Rule:  

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Sid:
2200

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Summary:
This event is generated when an attempt is made to access dnewsweb.cgi on an internal web server. This may indicate an attempt to exploit a buffer overflow vulnerability in NetWin DNews News Server 5.3.

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Impact:
Remote execution of arbitrary code, possibly leading to remote root compromise.

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Detailed Information:
NetWin DNews News is a web-based application that manages remote access to Internet newsgroups. When overly long arguments are used as arguments to some dnewsweb.cgi parameters (including but not limited to "group," "cmd," and "utag"), a buffer overflow condition may occur. This can lead to the remote execution of arbitrary code with the security context of DNews. 

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Affected Systems:
Any operating system running NetWin DNews News Server 5.3 or lower.

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Attack Scenarios:
An attacker transmits an overly long, specially crafted URL to the vulnerable DNews server, causing a buffer overflow condition. The attacker is then able to execute arbitrary code on the server with the security context of DNews. 

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Ease of Attack:
Simple. An exploit exists.

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False Positives:
If a legitimate remote user accesses dnewsweb.cgi, this rule may generate an event.

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False Negatives:
None known.

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Corrective Action:
Upgrade to DNews News Server 5.4 or higher.

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Contributors:
Sourcefire Research Team
Brian Caswell <bmc@sourcefire.com>
Nigel Houghton <nigel.houghton@sourcefire.com>
Sourcefire Technical Publications Team
Jennifer Harvey <jennifer.harvey@sourcefire.com>

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Additional References:
Bugtraq
http://www.securityfocus.com/bid/1172

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