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

High Nessus Plugin ID 14462


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


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.


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

See Also

Plugin Details

Severity: High

ID: 14462

File Name: gentoo_GLSA-200403-11.nasl

Version: $Revision: 1.12 $

Type: local

Published: 2004/08/30

Modified: 2015/04/13

Dependencies: 12634

Risk Information

Risk Factor: High


Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Vulnerability Information

CPE: p-cpe:/a:gentoo:linux:squid, cpe:/o:gentoo:linux

Required KB Items: Host/local_checks_enabled, Host/Gentoo/release, Host/Gentoo/qpkg-list

Patch Publication Date: 2004/03/30

Reference Information

CVE: CVE-2004-0189

GLSA: 200403-11