Rule:  

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Sid:
2220

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Summary:
This event is generated when an attempt is made to access simplestmail.cgi on an internal web server. This may indicate an attempt to exploit a remote command execution vulnerability in Leif M. Wright's Simple Guestbook.

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

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Detailed Information:
Leif Wright's Simple Guestbook uses a Perl script to manage web-based guestbook submissions. It improperly parses pipe metacharacters (|), allowing an attacker to place arbitrary shell commands between pipe characters in the guestbook value. These commands are then executed by the web server when it receives the request.

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Affected Systems:
Web servers running Leif M. Wright Simple Guestbook.

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Attack Scenarios:
An attacker uses a specially crafted value in the guestbook field between pipe characters. Any commands included in the value are executed with the security context of the web server.

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Ease of Attack:
Simple. Exploits exist.

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

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False Negatives:
None known.

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Corrective Action:
Disable simplestmail.cgi. 

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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/2106

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