RedHat: 'mod_ssl' Buffer overflow vulnerability
Posted by LinuxSecurity.com Team   
RedHat Linux Updated mod_ssl packages are now available for Red Hat Linux 7, 7.1, 7.2,and 7.3. These updates incorporate a fix for an incorrect bounds check inversions of mod_ssl up to and including version 2.8.9.

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                   Red Hat, Inc. Red Hat Security Advisory

Synopsis:          Updated mod_ssl packages available
Advisory ID:       RHSA-2002:134-12
Issue date:        2002-07-01
Updated on:        2002-07-16
Product:           Red Hat Linux
Keywords:          mod_ssl overflow
Cross references:  RHSA-2002:135 RHSA-2002:136
Obsoletes:         RHSA-2002:041
CVE Names:         CAN-2002-0653
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1. Topic:

Updated mod_ssl packages are now available for Red Hat Linux 7, 7.1, 7.2,
and 7.3. These updates incorporate a fix for an incorrect bounds check in
versions of mod_ssl up to and including version 2.8.9.

2. Relevant releases/architectures:

Red Hat Linux 7.0 - alpha, i386

Red Hat Linux 7.1 - alpha, i386, ia64

Red Hat Linux 7.2 - i386, ia64

Red Hat Linux 7.3 - i386

3. Problem description:

The mod_ssl module provides strong cryptography for the Apache Web
server via the Secure Sockets Layer (SSL) and Transport Layer Security
(TLS) protocols.  Versions of mod_ssl prior to 2.8.10 are subject to a
single NULL overflow that can cause arbitrary code execution.

In order to exploit this vulnerability, the Apache Web server has to be
configured to allow overriding of configuration settings on a per-directory
basis, and untrusted local users must be able to modify a directory in
which the server is configured to allow overriding.  The local attacker may
then become the user that Apache is running as (usually 'www' or 'nobody').  

Note that regardless of this bug, local users can obtain the same
privileges if the server is configured to allow them to create CGI scripts
which run as the Web server user, or if PHP is enabled but not configured
in "safe mode".

The errata packages contain versions of mod_ssl that have been patched and
are not vulnerable to this issue.

Please note that you must restart the httpd daemon to use the updated
module. For instructions on doing this, see the bottom of the Solutions
section below.

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.

After the appropriate updates have been applied, it will be necessary to
manually restart the server with the following command:

/sbin/service httpd restart

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



6. RPMs required:

Red Hat Linux 7.0:

SRPMS: 
ftp://updates.Red Hat.com/7.0/en/os/SRPMS/mod_ssl-2.8.5-5.src.rpm

alpha: 
ftp://updates.Red Hat.com/7.0/en/os/alpha/mod_ssl-2.8.5-5.alpha.rpm

i386: 
ftp://updates.Red Hat.com/7.0/en/os/i386/mod_ssl-2.8.5-5.i386.rpm

Red Hat Linux 7.1:

SRPMS: 
ftp://updates.Red Hat.com/7.1/en/os/SRPMS/mod_ssl-2.8.5-5.src.rpm

alpha: 
ftp://updates.Red Hat.com/7.1/en/os/alpha/mod_ssl-2.8.5-5.alpha.rpm

i386: 
ftp://updates.Red Hat.com/7.1/en/os/i386/mod_ssl-2.8.5-5.i386.rpm

ia64: 
ftp://updates.Red Hat.com/7.1/en/os/ia64/mod_ssl-2.8.5-5.ia64.rpm

Red Hat Linux 7.2:

SRPMS: 
ftp://updates.Red Hat.com/7.2/en/os/SRPMS/mod_ssl-2.8.5-6.src.rpm

i386: 
ftp://updates.Red Hat.com/7.2/en/os/i386/mod_ssl-2.8.5-6.i386.rpm

ia64: 
ftp://updates.Red Hat.com/7.2/en/os/ia64/mod_ssl-2.8.5-6.ia64.rpm

Red Hat Linux 7.3:

SRPMS: 
ftp://updates.Red Hat.com/7.3/en/os/SRPMS/mod_ssl-2.8.7-6.src.rpm

i386: 
ftp://updates.Red Hat.com/7.3/en/os/i386/mod_ssl-2.8.7-6.i386.rpm



7. Verification:

MD5 sum                          Package Name
--------------------------------------------------------------------------
68f324107e24931fbd3c13fd7f0a4f66 7.0/en/os/SRPMS/mod_ssl-2.8.5-5.src.rpm
5505cb06688d8d669a927dc5a29d0bac 7.0/en/os/alpha/mod_ssl-2.8.5-5.alpha.rpm
2fdd482796a973447d19e01cf8a11603 7.0/en/os/i386/mod_ssl-2.8.5-5.i386.rpm
68f324107e24931fbd3c13fd7f0a4f66 7.1/en/os/SRPMS/mod_ssl-2.8.5-5.src.rpm
5505cb06688d8d669a927dc5a29d0bac 7.1/en/os/alpha/mod_ssl-2.8.5-5.alpha.rpm
2fdd482796a973447d19e01cf8a11603 7.1/en/os/i386/mod_ssl-2.8.5-5.i386.rpm
9a0d26822a4055ccf1433d92c0c565a2 7.1/en/os/ia64/mod_ssl-2.8.5-5.ia64.rpm
39e695b50d1a2496cad55cf396ea5d88 7.2/en/os/SRPMS/mod_ssl-2.8.5-6.src.rpm
4a18209d091f3c8bbc2edc21ddbc0ae8 7.2/en/os/i386/mod_ssl-2.8.5-6.i386.rpm
56781cdd2dc2ca137aabe23d587ce783 7.2/en/os/ia64/mod_ssl-2.8.5-6.ia64.rpm
f7388246313fc23b83228361671fa8ff 7.3/en/os/SRPMS/mod_ssl-2.8.7-6.src.rpm
8c9e4f55866bd16df07bc945766bc680 7.3/en/os/i386/mod_ssl-2.8.7-6.i386.rpm
 

These packages are GPG signed by Red Hat, Inc. for security.  Our key
is available at:
     http://www.Red Hat.com/about/contact/pgpkey.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:
 
http://marc.theaimsgroup.com/?l=apache-modssl&m=102491918531562 
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-0653



Copyright(c) 2000, 2001, 2002 Red Hat, Inc.