Check Point Advisories

Squid Authentication Headers Handling Denial of Service (CVE-2005-2917)

Check Point Reference: CPAI-2005-298
Date Published: 3 Nov 2009
Severity: High
Last Updated: Wednesday 03 October, 2018
Industry Reference:CVE-2005-2917
Protection Provided by:

Security Gateway
R81, R80, R77, R75

Who is Vulnerable?
Vulnerability Description The Squid proxy server is an open source, Internet proxy and caching application. It supports the proxying of FTP, HTTP, SSL, and DNS services. The default proxy service port is 3128/TCP. A vulnerability exists in the Squid proxy server in the processing of authentication requests. The flaw is caused by improper handling of malformed NTLM authentication requests. By sending such crafted HTTP requests to the target, a remote malicious user may exploit this vulnerability to terminate an affected Squid proxy server, creating a denial of service condition. Upon receiving a crafted NTLM authentication message, the Squid proxy server will terminate and reset all established connections. However, the Squid monitor process will respawn the worker process automatically which restores the proxy services. If the attack is launched continuously, the target Squid proxy may be put into a lasting denial-of-service condition.

Protection Overview

This protection will detect and block attempts to exploit this vulnerability

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R80 / R77 / R75

  1. In the IPS tab, click Protections and find the Squid Authentication Headers Handling Denial of Service protection using the Search tool and Edit the protection's settings.
  2. Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name:  Proxy Server Enforcement Violation.
Attack Information:  Squid Authentication Headers Handling Denial of Service

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