Hash: SHA1

             AUSCERT External Security Bulletin Redistribution

          Squid Proxy Cache Security Update Advisory SQUID-2010:3
                             7 September 2010


        AusCERT Security Bulletin Summary

Product:           Squid 3.0 through 3.0.STABLE25
                   Squid 3.1 through 3.1.7
                   Squid 3.2 through
Publisher:         Squid
Operating System:  Windows
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------


    Squid Proxy Cache Security Update Advisory SQUID-2010:3

Advisory ID:            SQUID-2010:3
Date:                   September 03, 2010
Summary:                Denial of service in request processing
Affected versions:      Squid 3.0 -> 3.0.STABLE25
                        Squid 3.1 -> 3.1.7
                        Squid 3.2 ->
Fixed in version:       Squid 3.1.8,


Problem Description:

 Due to an internal error in string handling Squid is vulnerable
 to a denial of service attack when processing specially crafted



 This problem allows any trusted client to perform a denial of
 service attack on the Squid service.

 There are applications already in general public use which can
 trigger this problem for 3.1 and 3.2 on occasion without intended


Updated Packages:

 This bug is fixed by Squid versions 3.1.8 and

 In addition, patches addressing this problem for stable releases
 can be found in our patch archives:

Squid 3.0:

Squid 3.1:

 If you are using a prepackaged version of Squid then please refer
 to the package vendor for availability information on updated


Determining if your version is vulnerable:


 All Squid-3.0 versions up to and including 3.0.STABLE25 have
 some risk of being vulnerable to variations of the problem.
 The particular 0-day tests currently known do not trigger it.


 All versions up to and including 3.1.7 are at some risk of being
 vulnerable to the problem and its variations.

 squid.conf containing with "ignore_expect_100 on" are vulnerable
 to the known active 0-day.

 Binaries built with --disable-http-violations are not vulnerable
 to the known active 0-day.


 The beta version is vulnerable under the same conditions
 as for Squid-3.1.



 These workarounds apply only to the known active 0-day triggers.

 1) Checking that ignore_expect_100 squid.conf option is set to
    "off" (the default), or removed completely from squid.conf.


 2) Building Squid with --disable-http-violations.


Contact details for the Squid project:

 For installation / upgrade support on binary packaged versions
 of Squid: Your first point of contact should be your binary
 package vendor.

 If you install and build Squid from the original Squid sources
 then the squid-users@squid-cache.org mailing list is your primary
 support point. For subscription details see

 For reporting of non-security bugs in the latest release
 the squid bugzilla database should be used

 For reporting of security sensitive bugs send an email to the
 squid-bugs@squid-cache.org mailing list. It's a closed list
 (though anyone can post) and security related bug reports are
 treated in confidence until the impact has been established.



 The vulnerability was discovered by Phil Oester.


Revision history:

 2010-08-30 14:19 GMT Initial Report
 2010-09-01 08:04 GMT Patches Released
 2010-09-03 09:00 GMT Initial version

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:


Australian Computer Emergency Response Team
The University of Queensland
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
Comment: http://www.auscert.org.au/render.html?it=1967