Rule:  

--
Sid:
1792

--
Summary:
This event is generated when an attempt is made to exploit a known vulnerability in Mnews.

--
Impact:
Serious. Execution of arbitrary code is possible.

--
Detailed Information:
A buffer overflow condition exists in Mnews, an NNTP and mail client.  The overflow can be caused by a server sending enough data with a 200 response to overwrite stack memory and so present the attacker with the oppotunity to execute code of their choosing.

--
Affected Systems:
FreeBSD 4.1
FreeBSD 4.2
FreeBSD 4.3
FreeBSD 4.4
FreeBSD 4.5

--
Attack Scenarios:
The attacker needs to send enough extra data with the 200 response from a server to cause the overflow.

--
Ease of Attack:
Moderate.

--
False Positives:
A message Id of 200 will also set off this rule if the message header is longer than 64 bytes.  This rule is disabled by default

--
False Negatives:
None known

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

--
Contributors:
Sourcefire Research Team
Brian Caswell <bmc@sourcefire.com>
Nigel Houghton <nigel.houghton@sourcefire.com>

-- 
Additional References:

--
