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Red Hat, Inc. Red Hat Security Advisory
Synopsis: Updated mod_ssl packages available
Advisory ID: RHSA-2002:041-08
Issue date: 2002-03-01
Updated on: 2002-03-06
Product: Red Hat Linux
Keywords: mod_ssl buffer overflow session cache
Cross references: RHSA-2002:042
Obsoletes: RHSA-2001:126
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1. Topic:
Updated mod_ssl packages for Red Hat Linux 7, 7.1, and
7.2 are available which close a buffer overflow in mod_ssl.
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
3. Problem description:
When session caching is enabled, mod_ssl will serialize SSL session
variables to store them for later use. Unpatched versions of mod_ssl prior
to version 2.8.7 which use the 'shm' or 'dbm' session caches would store
session variables using a buffer with a fixed size, making it vulnerable to
overflow.
To exploit the overflow, the server must be configured to require client
certificates, and an attacker must obtain a carefully crafted client
certificate that has been signed by a Certificate Authority which is
trusted by the server. If these conditions are met, it would be possible
for an attacker to execute arbitrary code on the server.
Red Hat Linux 6.2 and earlier releases which did not include the mod_ssl
package are not vulnerable to this bug. Users who utilize client
certificate authentication are strongly advised to upgrade or switch to
shared memory session cache, shmcb, which is not vulnerable to this issue.
The Common Vulnerabilities and Exposures project (cve.mitre.org) has
assigned the name CAN-2002-0082 to this issue.
4. Solution:
Before applying this update, make sure to apply all previously released
errata relevant to your system.
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 applying these updates, you will need to restart an active server by
performing the following:
/etc/rc.d/init.d/httpd restart
This step must be performed manually to keep SSL-capable servers from
stalling when the server's key is password-protected.
5. Bug IDs fixed (http://bugzilla.redhat.com/bugzilla for more info):
6. RPMs required:
Red Hat Linux 7.0:
SRPMS:
ftp://updates.redhat.com/7.0/en/os/SRPMS/mod_ssl-2.8.5-3.src.rpm
alpha:
ftp://updates.redhat.com/7.0/en/os/alpha/mod_ssl-2.8.5-3.alpha.rpm
i386:
ftp://updates.redhat.com/7.0/en/os/i386/mod_ssl-2.8.5-3.i386.rpm
Red Hat Linux 7.1:
SRPMS:
ftp://updates.redhat.com/7.1/en/os/SRPMS/mod_ssl-2.8.5-3.src.rpm
alpha:
ftp://updates.redhat.com/7.1/en/os/alpha/mod_ssl-2.8.5-3.alpha.rpm
i386:
ftp://updates.redhat.com/7.1/en/os/i386/mod_ssl-2.8.5-3.i386.rpm
ia64:
ftp://updates.redhat.com/7.1/en/os/ia64/mod_ssl-2.8.5-3.ia64.rpm
Red Hat Linux 7.2:
SRPMS:
ftp://updates.redhat.com/7.2/en/os/SRPMS/mod_ssl-2.8.5-4.src.rpm
i386:
ftp://updates.redhat.com/7.2/en/os/i386/mod_ssl-2.8.5-4.i386.rpm
ia64:
ftp://updates.redhat.com/7.2/en/os/ia64/mod_ssl-2.8.5-4.ia64.rpm
7. Verification:
MD5 sum Package Name
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c48b531b44f2e1b24cd7135a0abeac56 7.0/en/os/SRPMS/mod_ssl-2.8.5-3.src.rpm
cf0f60da9b3552aa3d25a7b758164b24 7.0/en/os/alpha/mod_ssl-2.8.5-3.alpha.rpm
e823561b43670240862e7038293222c7 7.0/en/os/i386/mod_ssl-2.8.5-3.i386.rpm
c48b531b44f2e1b24cd7135a0abeac56 7.1/en/os/SRPMS/mod_ssl-2.8.5-3.src.rpm
cf0f60da9b3552aa3d25a7b758164b24 7.1/en/os/alpha/mod_ssl-2.8.5-3.alpha.rpm
e823561b43670240862e7038293222c7 7.1/en/os/i386/mod_ssl-2.8.5-3.i386.rpm
547de3f8522fb0af6ea2d082de648c7c 7.1/en/os/ia64/mod_ssl-2.8.5-3.ia64.rpm
608249d2e6edecb929e679129e41a1c5 7.2/en/os/SRPMS/mod_ssl-2.8.5-4.src.rpm
b7c91618cfb9110ce1ad620b9df05ab7 7.2/en/os/i386/mod_ssl-2.8.5-4.i386.rpm
1a8fc12f84ed55561a305d47269d312f 7.2/en/os/ia64/mod_ssl-2.8.5-4.ia64.rpm
These packages are GPG signed by Red Hat, Inc. for security. Our key
is available at:
http://www.redhat.com/about/contact/pgpkey.html
You can verify each package with the following command:
rpm --checksig <filename>
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 <filename>
8. References:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-0082
http://marc.theaimsgroup.com/?l=apache-modssl&m=101449247201254
http://online.securityfocus.com/archive/1/258646
Copyright(c) 2000, 2001, 2002 Red Hat, Inc.
