Rule:  

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Sid:
1600

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Summary:
This event is generated when an attempt is made to read a file on a host using a well known vulnerability in htdig.

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Impact:
Severe. Unauthorized file access

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Detailed Information:
Some versions of htdig allow inclusions to be made from configuration files as a parameter to the htsearch function. Any file can be included by enclosing it in single quotes ('foo').

Using this vulnerability, any single quoted input string (`....`) is included as an index file by htsearch. This allows an attacker to read any file on the host.

This event is generated when a request is made to the cgi script htsearch with file inclusion attempted. Refer to the rule with sid 1601 for further exploitation attempts.

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Affected Systems:
HTDig versions 3.1.1, 3.1.2, 3.1.3, 3.1.4 and 3.2.0b1

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Attack Scenarios:
An attacker can try to include a file in the search parameters for htdig by using the -c flag. For example:
http://www.foo.com/cgi-bin/htsearch?-c%60/anyfile%60

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Ease of Attack:
Simple. No exploit scripts required

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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.

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Contributors:
Sourcefire Research Team
Brian Caswell <bmc@sourcefire.com>
Nigel Houghton <nigel.houghton@sourcefire.com>
Related Snort documentation contributed by Ueli Kistler, <u.kistler@engagesecurity.com>

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Additional References:
Bugtraq:
http://www.securityfocus.com/bid/1026

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