TUCoPS :: Linux :: Red Hat/Fedora :: ciacl096.txt

CIAC L-096 - Red Hat LPRng Vulnerability


                       The U.S. Department of Energy
                     Computer Incident Advisory Center
                           ___  __ __    _     ___
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                             INFORMATION BULLETIN

                          Red Hat LPRng Vulnerability
                    [Red Hat Security Advisory 2001:077-05]

June 14, 2001 20:00 GMT                                           Number L-096
PROBLEM:       At init time LPRng fails to drop supplemental group memberships 
               when it drops uid and gid. 
PLATFORM:      Red Hat Linux 7.0 - alpha and i386 Red Hat Linux 7.1 - i386 
DAMAGE:        When LPRng drops uid and gid it fails to drop any supplemental 
               group memberships. LPRng and its children maintain any 
               supplemental groups that the process starting LPRng had at 
               start time. It is possible to exploit this to gain access to 
               groups that would allow more privileges on the system. 
SOLUTION:      Apply patch as described below. 
VULNERABILITY  The risk is LOW: Although it poses a security risk there are 
ASSESSMENT:    currently no known exploits using this vulnerability. 

[******  Start Red Hat Security Advisory ******]

                   Red Hat, Inc. Red Hat Security Advisory

Synopsis:          LPRng fails to drop supplemental group membership
Advisory ID:       RHSA-2001:077-05
Issue date:        2001-06-07
Updated on:        2001-06-11
Product:           Red Hat Linux
Keywords:          LPRng groups
Cross references:  
Obsoletes:         RHBA-2001:039-05 RHSA-2000:065-06

1. Topic:

When LPRng drops uid and gid, it fails to drop membership in its
supplemental groups.

2. Relevant releases/architectures:

Red Hat Linux 7.0 - alpha, i386

Red Hat Linux 7.1 - i386

3. Problem description:

LPRng fails to drop supplemental group membership at init time, though it
does properly setuid and setgid. The result is that LPRng, and its
children, maintain any supplemental groups that the process starting LPRng
had at the time it started LPRng. This is a security risk.

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:


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

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

43341 - lpd fails to drop groups of root

6. RPMs required:

Red Hat Linux 7.0:




Red Hat Linux 7.1:



7. Verification:

MD5 sum                           Package Name
9a9a148f44c80cb83a1cc53b7fc60492 7.0/en/os/SRPMS/LPRng-3.7.4-23.src.rpm
3a83c1cdf9eef8bbc72bd511264a0fc3 7.0/en/os/alpha/LPRng-3.7.4-23.alpha.rpm
23e85c03c49b6d1eda0a76428f181dc5 7.0/en/os/i386/LPRng-3.7.4-23.i386.rpm
9a9a148f44c80cb83a1cc53b7fc60492 7.1/en/os/SRPMS/LPRng-3.7.4-23.src.rpm
23e85c03c49b6d1eda0a76428f181dc5 7.1/en/os/i386/LPRng-3.7.4-23.i386.rpm

These packages are GPG signed by Red Hat, Inc. for security.  Our key
is available at:

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:

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

[******  End Red Hat Security Advisory ******]

CIAC wishes to acknowledge the contributions of Red Hat Linux for the 
information contained in this bulletin.

CIAC, the Computer Incident Advisory Center, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.

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This document was prepared as an account of work sponsored by an
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