GLSA-200403-11 : Squid ACL [url_regex] bypass vulnerability

This script is Copyright (C) 2004-2014 Tenable Network Security, Inc.


Synopsis :

The remote Gentoo host is missing one or more security-related
patches.

Description :

The remote host is affected by the vulnerability described in GLSA-200403-11
(Squid ACL [url_regex] bypass vulnerability)

A bug in Squid allows users to bypass certain access controls by passing a
URL containing '%00' which exploits the Squid decoding function.
This may insert a NUL character into decoded URLs, which may allow users to
bypass url_regex access control lists that are enforced upon them.
In such a scenario, Squid will insert a NUL character after
the'%00' and it will make a comparison between the URL to the end
of the NUL character rather than the contents after it: the comparison does
not result in a match, and the user's request is not denied.

Impact :

Restricted users may be able to bypass url_regex access control lists that
are enforced upon them which may cause unwanted network traffic as well as
a route for other possible exploits. Users of Squid 2.5STABLE4 and below
who require the url_regex features are recommended to upgrade to 2.5STABLE5
to maintain the security of their infrastructure.

Workaround :

A workaround is not currently known for this issue. All users are advised
to upgrade to the latest version of Squid.

See also :

http://www.squid-cache.org/Advisories/SQUID-2004_1.txt
http://www.gentoo.org/security/en/glsa/glsa-200403-11.xml

Solution :

Squid can be updated as follows:
# emerge sync
# emerge -pv '>=net-proxy/squid-2.5.5'
# emerge '>=net-proxy/squid-2.5.5'

Risk factor :

High / CVSS Base Score : 7.5
(CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P)

Family: Gentoo Local Security Checks

Nessus Plugin ID: 14462 (gentoo_GLSA-200403-11.nasl)

Bugtraq ID:

CVE ID: CVE-2004-0189