Topic

An updated squid package that fixes two security issues and several bugs is
now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having low
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each vulnerability
from the CVE links in the References section.

Description

Squid is a high-performance proxy caching server for web clients,
supporting FTP, Gopher, and HTTP data objects.

A flaw was found in the way Squid processed certain external ACL helper
HTTP header fields that contained a delimiter that was not a comma. A
remote attacker could issue a crafted request to the Squid server, causing
excessive CPU use (up to 100%). (CVE-2009-2855)

Note: The CVE-2009-2855 issue only affected non-default configurations that
use an external ACL helper script.

A flaw was found in the way Squid handled truncated DNS replies. A remote
attacker able to send specially-crafted UDP packets to Squid's DNS client
port could trigger an assertion failure in Squid's child process, causing
that child process to exit. (CVE-2010-0308)

This update also fixes the following bugs:

• Squid's init script returns a non-zero value when trying to stop a

stopped service. This is not LSB compliant and can generate difficulties in
cluster environments. This update makes stopping LSB compliant. (BZ#521926)

• Squid is not currently built to support MAC address filtering in ACLs.

This update includes support for MAC address filtering. (BZ#496170)

• Squid is not currently built to support Kerberos negotiate

authentication. This update enables Kerberos authentication. (BZ#516245)

• Squid does not include the port number as part of URIs it constructs when

configured as an accelerator. This results in a 403 error. This update
corrects this behavior. (BZ#538738)

• the error_map feature does not work if the same handling is set also on

the HTTP server that operates in deflate mode. This update fixes this
issue. (BZ#470843)

All users of squid should upgrade to this updated package, which resolves
these issues. After installing this update, the squid service will be
restarted automatically.

Solution

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

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 496170 - Add arp filter option
• BZ - 516245 - negotiate support not enabled in squid (for kerberized sso)
• BZ - 518182 - CVE-2009-2855 DoS (100% CPU use) while processing certain external ACL helper HTTP headers
• BZ - 521926 - squid 'stop after stop' is not LSB compliant
• BZ - 538738 - Squid accelerator mode works only if port 80 is opened
• BZ - 556389 - CVE-2010-0308 squid: temporary DoS (assertion failure) triggered by truncated DNS packet (SQUID-2010:1)

CVEs

• CVE-2009-2855
• CVE-2010-0308

References

• http://www.redhat.com/security/updates/classification/#low