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Snort Back Orifice preprocessor buffer overflow

Vulnerability Note VU#175500

Original Release Date: 2005-10-18 | Last Revised: 2005-11-11

Overview

A buffer overflow exists in the Snort Back Orifice preprocessor that may allow a remote, unauthenticated attacker to execute arbitrary code, possibly with elevated privileges.

Description

Snort is an open-source intrusion detection system (IDS). A lack of validation on attacker-controlled data may allow a buffer overflow to occur in the in Snort Back Orifice preprocessor. A remote, unauthenticated attacker may be able to trigger the buffer overflow by sending a specially crafted Back Orifice ping to a vulnerable Snort installation.

To exploit this vulnerability, an attacker does not need to send packets directly to the Snort sensor. It is sufficient to send packets to any of the hosts on the network monitored by Snort.

Impact

A remote attacker can execute arbitrary code with the privileges of the Snort process, typically root or SYSTEM.

Solution


Update

This issue has been addressed in Snort version 2.4.3.


Disable Snort Back Orifice preprocessor

Disabling the Snort Back Orifice preprocessor will mitigate this vulnerability. However, without the Snort preprocessor, the Snort sensor will not detect or prevent Back Orifice traffic. Snort suggests the following steps to disable the Back Orifice preprocessor:

The Back Orifice preprocessor can be disabled by commenting out the line "preprocessor bo" in snort.conf. This can be done in any text editor using the following procedure:

1. Locate the line "preprocessor bo"
2. Comment out this line by preceding it with a hash (#). The new line will look like "#preprocessor bo"
3. Save the file
4. Restart snort

Vendor Information

175500
 

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CVSS Metrics

Group Score Vector
Base 0 AV:--/AC:--/Au:--/C:--/I:--/A:--
Temporal 0 E:Not Defined (ND)/RL:Not Defined (ND)/RC:Not Defined (ND)
Environmental 0 CDP:Not Defined (ND)/TD:Not Defined (ND)/CR:Not Defined (ND)/IR:Not Defined (ND)/AR:Not Defined (ND)

References

Acknowledgements

This vulnerability was researched and reported by Internet Security Systems (ISS).

This document was written by Art Manion and Jeff Gennari.

Other Information

CVE IDs: CVE-2005-3252
Severity Metric: 31.05
Date Public: 2005-10-18
Date First Published: 2005-10-18
Date Last Updated: 2005-11-11 06:14 UTC
Document Revision: 39

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