According to: http://www.squid-cache.org/Advisories/SQUID-2007_1.txt "Due to an internal error Squid-2.6 is vulnerable to a denial of service attack when processing the TRACE request method." See http://www.squid-cache.org/Versions/v2/2.6/changesets/11349.patch This may only affect Squid 2.6 and therefore only RHEL5, will need confirmation
I don't believe this is a security flaw. I can send a request to the squid server. The child process does indeed die via an assertion error, but the parent process start a new child to handle the new incoming requests. I've mailed upstream and vendor-sec to see if I'm mistaken. I'll add a note if I'm wrong.
This is going to be considered a security flaw after all. As was pointed out by upstream, since there is only one child process, it would be possible for an attacker to send the same request in a loop which would prevent other users from using the proxy. Since the server can recover, and the attacker must be behind the proxy, we are labeling this as moderate severity.
This issue should be fixed in squid-2.6.STABLE6-4.el5. Package was built and tested. Waiting for advisory.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2007-0131.html