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AUSCERT External Security Bulletin Redistribution
ESB-2002.443 -- IBM SECURITY ADVISORY
Vulnerabilities in CDE ToolTalk RPC Database Server
16 August 2002
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AusCERT Security Bulletin Summary
---------------------------------
Product: CDE ToolTalk RPC Database Server
Operating System: AIX 4.3
AIX 5.1
Impact: Root Compromise
Execute Arbitrary Code/Commands
Denial of Service
Access Required: Remote
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IBM SECURITY ADVISORY
Initial Release: Mon Aug 12 16:35:38 CDT 2002
===========================================================================
VULNERABILITY SUMMARY
VULNERABILITY: Vulnerabilities in CDE ToolTalk RPC Database Server
PLATFORMS: IBM AIX 4.3 and 5.1
SOLUTION: Apply the emergency-fixes described below
THREAT: Malicious remote user can cause denial of service,
possibly execute arbitrary code.
CERT Advisory: CA-2002-26
CERT VU Number: VU#387387
CVE Number: CAN-2002-0679
===========================================================================
DETAILED INFORMATION
I. Description
This advisory addresses a vulnerability in the CDE ToolTalk RPC database
server. This vulnerability is summarized below. Further details can be
found in the CERT advisory and vulnerability notes.
The ToolTalk RPC database server is a component of the CDE desktop and
allows applications to communicate with each other via RPC calls between
different machines and platforms. The RPC database server manages connections
between these ToolTalk applications. This component is vulnerable to a
buffer overflow condition via the _TT_CREATE_FILE() function. By using a
specially crafted RPC message, an attacker could cause a denial of service
condition or possibly execute arbitrary code.
II. Impact
A malicious remote user can use this vulnerability in combination with
other techniques to execute arbitrary code. Since the server usually runs as
root, this can enable a remote attacker to gain root privileges and/or
cause a denial of service condition on the machine.
III. Solutions
A. Official fix
AIX 4.3: APAR #IY32792
AIX 5.1: APAR #IY32793
NOTE: Fix will not be provided for versions prior to 4.3 as
these are no longer supported by IBM. Affected customers are
urged to upgrade to 4.3.3 at the latest maintenance level,
or to 5.1.
B. How to minimize the vulnerability
WORKAROUND
The only workaround currently it to disable the CDE Tooltalk RPC database server
and kill any running rpc.ttdbserver processes.
This can be accomplished on AIX by first commenting-out the rpc.ttdbserver entry in
the /etc/inetd.conf file using the "#" character.
#ttdbserver sunrpc_tcp tcp wait root /usr/dt/bin/rpc.ttdbserver
Then send the inetd process a HUP signal to re-read inetd.conf using the following
commands:
# ps -ef | grep -v grep | grep inetd # to get inetd-pid
# kill -HUP inetd-pid # send HUP signal to inetd
Any currently running rpc.ttdbserver processes must also be killed. This
can be done as follows:
# ps -ef | grep -v grep | grep ttdbserver # to get ttdbserver pid
# kill -HUP ttdbserver-pid # kill ttdbserver process
Note: If you choose to disable ttdbserver, be sure re-enable it after installing
the efix or APAR.
EMERGENCY FIX (efix):
Download the efix:
------------------
Temporary fixes for AIX 4.3.3 and 5.1 systems are available.
The temporary fixes can be downloaded via ftp from:
ftp://aix.software.ibm.com/aix/efixes/security
The name of the efix you want to download to close this vulnerability is
ttdbserver_3_efix.tar.Z.
Unpack and Verify the efix:
---------------------------
Move the efix package to a temporary directory and unpack it using the
following commands:
# uncompress ttdbserver_3_efix.tar.Z
# tar -xvf ttdbserver_3_efix.tar
This package contains a PGP-signed advisory and tarfiles of the patched
rpc.ttdbserver binaries for AIX 4.3.3 and AIX 5.1.0. Detached PGP signatures
are also provided for the tarfiles. The checksums for the tarfiles were
generated using the "sum" and "md5" commands and are as follows:
Filename sum md5
==========================================================================
rpc.ttdbserver.433.tar 56609 350 101a82994e0ac438e4a7d6156d7ce47c
rpc.ttdbserver.510.tar 33997 340 8bb06eaab06646e2c589d57f5e7241ce
These sums should match exactly; if they do not, double check the hash
results and the download site address. If OK, contact IBM AIX Security
at security-alert@austin.ibm.com and describe the discrepancy.
efix Installation Instructions:
-------------------------------
1. Become root, if not already done.
2. Untar the tar file for your AIX release into a temporary directory.
This will create a directory tree under the temporary directory
containing the executable. In this case, "usr/dt/bin".
3. To replace rpc.ttdbserver use the following commands:
# cd /usr/dt/bin
# mv rpc.ttdbserver rpc.ttdbserver.orig # make a backup copy!
# mv /tmp/usr/dt/bin/rpc.ttdbserver.xx . # "xx" = 433 or 510
# mv rpc.ttdbserver.xx rpc.ttdbserver # "xx" = 433 or 510
# chmod 555 rpc.ttdbserver
# chown bin:bin rpc.ttdbserver
# slibclean
Finally, exit the CDE and re-login.
IV. Obtaining Fixes
IBM AIX APARs may be ordered using Electronic Fix Distribution (via the
FixDist program), or from the IBM Support Center. For more information
on FixDist, and to obtain fixes via the Internet, please reference
http://techsupport.services.ibm.com/rs6k/fixes.html
or send email to "aixserv@austin.ibm.com" with the word "FixDist" in the
"Subject:" line.
To facilitate ease of ordering all security related APARs for each AIX
release, security fixes are periodically bundled into a cumulative APAR.
For more information on these cumulative APARs including last update and
list of individual fixes, send email to "aixserv@austin.ibm.com" with
the word "subscribe Security_APARs" in the "Subject:" line.
V. Acknowledgments
Thanks to Sinan Eren of Entercept Technologies for identifying this
vulnerability in CDE ToolTalk and to CERT for notifying us regarding
these security issues.
VI. Contact Information
Comments regarding the content of this announcement can be directed to:
security-alert@austin.ibm.com
To request the PGP public key that can be used to encrypt new AIX
security vulnerabilities, send email to security-alert@austin.ibm.com
with a subject of "get key".
If you would like to subscribe to the AIX security newsletter, send a
note to aixserv@austin.ibm.com with a subject of "subscribe Security".
To cancel your subscription, use a subject of "unsubscribe Security".
To see a list of other available subscriptions, use a subject of
"help".
IBM and AIX are a registered trademark of International Business
Machines Corporation. All other trademarks are property of their
respective holders.
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