TUCoPS :: Linux :: Red Hat/Fedora :: ciacl084.txt

CIAC L-084 - Red Hat Samba Package tmp Race Condition


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

                   Red Hat Samba Package /tmp Race Condition
                  [Red Hat Security Advisory RHSA-2001:044-08]

May 18, 2001 20:00 GMT                                            Number L-084
PROBLEM:       A race condition in smb client and the smbd printing code could
               allow local users to overwrite any file on the system.
PLATFORM:      Red Hat Linux 5.2 - alpha, i386, sparc Red Hat Linux 6.2 -
               alpha, i386, sparc Red Hat Linux 7.0 - alpha, i386 Red Hat
               Linux 7.1 - i386
DAMAGE:        A malicious local user could create a symbolic link in /tmp and
               overwrite any file on the system.
SOLUTION:      Apply the updated Samba packages described below.
VULNERABILITY  The risk is LOW to MEDIUM, an attacker must already have local
ASSESSMENT:    access to the system.

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

Red Hat, Inc. Red Hat Security Advisory

Synopsis:          New samba packages available to fix /tmp races
Advisory ID:       RHSA-2001:044-08
Issue date:        2001-04-05
Updated on:        2001-05-14
Product:           Red Hat Linux
Keywords:          samba /tmp overwrite
Cross references:  

1. Topic:

New samba packages are available; these packages fix /tmp races
in smbclient and the printing code. By exploiting these vulnerabilities,
local users could overwrite any file in the system.

It is recommended that all samba users upgrade to the fixed packages.
Please note that the packages for Red Hat Linux 6.2 require an updated
logrotate package.

Note: these packages include the security patch from Samba-2.0.9.

2. Relevant releases/architectures:

Red Hat Linux 5.2 - alpha, i386, sparc

Red Hat Linux 6.2 - alpha, i386, sparc

Red Hat Linux 7.0 - alpha, i386

Red Hat Linux 7.1 - i386

3. Problem description:

The printing code in smbd uses predictable filenames in /tmp, and passes
them as an output file to system();  a user could create a symbolic
link in /tmp and then overwrite any file on the system; later on chmod(0666)
is called on the file, leading to even more problems.

The smbclient 'more' and 'mput' commands also used /tmp files insecurely;
this is less of a risk in that these are not normally run as root.

Thanks go to Marcus Meissner (mm@caldera.de) for investigating the issue
and to the Samba team for providing a patch.

4. Solution:

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 directly *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.

Again, note that the packages for Red Hat Linux 6.2 requre an updated
logrotate package.

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

33509 - Samba uses mktemp
33915 - Samba + Quota allows user to pass hard limit; but with gibberish data not 
correct files
31632 - Quota do not work on SAMBA Server.
36424 - security hole allows a user with a shell account to corrupt local devices
28919 - samba logrotate bug fills the partition limit

6. RPMs required:

Red Hat Linux 5.2:





Red Hat Linux 6.2:





Red Hat Linux 7.0:




Red Hat Linux 7.1:



7. Verification:

MD5 sum                           Package Name
c13389ba4bf3318b49e19b6469b2e0fe 5.2/en/os/SRPMS/samba-2.0.5a-2.5.2.src.rpm
3f0a195dbf5a363459926806185e80ba 5.2/en/os/alpha/samba-2.0.5a-2.5.2.alpha.rpm
58aa6febd254fc1e0784fbf6cfcfff02 5.2/en/os/alpha/samba-client-2.0.5a-2.5.2.alpha.rpm
9a12a093f101c98a1532e37299c484ce 5.2/en/os/i386/samba-2.0.5a-2.5.2.i386.rpm
5fda5f6989dea440ccdaf08446412ba9 5.2/en/os/i386/samba-client-2.0.5a-2.5.2.i386.rpm
854c4cb488ab388141b99d477faf3e86 5.2/en/os/sparc/samba-2.0.5a-2.5.2.sparc.rpm
9352f1fda00801b00e63a899770ff8de 5.2/en/os/sparc/samba-client-2.0.5a-2.5.2.sparc.rpm
335f2123c5ce3606db471183dfcdebad 6.2/en/os/SRPMS/logrotate-3.5.2-0.6.src.rpm
e4e697ad704a84c2ea4606be6ed19f5f 6.2/en/os/SRPMS/samba-2.0.8-1.6.src.rpm
f0f9129497c91d12da04cd6219267aa3 6.2/en/os/alpha/logrotate-3.5.2-0.6.alpha.rpm
9622500299782f17bda3657f85a9ad05 6.2/en/os/alpha/samba-2.0.8-1.6.alpha.rpm
c612a2092a1b03295b7d9d9c25af583d 6.2/en/os/alpha/samba-client-2.0.8-1.6.alpha.rpm
7fdd3bdafd9833e33167b33d19d3058f 6.2/en/os/alpha/samba-common-2.0.8-1.6.alpha.rpm
33f4ce1b7967405f33f4ad1cb73fae35 6.2/en/os/i386/logrotate-3.5.2-0.6.i386.rpm
edcecaa0c060f2371225d14ba5f6d908 6.2/en/os/i386/samba-2.0.8-1.6.i386.rpm
21acd09eb2072ec859a622f91d2aaca2 6.2/en/os/i386/samba-client-2.0.8-1.6.i386.rpm
917694eaf3f0d1f640e7ac9ec9acb329 6.2/en/os/i386/samba-common-2.0.8-1.6.i386.rpm
3f14ee70fdb73ba09ef49e4c4f3c6a7f 6.2/en/os/sparc/logrotate-3.5.2-0.6.sparc.rpm
7dd43e058143351a4605df173ede02a3 6.2/en/os/sparc/samba-2.0.8-1.6.sparc.rpm
478fbb5206d9a32208a63202bb5237c5 6.2/en/os/sparc/samba-client-2.0.8-1.6.sparc.rpm
9024c3b3e1a8ce90e9545979b5fd97f2 6.2/en/os/sparc/samba-common-2.0.8-1.6.sparc.rpm
79e6f09ba81d43ee261a278ffd28e60a 7.0/en/os/SRPMS/samba-2.0.8-1.7.src.rpm
cbfae3f2420cfae17b005211a8fdf692 7.0/en/os/alpha/samba-2.0.8-1.7.alpha.rpm
f09d86bd2a942bfea3a89b00960584e3 7.0/en/os/alpha/samba-client-2.0.8-1.7.alpha.rpm
a201143cad04e8cf7c199b247bcab800 7.0/en/os/alpha/samba-common-2.0.8-1.7.alpha.rpm
a8ab5a701ae81d123b45e564e6a780d4 7.0/en/os/i386/samba-2.0.8-1.7.i386.rpm
e7cd3ef7cad58e3be9ae72aa7e7a2b33 7.0/en/os/i386/samba-client-2.0.8-1.7.i386.rpm
2ea653688e214f9b0ca6619967f77076 7.0/en/os/i386/samba-common-2.0.8-1.7.i386.rpm
54613f26efbbfe5c2664bee923e63ce4 7.1/en/os/SRPMS/samba-2.0.8-1.7.1.src.rpm
282c70feb595b651804678407b7d7b08 7.1/en/os/i386/samba-2.0.8-1.7.1.i386.rpm
6e529dfb18f06b18360c755018864f8f 7.1/en/os/i386/samba-client-2.0.8-1.7.1.i386.rpm
e5f9759330d4ac09ea02ddead9c461e1 7.1/en/os/i386/samba-common-2.0.8-1.7.1.i386.rpm
6033af45917b0cbe447187ea56aeaefa 7.1/en/os/i386/samba-swat-2.0.8-1.7.1.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 Advisory ******]


CIAC wishes to acknowledge the contributions of Red Hat 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
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