Open-Source CVS Project Plugs Security Leaks

By Ryan Naraine  |  Posted 2005-04-19 Print this article Print

The new versions of the Concurrent Versions System patch multiple serious security vulnerabilities.

Security researchers on Tuesday issued a warning for multiple vulnerabilities in the open-source CVS, a popular program that allows developers to keep track of different development versions of source code.

The most serious of the flaws could allow a remote compromise of unpatched servers, the open-source Concurrent Versions System Project confirmed in an advisory.

The flaws range from buffer overflows and memory leaks that could lead to code execution and denial-of-service attacks.

Security alerts aggregator Secunia has slapped a "moderately critical" rating on the vulnerabilities and recommended that users upgrade to version 1.11.20 immediately.

CVS, also known as the Concurrent Versioning System, implements a version control system that keeps track of all work and changes in the implementation of a software project.

The system is commonly used as a collaboration tool among open-source developers, and the discovery of security flaws could cause serious problems if an attacker embeds malicious code in software revisions and patches.

The CVS Project described the buffer overflow as "potentially serious" but said it may not be exploitable.

It also confirmed that the new version fixes several plugged memory leaks and potentially freed NULL pointers that may have been exploitable for a denial-of-service attack.

The group also warned that several potential vulnerabilities in the contributed Perl scripts have been fixed. "The confirmed vulnerability could allow the execution of arbitrary code on the CVS server, but only if a user already had commit access and if one of the contrib. scripts was installed improperly, a condition which should have been quickly visible to any administrator," the Project said.

A complete description of the problem has been published. Read more here about critical flaws found in CVS last year. "If you were making use of any of the contributed trigger scripts on a CVS server, you should probably still replace them with the new versions, to be on the safe side," the group said.

A fix for this bug, however, is incomplete. "Taint-checking has been enabled in all the contributed Perl scripts intended to be run as trigger scripts, but no attempt has been made to ensure that they still run in taint mode," the advisory read.

The latest security hiccup comes at a crucial time for the CVS Project, which is still reeling from a major server attack last year. On the Project home page, the remnants of that attack are still visible. "The cvshome site is currently being thoroughly cleaned as a direct result of an exploitative code set that attacks a cvs security violation," reads the note that greets visitors.

"The publication of this code makes all sites running cvs with any remote protocol vulnerable. Use the following information to determine if your site is at risk and to access either a patch for this problem or a full source distribution with the fix included," the notice reads.

Check out eWEEK.coms for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at Security Center Editor Larry Seltzers Weblog.


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