Snort 2.6.2 Rule Matching Algorithm denial of service

CVSS Meta Temp Score
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CTI Interest Score
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6.5$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Snort 2.6.2. This impacts an unknown function of the component Rule Matching Algorithm. The manipulation leads to denial of service. This vulnerability is referenced as CVE-2006-6931. Furthermore, an exploit is available. It is advised to substitute the affected component with an alternative.

Detailsinfo

A vulnerability was found in Snort 2.6.2. It has been rated as critical. This issue affects an unknown code of the component Rule Matching Algorithm. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

Algorithmic complexity vulnerability in Snort before 2.6.1, during predicate evaluation in rule matching for certain rules, allows remote attackers to cause a denial of service (CPU consumption and detection outage) via crafted network traffic, aka a "backtracking attack."

The bug was discovered 08/16/2006. The weakness was published 01/11/2007 by Studenten Randy Smith, Christian Estan and Somesh with University of Wisconsin-Madison (Website). The advisory is shared at cs.wisc.edu. The identification of this vulnerability is CVE-2006-6931 since 01/16/2007. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are unknown but an exploit is available.

The exploit is available at cs.wisc.edu. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 148 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 24754 (Mandrake Linux Security Advisory : snort (MDKSA-2007:051)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Mandriva Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 34052 (Snort Backtracking Denial of Service Vulnerability).

Applying a patch is able to eliminate this problem. The bugfix is ready for download at snort.org. The problem might be mitigated by replacing the product with as an alternative. The best possible mitigation is suggested to be establishing an alternative product. A possible mitigation has been published 2 months after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (31430), Tenable (24754), SecurityFocus (BID 21991†), OSVDB (32096†) and Secunia (SA24338†). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 6.5

VulDB Base Score: 7.5
VulDB Temp Score: 6.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
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Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

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EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 24754
Nessus Name: Mandrake Linux Security Advisory : snort (MDKSA-2007:051)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
Nessus Port: 🔍

OpenVAS ID: 830299
OpenVAS Name: Zoho ManageEngine Support Center Plus Multiple Fields XSS Vulnerabilities
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Alternative
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Patch: snort.org

Timelineinfo

08/16/2006 🔍
01/10/2007 +147 days 🔍
01/11/2007 +1 days 🔍
01/12/2007 +1 days 🔍
01/12/2007 +0 days 🔍
01/14/2007 +2 days 🔍
01/16/2007 +2 days 🔍
01/16/2007 +0 days 🔍
01/16/2007 +0 days 🔍
02/13/2007 +28 days 🔍
02/24/2007 +11 days 🔍
03/01/2007 +4 days 🔍
03/02/2007 +1 days 🔍
06/14/2025 +6679 days 🔍

Sourcesinfo

Advisory: cs.wisc.edu
Researcher: Studenten Randy Smith, Christian Estan, Somesh
Organization: University of Wisconsin-Madison
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2006-6931 (🔍)
GCVE (CVE): GCVE-0-2006-6931
GCVE (VulDB): GCVE-100-2825
X-Force: 31430 - Snort rule matching denial of service, Medium Risk
SecurityFocus: 21991 - Snort Backtracking Denial of Service Vulnerability
Secunia: 24338 - Mandriva update for snort, Less Critical
OSVDB: 32096 - Snort Rule Predicate Rule Matching Backtrack DoS
SecurityTracker: 1017508
Vulnerability Center: 14015 - Snort Network Intrusion Detection System Remote Denial of Service, Medium

scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 01/16/2007 14:23
Updated: 06/14/2025 21:23
Changes: 01/16/2007 14:23 (99), 07/13/2019 16:39 (1), 06/14/2025 21:23 (20)
Complete: 🔍
Cache ID: 216:1E0:103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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