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11 August 2003

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             AUSCERT External Security Bulletin Redistribution

                     ESB-2003.0556 -- RHSA-2003:255-01
            up2date improperly checks GPG signature of packages
                              11 August 2003


        AusCERT Security Bulletin Summary

Product:                up2date
Publisher:              Red Hat
Operating System:       Red Hat Linux 9
                        Red Hat Linux 8.0
Impact:                 Reduced Security
Access Required:        Remote
CVE Names:              CAN-2003-0546

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Hash: SHA1

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                   Red Hat Security Advisory

Synopsis:          up2date improperly checks GPG signature of packages
Advisory ID:       RHSA-2003:255-01
Issue date:        2003-08-08
Updated on:        2003-08-08
Product:           Red Hat Linux
Keywords:          up2date gpg Red Hat Network RHN rpm
Cross references:  
CVE Names:         CAN-2003-0546
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1. Topic:

Updated up2date packages for Red Hat Linux 8.0 and 9 fix RPM GPG signature

2. Relevant releases/architectures:

Red Hat Linux 8.0 - i386
Red Hat Linux 9 - i386

3. Problem description:

The Red Hat Update Agent, up2date, automatically queries the Red Hat
Network servers and determines which packages need to be updated on
your machine.

up2date versions 3.0.7 and 3.1.23 incorrectly check RPM GPG signatures.
These are the versions found in Red Hat Linux 8.0 and 9.

This bug allows packages which have no GPG signature to be installed by
up2date if they are provided by the Red Hat Network servers.  The intended
behaviour is that only packages signed with the Red Hat package signing key
will be installed. 

For an attacker to make use of this flaw, they would have to make unsigned
packages appear on the Red Hat Network. Connections to the Red Hat Network
servers are authenticated and verified by the use of SSL, so it is not
possible to intercept the connection to Red Hat Network servers and give
unsigned packages.  To make use of this flaw, an attacker would
have to compromise the Red Hat Network servers at Red Hat.

Because of these factors, the risk of exploiting this bug is low.  However,
we advise that all users of up2date update to these erratum packages.

Note that all other variations of package signature checks work

The fix was to change the code so that packages with no GPG signature
are rejected in the same way as those with bad GPG signatures (the
up2date client refuses to install them).

Red Hat would like to thank Barry Nathan for finding and reporting this error.

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. RPMs required:

Red Hat Linux 8.0:



Red Hat Linux 9:



6. Verification:

MD5 sum                          Package Name
- - --------------------------------------------------------------------------
606193c00a7fb419b4952b68f1245082 8.0/en/os/SRPMS/up2date-
be91944cf454244846a96b94a3efaa74 8.0/en/os/i386/up2date-
0adeb9cf7fff1754d183894fa40111bc 8.0/en/os/i386/up2date-gnome-
99d3b05223b596cf8d949c27b48e2ebd 9/en/os/SRPMS/up2date-
c6e89c3f118b5734a34d7275d8156596 9/en/os/i386/up2date-
bf0b79cfeaaa6ed947609a27da5c2d65 9/en/os/i386/up2date-gnome-

These packages are GPG signed by Red Hat for security.  Our key is
available from http://www.redhat.com/security/keys.html

You can verify each package with the following command:
    rpm --checksig -v <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:
    md5sum <filename>

7. References:


8. Contact:

The Red Hat security contact is <secalert@redhat.com>.  More contact
details at http://www.redhat.com/solutions/security/news/contact.html

Copyright 2003 Red Hat, Inc.
Version: GnuPG v1.0.7 (GNU/Linux)


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