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Internet Security Systems Security Advisory
October 2, 2001

Multi-Vendor Format String Vulnerability in ToolTalk Service

Synopsis:

ISS X-Force has discovered a format string vulnerability in the ToolTalk
RPC service present on many commercial Unix variants. The ToolTalk
database server (rpc.ttdbserverd) contains a format string vulnerability
that may allow remote attackers to crash the ToolTalk service, or
execute arbitrary code on a target system with super user privilege.

Affected Versions:

HP HP-UX 10.10
HP HP-UX 10.20
HP HP-UX 11.00
HP HP-UX 11.11
IBM AIX 4.3
IBM AIX 5.1
* SGI IRIX 5.2-6.4
Compaq Tru64 DIGITAL UNIX v4.0f
Compaq Tru64 DIGITAL UNIX v4.0g
Compaq Tru64 DIGITAL UNIX v5.0a
Compaq Tru64 DIGITAL UNIX v5.1
Compaq Tru64 DIGITAL UNIX v5.1a
* Sun Solaris 1.1-1.2
* Sun Solaris 2.0-2.7
Sun Solaris 7
Sun Solaris 8

* Note: This list is believed to be accurate, but not all platforms and
versions have been tested. This list may or may not include every
vulnerable platform and version. 

Description:

The ToolTalk architecture is designed to allow custom applications to
communicate with each other over the network. ToolTalk enabled
applications communicate via RPC (Remote Procedure Call) and are
managed by the ToolTalk database server (rpc.ttdbserverd). The
rpc.ttdbserverd is enabled by default on many popular Unix operating
systems, even if its functionality is not needed or if ToolTalk enabled
applications are not present.  

ToolTalk contains a "syslog()" call that will interpret user-supplied
formatting arguments. This call is insecure and allows remote attackers
to control formatting and manipulate data at arbitrary locations in the
memory of the running executable. 

A format string vulnerability is similar to a buffer overflow 
vulnerability in that the result of a successful attack is unauthorized
manipulation of protected memory in a running program. Format string
vulnerabilities manifest when programmers neglect to specify a format
argument when using functions in the "printf" family.  

A secure print function may look like this:
printf(string, "%s");

A vulnerable print function may look like this:
printf(string);

When user-supplied strings encounter a printf function without a
specified format argument, the string is printed without special
formatting. However, if a user creates a string including format
characters and sends it to an insecure printf function, the string can
function as a reference to memory that is normally out of bounds. In
order to prevent this, printf functions must contain a print argument
to securely restrict user-supplied input to specific memory locations.

Recommendations:

ISS X-Force recommends that all affected users apply the appropriate
vendor-supplied patches listed below. X-Force also recommends that if
ToolTalk is not explicitly required, it should be disabled immediately.

ISS X-Force will provide detection and assessment support for this
vulnerability in upcoming X-Press Updates for RealSecure Network
Sensor and Internet Scanner. 

Sun Microsystems, Inc.
Sun has reproduced the vulnerability and is testing a fix. The Sun
patches will be made available at the following location:
http://sunsolve.sun.com/securitypatch 

Hewlett Packard, Inc.
All current HP-UX versions are vulnerable. HP has reproduced the
vulnerability and has made an emergency fix available. HP customers
should refer to HP Security Bulletin #0168 (Document ID HPSBUX0110-168)
for more information. All HP security information is accessible at the
following location:
http://www.itresourcecenter.hp.com/

The HP emergency fix is now available at the following location:
ftp site: hprc.external.hp.com (192.170.19.51).
account: xgraphic
password: xgraphic
directory: ~xgraphic/CDE
file: rpc.ttdbserver.tar.gz

SGI
SGI is currently investigating the vulnerability and will announce a fix
if one is made available. SGI security information is available at the
following location:
http://www.sgi.com/support/security/

Compaq Computer Corporation
Compaq has identified the vulnerability and made patches available.
This patch may be obtained from the following URL address: 
http://www.support.compaq.com/patches/
 
Select BROWSE PATCH TREE and choose the version directory
required.
The patch names are:
  DUV40F17-C0056200-11703-ER-*.tar
  T64V40G17-C0007000-11704-ER-*.tar
  T64V50A17-C0015500-11705-ER-*.tar
  T64V5117-C0065200-11706-ER-*.tar
  T64V51Assb-C0000800-11707-ER-*.tar
Note: The asterisk in the filename indicates the remainder of the
tarfile name may change depending on the applicable date.

This patch can be installed on: 
V4.0f, V4.0g             all patch kits
V5.0a, V5.1, and V5.1a   all patch kits

IBM Corporation
IBM has identified the vulnerability and will provide an emergency fix.
The fix will be made available from the following FTP site:
ftp://aix.software.ibm.com/aix/efixes/security/tooltalk_efix.tar.Z

Additional Information:

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2001-0717 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

Credits:

This vulnerability was discovered and researched by Mark Dowd of the ISS
X-Force. Internet Security Systems would like to thank Sun, HP, Digital,
IBM, SGI and CERT for their response and handling of this vulnerability.

______

About Internet Security Systems (ISS)
Internet Security Systems is a leading global provider of security
management solutions for the Internet, protecting digital assets and
ensuring safe and uninterrupted e-business. With its industry-leading
intrusion detection and vulnerability assessment, remote managed
security services, and strategic consulting and education offerings, ISS
is a trusted security provider to more than 8,000 customers worldwide
including 21 of the 25 largest U.S. commercial banks and the top 10 U.S.
telecommunications companies. Founded in 1994, ISS is headquartered in
Atlanta, GA, with additional offices throughout North America and
international operations in Asia, Australia, Europe, Latin America and
the Middle East. For more information, visit the Internet Security
Systems web site at www.iss.net or call 888-901-7477.

Copyright (c) 2001 Internet Security Systems, Inc.

Permission is hereby granted for the redistribution of this Alert
electronically. It is not to be edited in any way without express
consent of the X-Force. If you wish to reprint the whole or any part
of this Alert in any other medium excluding electronic medium, please
e-mail xforce@iss.net for permission.

Disclaimer

The information within this paper may change without notice. Use of
this information constitutes acceptance for use in an AS IS condition.
There are NO warranties with regard to this information. In no event
shall the author be liable for any damages whatsoever arising out of or
in connection with the use or spread of this information. Any use of
this information is at the user's own risk.

X-Force PGP Key available at: http://xforce.iss.net/sensitive.php
as well as on MIT's PGP key server and PGP.com's key server.

Please send suggestions, updates, and comments to: X-Force
xforce@iss.net of Internet Security Systems, Inc.
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