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Red Hat Linux Advisory: PXE

Aug 30, 2002, 21:42 (0 Talkback[s])

                   Red Hat, Inc. Red Hat Security Advisory

Synopsis:          PXE server crashes from certain DHCP packets
Advisory ID:       RHSA-2002:162-12
Issue date:        2002-07-29
Updated on:        2002-08-30
Product:           Red Hat Linux
Keywords:          pxe PXE Voice Over IP (VOIP) phones DHCP packets
Cross references:  RHSA-2002:165
CVE Names:         CAN-2002-0835

1. Topic:

Updated PXE packages are now available for Red Hat Linux which fix a
vulnerability that can crash the PXE server using certain DHCP packets.

2. Relevant releases/architectures:

Red Hat Linux 6.2 - alpha, i386, sparc
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 PXE package contains the PXE (Preboot eXecution Environment)
server and code needed for Linux to boot from a boot disk image on a
Linux PXE server.  

It was found that the PXE server could be crashed using DHCP packets from
some Voice Over IP (VOIP) phones.  This bug could be used to cause a denial
of service attack on remote systems by using malicious packets.

Users of PXE are advised to upgrade to the new release which contains a
version of PXE that is not vulnerable to this issue.

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 ( for more info):

66825 - DHCP packets from Cisco VOIP phone crash pxe server
63945 - PXE does not work on servers

6. RPMs required:

Red Hat Linux 6.2:



Red Hat Linux 7.0:



Red Hat Linux 7.1:



Red Hat Linux 7.2:



Red Hat Linux 7.3:



7. Verification:

MD5 sum                          Package Name
aece8aebd2265dfac76ac528f883e4f2 6.2/en/os/SRPMS/pxe-0.1-
7869c858f80009cf22a1235417cfc3c7 6.2/en/os/i386/pxe-0.1-
fb0aac937bdb8a13cc22a8aa6254cfc7 7.0/en/os/SRPMS/pxe-0.1-
391d65eb419642d2e5d57507b1b8546e 7.0/en/os/i386/pxe-0.1-
fb0aac937bdb8a13cc22a8aa6254cfc7 7.1/en/os/SRPMS/pxe-0.1-
391d65eb419642d2e5d57507b1b8546e 7.1/en/os/i386/pxe-0.1-
fb0aac937bdb8a13cc22a8aa6254cfc7 7.2/en/os/SRPMS/pxe-0.1-
391d65eb419642d2e5d57507b1b8546e 7.2/en/os/i386/pxe-0.1-
fb0aac937bdb8a13cc22a8aa6254cfc7 7.3/en/os/SRPMS/pxe-0.1-
391d65eb419642d2e5d57507b1b8546e 7.3/en/os/i386/pxe-0.1-

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, 2002 Red Hat, Inc.