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                               A D V I S O R Y

                                 FA-98.09
******************************************************************************
Topic: Attacks involving the rpc.stad vulnerability
Source: CERT/CC

Creation Date: February 13, 1998
Last Updated: February 13, 1998


To aid in the wide distribution of essential security information,
FedCIRC is forwarding the following information from CERT/CC Summary
CS-98.01 (Special Edition). FedCIRC urges you to act on this
information as soon as possible.

If you have any questions, please contact FedCIRC:

        Telephone:      +1 888 282 0870
        Email:          fedcirc@fedcirc.gov



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CERT* Summary CS-98.01 - SPECIAL EDITION
February 13, 1998


This special edition of the CERT Summary highlights increasing attacks
involving a vulnerability in rpc.statd, also known as statd on some systems.

Past CERT Summaries are available from 
     ftp://ftp.cert.org/pub/cert_summaries/

- ---------------------------------------------------------------------------

Current activity relating to rpc.statd
- --------------------------------------

This special edition of the CERT Summary reports increasing attacks involving
a vulnerability in rpc.statd, also known as statd on some systems. A
description of this vulnerability and corrective actions can be found in

        http://www.cert.org/pub/advisories/CA-97.26.statd.html 

The vulnerability allows a remote attacker to gain root access.  

WARNING: In some cases, intruders have downloaded and installed a vendor patch
         designed to fix this vulnerability after they compromise the
         system. If the patch has been applied on your system, you should
         verify who installed it. If the patch has been installed and
         installation was not done by you or another administrator, you may
         have suffered a root compromise.

It appears that intruders are using automated techniques to identify
vulnerable systems. On compromised machines, intruders have installed suid
root shells, allowing for subsequent root access from non-privileged
accounts. In addition, intruders can install Trojan horse versions of utility
programs like ps, ls, netstat, or find, making it difficult to detect the
intruders' activity.


Checking for signs of intrusion
- -------------------------------

We encourage sites to check for signs that intruders may have attempted to
compromise your machines by exploiting this vulnerability. Sites can do this
by examining your firewall or network monitor (such as argus -
ftp://ftp.net.cmu.edu/pub/argus-1.5/) logs looking for unexpected connections
to port 111, the port normally used by the portmapper or rpcbind. You should
also look for connections to the port used by statd which can be found with

        rpcinfo -p | sed -n -e 1p -e /status/p

Note that each time a system is rebooted, the port assigned to statd
changes. This means that the port in use when you run the rpcinfo program may
be different from the port the intruders used if a machine has been rebooted.

You should also examine logs on individual machines. Unusual syslog
entries for statd may also indicate an intrusion attempt or an actual
compromise.

Also, on some older unpatched Sun systems, the rpcbind program may
listen on a port different than port 111. We encourage you to correct
this condition using the steps outlined in

        ftp://ftp.cert.org/pub/cert_bulletins/VB-97.03.sun

If you discover that your site has been probed for this vulnerability,
we encourage you to check your systems for signs of compromise using
our Intruder Detection Checklist, available at

        ftp://ftp.cert.org/pub/tech_tips/intruder_detection_checklist

Because an intruder may have installed a patch that corrects this problem,
simply checking for the existence of the patch is not enough. This checklist
will help you methodically check your systems for signs of compromise. It also
includes pointers to other resources and suggestions on how to proceed in the
event of a compromise.

In many cases, intruders have installed packet sniffers on compromised
machines. These sniffers, used to collect account names and passwords, are
frequently installed as part of a widely-available toolkit that also replaces
common system files with Trojan horse programs. The Trojan horse binaries (du,
ls, ifconfig, netstat, login, ps, etc.)  hide the intruders' files and sniffer
activity on the system on which they are installed. These packet sniffers
also frequently hide their logs in system directories such as /usr/include or
/dev/ptyxx.

For further information and methods for detecting packet sniffers and
Trojan horse binaries, see the following files:

 ftp://ftp.cert.org/pub/cert_advisories/CA-94:01.network.monitoring.attacks

 ftp://ftp.cert.org/pub/cert_advisories/CA-94:05.MD5.checksums


Recovering from a compromise and protecting your system
- -------------------------------------------------------

If you discover that you have suffered a root compromise, we encourage you to
recover by taking the steps outlined in

       ftp://ftp.cert.org/pub/tech_tips/root_compromise 

This document contains information to help you recover from the incident and
offers pointers to other resources to help you secure your systems against
future compromise.

As is good practice with any service, if you do not use NFS you should
disable it. If you need to use NFS, you should block NFS traffic at
your router or firewall if possible. We recommend a conservative,
minimalist approach to network filtering in which only those services
specifically required are permitted, while all other services are
denied.


Scans in addition to the rpc.statd probes
- ----------------------------------------- 

We have continued to see similar scans of the Internet looking for other
well-known vulnerabilities, and many of these scans have led to root
compromises. Most recently, intruders have launched widespread scans looking
for vulnerable IMAP server. For more information, please see


        ftp://ftp.cert.org/pub/cert_summaries/CS-97.06 
        ftp://ftp.cert.org/pub/cert_summaries/CS-97.05
        ftp://ftp.cert.org/pub/cert_summaries/CS-97.04
        ftp://ftp.cert.org/pub/cert_summaries/CS-97.03
        ftp://ftp.cert.org/pub/cert_summaries/CS-97.02
 
In addition, widespread scans looking for other NFS-related
vulnerabilities have occurred in the past. For more information, please
see
 
        ftp://ftp.cert.org/pub/cert_summaries/CS-96.01
 

Contacting other sites
- ----------------------

If, during the course of your investigation, you discover evidence
indicating that other sites are involved, we encourage you to contact
those sites directly and to include cert@cert.org on the CC line of
any messages you exchange. The will help us to better understand the
nature, scope, and frequency of security incidents on the Internet,
while allowing affected sites to establish direct contact. In
addition, we may be able to relate the activity to other activity that
has been reported to us.


Reporting to your incident response team
- ---------------------------------------- 

If you are represented by another incident response team in the Forum
of Incident Response and Security Teams (FIRST), we encourage you to
follow up with that team. More information about FIRST can be found at
 
        http://www.first.org/
 

- ---------------------------------------------------------------------------
How to Contact the CERT Coordination Center

Email    cert@cert.org 

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

To be added to our mailing list for CERT advisories and bulletins, send your
email address to 
        cert-advisory-request@cert.org
In the subject line, type
        SUBSCRIBE your-email-address

CERT advisories and bulletins are posted on the USENET news group
         comp.security.announce

CERT publications, information about FIRST representatives, and other
security-related information are available for anonymous FTP from
        http://www.cert.org/
        ftp://ftp.cert.org/pub/

If you wish to send sensitive incident or vulnerability information to CERT
staff by electronic mail, we strongly advise you to encrypt your message.
We can support a shared DES key or PGP. Contact the CERT staff for more
information. 

Location of CERT PGP key
         ftp://ftp.cert.org/pub/CERT_PGP.key

- ---------------------------------------------------------------------------

Copyright 1998 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 cert@cert.org with
"copyright" in the subject line.
 
* CERT is registered in the U.S. Patent and Trademark Office.







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The National Institute of Standards and Technology (NIST) has
established a Federal Computer Incident response Capability (FedCIRC)
to assist federal civilians agencies in their incident handling
efforts by providing proactive and reactive computer security related
services.  FedCIRC is a partnership among NIST, the Computer Incident
Advisory Capability (CIAC), and the CERT* Coordination Center
(CERT/CC). 

If you believe that your system has been compromised, please contact
FedCIRC: 

        Telephone:      +1 888 282 0870
        Email:          fedcirc@fedcirc.gov
        Web Server:     http://www.fedcirc.gov/

* Registered in U.S. Patent and Trademark Office
 
The CERT Coordination Center is part of the Software Engineering
Institute.  The Software Engineering Institute is sponsored by the
U.S. Department of Defense.

CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.
 
This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
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