have a valid IMAP account and must be authenticated by the mail server to attempt this exploit.

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Detailed Information:
This event may indicate an attempt to exploit a buffer overflow vulnerability in the Alt-N MDaemon IMAP server CREATE command. If an authenticated user creates a folder with a sufficiently long name on the Alt-N MDaemon IMAP server, arbitrary commands can be executed with system privileges. 

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Affected Systems:
Alt-N MDaemon 6.7.5 or Alt-N MDaemon 6.7.9 IMAP servers.

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Attack Scenarios:
An authenticated user can create a new folder with a sufficiently long name, creating a buffer overflow condition. The attacker can then execute arbitrary code with system privileges, which may allow the attacker to interfere with or crash mail services.

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Ease of Attack:
Exploits exist, but the user must have an account and be authenticated before attempting the exploit.

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False Positives:
None known.

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False Negatives:
None known.

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Corrective Action:
Upgrade to the latest non-affected version of the software.

Apply the appropriate vendor supplied patches.

Check the host for signs of compromise.

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

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Additional References:

Nessus
http://cgi.nessus.org/plugins/dump.php3?id=11577

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