Rule:

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Sid:
2012

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Summary:
CVS is the Concurrent Versions System, commonly used to 
help manage software development.

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Impact:
This may be an intelligence gathering activity or an attempt to connect 
to CVS using the credentials of a user with escalated privileges. Should
this attempt be succesful the entire CVS repository may be compromised.

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Detailed Information:
This rule detects attempts to connect to a CVS repository that fail due 
determined activity by an attacker to gain unauthorized access to the 
CVS respository.

The source code of software in the repository may be compromised by a 
succesful attacker who could choose to insert malicious code of his own 
making.

For CVS daemons running under changed root conditions (chroot), the rest
of the operating system files may be protected but the entire CVS 
directory structure and contents is vulnerable.

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Affected Systems:
	All versions of CVS
	
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Attack Scenarios:
This may be an intelligence gathering activity or an attempt to log in 
to CVS using the credentials of an authorized user.

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Ease of Attack:
Simple.

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False Positives:
It is possible that the cvsroot on the server is misconfigured. Check 
permissions on the cvsroot to ensure the repository is writable by the 
cvsdaemon.

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False Negatives:
Connections to the server using zlib compression will not generate this
event.

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Corrective Action:
Disable the CVS daemon in the file /etc/inetd.conf. Run the CVS daemon 
as a user other than root that does not have a valid login to the 
machine.

Disable anonymous cvs access to the server where appropriate.

Maintain checks on the password database and the CVS repository.

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

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Additional References:

CVS:
http://www.cvshome.org/docs/

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