Vulnerability in Snort DCE/RPC preprocessor

Sourcefire has learned of a remotely exploitable vulnerability in the Snort DCE/RPC preprocessor. This preprocessor is vulnerable to a stack-based buffer overflow that could potentially allow attackers to execute code with the same privileges as the Snort binary. Sourcefire has prepared updates for Snort open-source software to address this issue.

This vulnerability has been identified as CVE-2006-5276.

Snort Versions Affected:

* Snort 2.6.1, 2.6.1.1, and 2.6.1.2
* Snort 2.7.0 beta 1

This vulnerability also affects Sourcefire commercial products. For information and updates for Sourcefire products, please go to the Sourcefire support site.

Mitigating Factors:

Users who have disabled the DCE/RPC preprocessor are not vulnerable.
However, the DCE/RPC preprocessor is enabled by default.

Recommended Actions:

* Open-source Snort 2.6.1.x users are advised to upgrade to Snort 2.6.1.3 (or later) immediately.
* Open-source Snort 2.7 beta users are advised to mitigate this issue by disabling the DCE/RPC preprocessor.

This issue will be resolved in Snort 2.7 beta 2.

Workarounds:

Snort users who cannot upgrade immediately are advised to disable the DCE/RPC preprocessor by removing the DCE/RPC preprocessor directives from snort.conf and restarting Snort. However, be advised that disabling the DCE/RPC preprocessor reduces detection capabilities for attacks in DCE/RPC traffic. After upgrading, customers should reenable the DCE/RPC preprocessor.

Detecting Attacks Against This Vulnerability:

Sourcefire will be releasing a rule pack that provides detection for attacks against this vulnerability.

FAQs:

What does the update do?
– Snort 2.6.1.3 (or later) removes the vulnerability by correcting the buffer overflow condition in the DCE/RPC preprocessor.

Has Sourcefire received any reports that this vulnerability has been exploited?
– No. Sourcefire has not received any reports that this vulnerability has been exploited.

Acknowledgments:

Sourcefire would like to thank Neel Mehta from IBM X-Force for reporting this issue and working with us to resolve it.




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