Rule:

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Sid:
2013

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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 view a 
module the user does not have access to. 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 
indicate 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.

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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 view a
module the user may not have access to.

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Ease of Attack:
Simple.

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False Positives:
It is possible that an authorized user may mis-type the module name.

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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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