Red Hat: 'squid' ACL bypass vulnerability
Posted by LinuxSecurity.com Team   
RedHat Linux New squid packages are available for Red Hat Linux 7.0 that fix a possible security problem with Squid's HTTP accelerator feature.

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                   Red Hat, Inc. Red Hat Security Advisory

Synopsis:          New squid packages for Red Hat Linux 7.0
Advisory ID:       RHSA-2001:097-04
Issue date:        2001-07-12
Updated on:        2001-07-19
Product:           Red Hat Linux
Keywords:          squid http_accel_host http_accel_with_proxy
Cross references:  
Obsoletes:         
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1. Topic:

New squid packages are available for Red Hat Linux 7.0 that fix a possible
security problem with Squid's HTTP accelerator feature. If Squid was
configured in accelerator-only mode, it was possible for remote users
to portscan machines through the Squid proxy, potentially allowing for
access to machines not otherwise available.

It is recommended that users who use Squid in accelerator-only mode update
to the fixed packages. Note that Red Hat Linux 7.1 is not affected by this
vulnerability, nor are releases prior to Red Hat Linux 7.0.

2. Relevant releases/architectures:

Red Hat Linux 7.0 - alpha, i386

3. Problem description:

If Squid is configured with 'httpd_accel_host ' and
'httpd_accel_with_proxy off', access control lists will not be enabled.
This could allow any remote user to use the squid server to access other
sites, potentially ones that they could not reach otherwise.

Thanks go to Paul Nasrat <pnasrat@uk.now.com> for notifying us of this
vulnerability and to the Squid team for providing the patch.

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:

up2date

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

5. Bug IDs fixed  (http://bugzilla.Red Hat.com/bugzilla for more info):

48026 - Squid passes acl's in httpd_accel mode in squid-2.3.STABLE4

6. RPMs required:

Red Hat Linux 7.0:

SRPMS: 
ftp://updates.Red Hat.com/7.0/en/os/SRPMS/squid-2.3.STABLE4-9.7.src.rpm

alpha: 
ftp://updates.Red Hat.com/7.0/en/os/alpha/squid-2.3.STABLE4-9.7.alpha.rpm

i386: 
ftp://updates.Red Hat.com/7.0/en/os/i386/squid-2.3.STABLE4-9.7.i386.rpm



7. Verification:

MD5 sum                           Package Name
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a72ff722df226623a845d667959b552b 7.0/en/os/SRPMS/squid-2.3.STABLE4-9.7.src.rpm
433b3aba62f07f7d151b95f75339ade7 7.0/en/os/alpha/squid-2.3.STABLE4-9.7.alpha.rpm
adad3217cd16346eb5dcfa13a46d6289 7.0/en/os/i386/squid-2.3.STABLE4-9.7.i386.rpm

These packages are GPG signed by Red Hat, Inc. for security.  Our key
is available at:
     http://www.Red Hat.com/corp/contact.html

You can verify each package with the following command:
    rpm --checksig  

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

8. References:




Copyright(c) 2000, 2001 Red Hat, Inc.