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             AUSCERT External Security Bulletin Redistribution

                     ESB-2002.484 -- RHSA-2002:162-12
               PXE server crashes from certain DHCP packets
                             02 September 2002

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                PXE server
Vendor:                 Red Hat
Operating System:       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
Platform:               Alpha
                        i386
                        IA-64
                        SPARC
Impact:                 Denial of Service
Access Required:        Remote

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                   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
Obsoletes:         
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:

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.redhat.com/bugzilla 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:

SRPMS:
ftp://updates.redhat.com/6.2/en/os/SRPMS/pxe-0.1-31.100.6.2.src.rpm

i386:
ftp://updates.redhat.com/6.2/en/os/i386/pxe-0.1-31.100.6.2.i386.rpm

Red Hat Linux 7.0:

SRPMS:
ftp://updates.redhat.com/7.0/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm

i386:
ftp://updates.redhat.com/7.0/en/os/i386/pxe-0.1-31.99.7.3.i386.rpm

Red Hat Linux 7.1:

SRPMS:
ftp://updates.redhat.com/7.1/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm

i386:
ftp://updates.redhat.com/7.1/en/os/i386/pxe-0.1-31.99.7.3.i386.rpm

Red Hat Linux 7.2:

SRPMS:
ftp://updates.redhat.com/7.2/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm

i386:
ftp://updates.redhat.com/7.2/en/os/i386/pxe-0.1-31.99.7.3.i386.rpm

Red Hat Linux 7.3:

SRPMS:
ftp://updates.redhat.com/7.3/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm

i386:
ftp://updates.redhat.com/7.3/en/os/i386/pxe-0.1-31.99.7.3.i386.rpm



7. Verification:

MD5 sum                          Package Name
- --------------------------------------------------------------------------
aece8aebd2265dfac76ac528f883e4f2 6.2/en/os/SRPMS/pxe-0.1-31.100.6.2.src.rpm
7869c858f80009cf22a1235417cfc3c7 6.2/en/os/i386/pxe-0.1-31.100.6.2.i386.rpm
fb0aac937bdb8a13cc22a8aa6254cfc7 7.0/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm
391d65eb419642d2e5d57507b1b8546e 7.0/en/os/i386/pxe-0.1-31.99.7.3.i386.rpm
fb0aac937bdb8a13cc22a8aa6254cfc7 7.1/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm
391d65eb419642d2e5d57507b1b8546e 7.1/en/os/i386/pxe-0.1-31.99.7.3.i386.rpm
fb0aac937bdb8a13cc22a8aa6254cfc7 7.2/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm
391d65eb419642d2e5d57507b1b8546e 7.2/en/os/i386/pxe-0.1-31.99.7.3.i386.rpm
fb0aac937bdb8a13cc22a8aa6254cfc7 7.3/en/os/SRPMS/pxe-0.1-31.99.7.3.src.rpm
391d65eb419642d2e5d57507b1b8546e 7.3/en/os/i386/pxe-0.1-31.99.7.3.i386.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-2002-0835


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