Rule:

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Sid:
1327

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Summary:
Secure Shell (SSH) is used to remotely manage systems over encrypted TCP
sessions. This event is generated when an attempt is made to exploit 
vulnerable versions of the SSH daemon.

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Impact:
System compromize presenting the attacker with root privileges. Denial 
of Service (DoS) on certain network devices.

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Detailed Information:
A flaw in the CRC32 compensation attack detection code may result in 
arbitrary code execution with the privileges of the user running the SSH
daemon (usually root).

Some Netscreen devices may suffer a Denial of Service.

Affected Systems:
	OpenSSH versions prior to 2.2
	Multiple Cisco network devices
	Multiple Netscreen network devices
	SSH Secure Communications prior to 1.2.31

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Attack Scenarios:
The attacker would need to send specially crafted large SSH packets to 
cause the overflow and present the opportunity to write values to memory
locations.

Exploit scripts are available

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Ease of Attack:
Simple. Exploits are available.

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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.

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Contributors:
Original rule writer unknown
Sourcefire Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

CERT:
http://www.kb.cert.org/vuls/id/945216

Analysis by David Dittrich:
http://staff.washington.edu/dittrich/misc/ssh-analysis.txt

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