Date: Thu, 3 Sep 1998 18:10:50 -0400
From: CERT Advisory <[email protected]>
To: [email protected]Subject: CERT Advisory CA-98.11 - tooltalk
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CERT* Advisory CA-98.11
Original issue date: September 3, 1998
Topic: Vulnerability in ToolTalk RPC Service
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The text of this advisory was originally released on August 31, 1998, as
NAI-29, developed by Network Associates, Inc. (NAI). To more widely
broadcast this information, we are reprinting the NAI advisory here with
their permission.
As we receive additional information it will be placed in an "Updates"
section at the end of this advisory.
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Stack Overflow in ToolTalk RPC Service
NAI Advisory 29
Network Associates, Inc.
SECURITY ADVISORY
August 31, 1998
SYNOPSIS
An implementation fault in the ToolTalk object database server allows a
remote attacker to run arbitrary code as the superuser on hosts supporting
the ToolTalk service. The affected program runs on many popular UNIX
operating systems supporting CDE and some Open Windows installs. This
vulnerability is being actively exploited by attackers on the Internet.
Confirmed Vulnerable Operating Systems and Third Party Vendors
Sun Microsystems
SunOS 5.6, 5.6_x86
SunOS 5.5.1, 5.5.1_x86
SunOS 5.5, 5.5_x86
SunOS 5.4, 5.4_x86
SunOS 5.3
SunOS 4.1.
SunOS 4.1.3_U1
Hewlett Packard
HP-UX release 10.10
HP-UX release 10.20
HP-UX release 10.30
HP-UX release 11.00
SGI
IRIX 5.3
IRIX 5.4
IRIX 6.2
IRIX 6.3
IRIX 6.4
IBM
AIX 4.1.X
AIX 4.2.X
AIX 4.3.X
TriTeal
TriTeal CDE - TED versions 4.3 and previous.
Xi Graphics
Xi Graphics Maximum CDE v1.2.3
It should be noted here that this not an exhaustive list of vulnerable
vendors. These are only the *confirmed vulnerable* vendors. Also, any OS
installation that is not configured to use or start up the ToolTalk service
is not vulnerable to this problem. To determine whether the ToolTalk
database server is running on a host, use the "rpcinfo" command to print a
list of the RPC services running on it, as:
$ rpcinfo -p hostname
Because many operating systems do not include an entry for the ToolTalk
database service in the RPC mapping table ("/etc/rpc" on most Unix
platforms), the vulnerable service may not appear by name in the listing.
The RPC program number for the ToolTalk database service is 100083. If an
entry exists for this program, such as,
100083 1 tcp 692
then the service is running on the host. Until additional information is
made available from the OS vendor, it should be assumed that the system is
vulnerable to the attack described in this advisory.
DETAILS
The ToolTalk service allows independently developed applications to
communicate with each other by exchanging ToolTalk messages. Using
ToolTalk, applications can create open protocols which allow different
programs to be interchanged, and new programs to be plugged into the system
with minimal reconfiguration.
The ToolTalk database server (rpc.ttdbserverd) is an ONC RPC service which
manages objects needed for the operation of the ToolTalk service.
ToolTalk-enabled processes communicate with each other using RPC calls to
this program, which runs on each ToolTalk-enabled host. This program is a
standard component of the ToolTalk system, which ships as a standard
component of many commercial Unix operating systems. The ToolTalk database
server runs as root.
Due to an implementation fault in rpc.ttdbserverd, it is possible for a
malicious remote client to formulate an RPC message that will cause the
server to overflow an automatic variable on the stack. By overwriting
activation records stored on the stack, it is possible to force a transfer
of control into arbitrary instructions provided by the attacker in the RPC
message, and thus gain total control of the server process.
TECHNICAL DETAILS
Source code and XDR specifications for the ToolTalk database protocol and
server were not available at the time this advisory was drafted. What
follows is information based on analysis of the rpc.ttdbserverd binary and
a captured attack trace from a network on which an exploitation script for
this problem was run.
The observed attack utilized the ToolTalk Database (TTDB) RPC procedure
number 7, with an XDR-encoded string as its sole argument. TTDB procedure 7
corresponds to the _tt_iserase_1() function symbol in the Solaris binary
(/usr/openwin/bin/rpc.ttdbserverd). This function implements an RPC
procedure which takes an ASCII string as an argument, which is treated as a
pathname.
The pathname string is passed to the function isopen(), which in turn
passes it to _am_open(), then to _amopen(), _openfcb(), _isfcb_open(), and
finally to _open_datfile(), where it, as the first argument to the
function, is passed directly to a strcpy() to a pointer on the stack. If
the pathname string is suitably large, the string overflows the stack
buffer and overwrites an activation record, allowing control to transfer
into instructions stored in the pathname string.
RESOLUTION
This is an implementation problem and can only be resolved completely by
applying patches to or replacing affected software. As a temporary
workaround, it is possible to eliminate vulnerability to this problem by
disabling the ToolTalk database service. This can be done by killing the
"rpc.ttdbserverd" process and removing it from any OS startup scripts. It
should be noted that this may impair system functionality.
The following vendors have been confirmed vulnerable, contacted, and have
responded with repair information:
Sun Microsystems
Sun plans to release patches this week that relate to the ToolTalk
vulnerability for SunOS 5.6, 5.6_x86, 5.5.1, 5.5.1_x86, 5.5 and 5.5_x86.
Patches for SunOS 5.4, 5.4_x86, 5.3, 4.1.4 and 4.1.3_U1 will be released in
about 4 weeks.
Sun recommended security patches (including checksums) are
available from: http://sunsolve.sun.com/sunsolve/pubpatches/patches.html
Hewlett Packard
HP-UX has been confirmed vulnerable in releases 10.XX and 11.00. HP has
made patches available with the following identifications:
HP-UX release 10.10 HP9000 Series 7/800 PHSS_16150
HP-UX release 10.20 HP9000 Series 7/800 PHSS_16147
HP-UX release 10.30 HP9000 Series 7/800 PHSS_16151
HP-UX release 11.00 HP9000 Series 7/800 PHSS_16148
IBM
IBM AIX has been confirmed vulnerable. IBM's response is as follows:
The version of ttdbserver shipped with AIX is vulnerable. We are currently
working on the following fixes which will be available soon:
APAR 4.1.x: IX81440
APAR 4.2.x: IX81441
APAR 4.3.x: IX81442
Until the official APARs are available, a temporary fix can be downloaded
via anonymous ftp from:
ftp://aix.software.ibm.com/aix/efixes/security/ttdbserver.tar.Z
TriTeal
An official response from TriTeal is as follows:
The ToolTalk vulnerability will be fixed in the TED4.4 release. For earlier
versions of TED, please contact the TriTeal technical support department at
[email protected] or at http://www.triteal.com/support.
Xi Graphics
An official response from Xi Graphics is as follows:
Xi Graphics Maximum CDE v1.2.3 is vulnerable to this attack. A patch to
correct this problem will be placed on our FTP site by 8/28/1998:
* ftp://ftp.xig.com:/pub/updates/cde/1.2.3/C1203.002.tar.gz
* ftp://ftp.xig.com:/pub/updates/cde/1.2.3/C1203.002.txt
Users of Maximum CDE v1.2.3 are urged to install this update.
Silicon Graphics
The Security Labs team at Network Associates has confirmed that SGI IRIX
6.3 is vulnerable to this attack. SGI's security team has been contacted
and informed of the vulnerability. No repair information has been made
available from Silicon Graphics regarding this problem.
Other Vendors
If any uncertainty exists with regards to whether a given vendor not listed
in this advisory is vulnerable to this attack, we recommend contacting them
via their support/security channels for more information.
ACKNOWLEDGEMENTS
The NAI Security Labs Team would like to thank the HP & IBM Security
Response Teams, CERT/CC & AUSCERT for their contributions to this advisory.
ABOUT THE NETWORK ASSOCIATES SECURITY LABS
The Security Labs at Network Associates hosts some of the most important
research in computer security today. With over 28 published security
advisories published in the last 2 years, the Network Associates security
auditing teams have been responsible for the discovery of many of the
Internet's most serious security flaws. This advisory represents our
ongoing commitment to provide critical information to the security
community.
For more information about the Security Labs at Network Associates, see our
website at http://www.nai.com or contact us at [email protected].
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If you believe that your system has been compromised, contact the CERT
Coordination Center or your representative in the Forum of Incident
Response and Security Teams (see http://www.first.org/team-info/).
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This file: ftp://ftp.cert.org/pub/cert_advisories/CA-98.11.tooltalkhttp://www.cert.org/advisories/CA-98.11.tooltalk.html
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Revision History
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