Squid Proxy up to 3.3.7 HTTP Request input validation

CVSS Meta Temp Score
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CTI Interest Score
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A vulnerability was found in Squid Proxy up to 3.3.7 (Firewall Software). It has been declared as critical. Affected by this vulnerability is some unknown processing of the component HTTP Request Handler. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect availability.

The weakness was disclosed 07/13/2013 by Alex Rousskov and Saran Neti with The Measurement Factory/TELUS Security Labs. as not defined advisory (Website). It is possible to read the advisory at squid-cache.org. The public release has been coordinated in cooperation with Squid. This vulnerability is known as CVE-2013-4123 since 06/12/2013. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are unknown but a public exploit is available.

A public exploit has been developed by king cope and been published 2 days after the advisory. It is declared as proof-of-concept. It is possible to download the exploit at seclists.org. The vulnerability scanner Nessus provides a plugin with the ID 68898 (FreeBSD : squid -- denial of service (30a04ab4-ed7b-11e2-8643-8c705af55518)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family FreeBSD Local Security Checks and running in the context local. The commercial vulnerability scanner Qualys is able to test this issue with plugin 166349 (OpenSuSE Security Update for Squid (openSUSE-SU-2013:1435-1)).

Upgrading to version 3.2.13 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability. Furthermore it is possible to detect and prevent this kind of attack with TippingPoint and the filter 13612.

The vulnerability is also documented in the databases at X-Force (85629), Vulnerability Center (SBV-40702) and Tenable (68898).






  • open-source

CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 6.7

VulDB Base Score: 7.5
VulDB Temp Score: 6.7
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Class: Input validation
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: king cope
Download: 🔍

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Nessus ID: 68898
Nessus Name: FreeBSD : squid -- denial of service (30a04ab4-ed7b-11e2-8643-8c705af55518)
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OpenVAS ID: 866539
OpenVAS Name: Fedora Update for squid FEDORA-2013-13468
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Threat Intelligenceinfo

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Recommended: Upgrade
Status: 🔍

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Upgrade: Proxy 3.2.13
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06/12/2013 🔍
07/13/2013 +31 days 🔍
07/13/2013 +0 days 🔍
07/13/2013 +0 days 🔍
07/13/2013 +0 days 🔍
07/15/2013 +2 days 🔍
07/16/2013 +1 days 🔍
07/18/2013 +2 days 🔍
07/25/2013 +7 days 🔍
09/16/2013 +53 days 🔍
11/23/2018 +1894 days 🔍


Vendor: squid-cache.org

Advisory: squid-cache.org
Researcher: Alex Rousskov/Saran Neti
Organization: The Measurement Factory/TELUS Security Labs.
Status: Not defined
Confirmation: 🔍
Coordinated: 🔍

CVE: CVE-2013-4123 (🔍)
X-Force: 85629
Vulnerability Center: 40702 - Squid 3.2 - 3.2.12, 3.3 - 3.3.7 Remote DoS Vulnerability via Crafted HTTP Packet, High
SecurityFocus: 61159 - Squid 'client_side_request.cc' File Remote Denial of Service Vulnerability
Secunia: 54142 - Squid HTTP Header Port Number Handling Denial of Service Vulnerability, Moderately Critical
OSVDB: 95257

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


Created: 07/18/2013 11:58 AM
Updated: 11/23/2018 10:47 AM
Changes: 07/18/2013 11:58 AM (92), 11/23/2018 10:47 AM (5)
Complete: 🔍


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