(RHSA-2004:133) squid security update

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.