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CERT* Advisory CA-97.26
Original issue date: Dec. 5, 1997
Last revised:
Topic: Buffer Overrun Vulnerability in statd(1M) Program
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The text of this advisory was originally released on December 5, 1997, as
AA-97.29, developed by the Australian Computer Emergency Response Team. To
more widely broadcast this information, we are reprinting the AUSCERT
advisory here with their permission. Only the contact information at the
end has changed: AUSCERT contact information has been replaced with CERT/CC
contact information.
We will update this advisory as we receive additional information.
Look for it in an "Updates" section at the end of the advisory.
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AUSCERT has received information that a vulnerability exists in the
statd(1M) program, available on a variety of Unix platforms.
This vulnerability may allow local users, as well as remote users to gain
root privileges.
Exploit information involving this vulnerability has been made publicly
available.
This vulnerability is different to the statd vulnerability described
in CERT/CC advisory CA-96.09.
The vulnerability in statd affects various vendor versions of statd.
AUSCERT recommends that sites take the steps outlined in section 3 as soon
as possible.
This advisory will be updated as more information becomes available.
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1. Description
AUSCERT has received information concerning a vulnerability in some
vendor versions of the RPC server, statd(1M).
statd provides network status monitoring. It interacts with lockd to
provide crash and recovery functions for the locking services on NFS.
Due to insufficient bounds checking on input arguments which may be
supplied by local users, as well as remote users, it is possible to
overwrite the internal stack space of the statd program while it is
executing a specific rpc routine. By supplying a carefully designed
input argument to the statd program, intruders may be able to force
statd to execute arbitrary commands as the user running statd. In most
instances, this will be root.
This vulnerability may be exploited by local users. It can also be
exploited remotely without the intruder requiring a valid local account
if statd is accessible via the network.
Sites can check whether they are running statd by:
On system V like systems:
# ps -fe |grep statd
root 973 1 0 14:41:46 ? 0:00 /usr/lib/nfs/statd
On BSD like systems:
# ps -auxw |grep statd
root 156 0.0 0.0 52 0 ? IW May 3 0:00 rpc.statd
Specific vendor information regarding this vulnerability can be found
in Section 3.
2. Impact
This vulnerability permits attackers to gain root privileges. It can
be exploited by local users. It can also be exploited remotely without
the intruder requiring a valid local account if statd is accessible
via the network.
3. Workarounds/Solution
The statd program is available on many different systems. As vendor
patches are made available sites are encouraged to install them
immediately (Section 3.1).
If you are not using NFS in your environment then there is no need
for the statd program to be running and it can be disabled (Section
3.2).
3.1 Vendor information
The following vendors have provided information concerning the
vulnerability in statd.
BSDI
Digital Equipment Corporation
Hewlett Packard
IBM Corporation
The NetBSD Project
Red Hat Software
Sun Microsystems
Specific vendor information has been placed in Appendix A.
If the statd program is required at your site and your vendor is not
listed, you should contact your vendor directly.
If you do not require the statd program then it should be disabled
(Section 3.2).
3.2 Disabling statd
The statd daemon is required as part of an NFS environment. If you
are not using NFS there is no need for this program and it can be
disabled. The statd (or rpc.statd) program is often started in the
system initialisation scripts (such as /etc/rc* or /etc/rc*.d/*).
If you do not require statd it should be commented out from the
initialisation scripts. In addition, any currently running statd
should be identified using ps(1) and then terminated using kill(1).
...........................................................................
Appendix A Vendor information
The following information regarding this vulnerability for specific vendor
versions of statd has been made available to AUSCERT. For additional
information, sites should contact their vendors directly.
BSDI
====
No versions of BSD/OS are vulnerable to this problem.
Digital Equipment Corporation
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DIGITAL UNIX V4.0 thru V4.0c
At the time of writing this document, patches (binary kits) are in progress
and final testing has been completed. Distribution of the fix for this
problem is expected to begin soon. Digital will provide notice of the
completion/availability of the patches through AES services (WEB, DIA,
DSNlink) and be available from your normal Digital Support channel.
DIGITAL EQUIPMENT CORPORATION 12/97
Hewlett Packard
===============
This problem is in the investigation process.
IBM Corporation
===============
AIX 3.2 and 4.1 are vulnerable to the statd buffer overflow. However,
the buffer overflow described in this advisory was fixed when the APARs
for CERT CA-96.09 was released. See the appropriate release below to
determine your action.
AIX 3.2
-------
Apply the following fix to your system:
APAR - IX56056 (PTF - U441411)
To determine if you have this PTF on your system, run the following
command:
lslpp -lB U441411
AIX 4.1
-------
Apply the following fix to your system:
APAR - IX55931
To determine if you have this PTF on your system, run the following
command:
instfix -ik IX55931
Or run the following command:
lslpp -h bos.net.nfs.client
Your version of bos.net.nfs.client should be 4.1.4.7 or later.
AIX 4.2
-------
No APAR required. Fix already contained in the release.
APARs may be ordered using Electronic Fix Distribution (via
FixDist) or from the IBM Support Center. For more information on
FixDist, reference URL:
http://service.software.ibm.com/aixsupport/
or send e-mail to aixservat_private with a subject of
"FixDist".
IBM and AIX are registered trademarks of International Business
Machines Corporation.
The NetBSD project
==================
NetBSD is not vulnerable to the statd buffer overflow. It does not ship
with NFS locking programs (statd/lockd).
Red Hat Linux
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Red Hat Linux is not vulnerable to the statd buffer overflow. No versions
of Red Hat Linux include statd in any form.
Sun Microsystems
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The statd vulnerability has been fixed by the following patches:
SunOS version Patch Id
------------- --------
5.5.1 104166-02
5.5.1_x86 104167-02
5.5 103468-03
5.5_x86 103469-03
5.4 102769-04
5.4_x86 102770-04
4.1.4 102516-06
4.1.3_U1 101592-09
SunOS 5.6 and 5.6_x86 are not vulnerable to this problem.
The vulnerability described in this advisory is not the same as that
described in Sun Security Bulletin #135.
Sun recommended and security patches (including checksums) are available from:
http://sunsolve.sun.com/sunsolve/pubpatches/patches.html
AUSCERT maintains a local mirror of Sun recommended and security
patches at:
ftp://ftp.auscert.org.au/pub/mirrors/sunsolve1.sun.com/
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AUSCERT thanks Peter Marelas (The Fulcrum Consulting Group), Tim MacKenzie
(The Fulcrum Consulting Group) and CERT/CC for their assistance in the
preparation of this advisory.
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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/)
CERT/CC Contact Information
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Email certat_private
Phone +1 412-268-7090 (24-hour hotline)
CERT personnel answer 8:30-5:00 p.m. EST(GMT-5) / EDT(GMT-4)
and are on call for emergencies during other hours.
Fax +1 412-268-6989
Postal address
CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890
USA
Using encryption
We strongly urge you to encrypt sensitive information sent by email. We can
support a shared DES key or PGP. Contact the CERT/CC for more information.
Location of CERT PGP key
ftp://info.cert.org/pub/CERT_PGP.key
Getting security information
CERT publications and other security information are available from
http://www.cert.org/
ftp://info.cert.org/pub/
CERT advisories and bulletins are also posted on the USENET newsgroup
comp.security.announce
To be added to our mailing list for advisories and bulletins, send
email to
cert-advisory-requestat_private
In the subject line, type
SUBSCRIBE your-email-address
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Copyright 1997 Carnegie Mellon University. Conditions for use, disclaimers,
and sponsorship information can be found in
http://www.cert.org/legal_stuff.html and ftp://ftp.cert.org/pub/legal_stuff .
If you do not have FTP or web access, send mail to certat_private with
"copyright" in the subject line.
*CERT is registered in the U.S. Patent and Trademark Office.
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This file: ftp://info.cert.org/pub/cert_advisories/CA-97.26.statd
http://www.cert.org
click on "CERT Advisories"
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Revision history
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