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Red Hat Linux Adsvisory: squid

Mar 29, 2004, 15:52 (0 Talkback[s])

Red Hat Security Advisory

Synopsis: Updated squid package fixes security vulnerability
Advisory ID: RHSA-2004:134-01
Issue date: 2004-03-29
Updated on: 2004-03-29
Product: Red Hat Linux
Keywords: phishing spoofing
Cross references:
CVE Names: CAN-2004-0189

1. Topic:

An updated squid package is avaliable that fixes a security vulnerability in URL decoding and provides a new ACL type for protecting vulnerable clients.

2. Relevant releases/architectures:

Red Hat Linux 9 - i386

3. Problem description:

Squid is a full-featured Web proxy cache.

A bug was found in the processing of %-encoded characters in a URL in versions of Squid 2.5.STABLE4 and earlier. If a Squid configuration uses Access Control Lists (ACLs), a remote attacker could create URLs that would not be correctly tested against Squid's ACLs, potentially allowing clients to access prohibited URLs.

Users of Squid should update to these erratum packages which are not vulnerable to this issue.

In addition, these packages contain a new Access Control type, "urllogin", which can be used to protect vulnerable Microsoft Internet Explorer clients from accessing URLs that contain login information. Such URLs are often used by fraudsters to trick web users into revealing valuable personal data.

Note that the default Squid configuration does not make use of this new access control type. You must explicitly configure Squid with ACLs that use this new type, in accordance with your own site policies.

4. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied.

To update all RPMs for your particular architecture, run:

rpm -Fvh [filenames]

where [filenames] is a list of the RPMs you wish to upgrade. Only those RPMs which are currently installed will be updated. Those RPMs which are not installed but included in the list will not be updated. Note that you can also use wildcards (*.rpm) if your current directory only contains the desired RPMs.

Please note that this update is also available via Red Hat Network. Many people find this an easier way to apply updates. To use Red Hat Network, launch the Red Hat Update Agent with the following command:


This will start an interactive process that will result in the appropriate RPMs being upgraded on your system.

If up2date fails to connect to Red Hat Network due to SSL Certificate Errors, you need to install a version of the up2date client with an updated certificate. The latest version of up2date is available from the Red Hat FTP site and may also be downloaded directly from the RHN website:


5. RPMs required:

Red Hat Linux 9:



6. Verificationx:

MD5 sum Package Name

3a78ab4b0423bdbfc5b6bb36897b78ce 9/en/os/SRPMS/squid-2.5.STABLE1-3.9.src.rpm
348ca4845204fadad07116be64d9767e 9/en/os/i386/squid-2.5.STABLE1-3.9.i386.rpm

These packages are GPG signed by Red Hat for security. Our key is available from https://www.redhat.com/security/keys.html

You can verify each package with the following command:

rpm --checksig -v <filename>

If you only wish to verify that each package has not been corrupted or tampered with, examine only the md5sum with the following command:

md5sum <filename>

7. References:


8. Contact:

The Red Hat security contact is <secalert@redhat.com>. More contact details at https://www.redhat.com/solutions/security/news/contact.html

Copyright 2003 Red Hat, Inc.