Operating System:


05 September 1999

Protect yourself against future threats.


              AUSCERT External Security Bulletin Redistribution
                    ESB-1999.130 -- CERT Summary CS-99-03
                                CERT Summary
                              6 September 1999


The CERT Coordination Centre has released the following summary concerning
types of attacks currently being reported. AusCERT has noted similar trends
reported within Australia and New Zealand.

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CERT Summary CS-99-03

   August 31, 1999
   Each quarter, the CERT® Coordination Center (CERT/CC) issues the CERT
   summary to draw attention to the types of attacks reported to our
   incident response team, as well as other noteworthy incident and
   vulnerability information. The summary includes pointers to sources of
   information for dealing with the problems.
   Past CERT summaries are available from

   On October 4, 1999, the current PGP key for the CERT/CC will be
   replaced with a new PGP key. For more information, see
New "CERT/CC Current Activity" Web Page

   The CERT/CC Current Activity web page is a regularly updated summary
   of the most frequent, high-impact types of security incidents and
   vulnerabilities currently being reported to the CERT/CC. It is
   available from
   The information on the Current Activity page will be reviewed and
   updated as reporting trends change.
Recent Activity

   Since the last CERT summary, issued in May 1999 (CS-99-02), we have
   noted several vulnerabilities in RPC services, and we have analyzed
   and published information regarding the ExploreZip worm. We also
   continue to see widespread scans for known vulnerabilites.
   Protect your systems. Use current software versions, install patches
   as they become available, and update your scanning tools and
   anti-virus software with the latest virus signatures or definitions.
   Be cautious of unsolicited documents or executable programs received
   in electronic mail. Be wary of software that comes from untrusted
    1. RPC Vulnerabilities
       We have received many reports of exploitations involving three RPC
       vulnerabilties. Such exploitations can lead to root compromise on
       systems that implement these RPC services. Analysis has shown that
       similar artifacts have been found on compromised systems. The
       vulnerable services are
       Remote and local users can execute arbitrary code with the
       privileges of the rpc.cmsd daemon, typically root. This
       vulnerability is being exploited in a significant number of
       incidents reported to the CERT/CC. For more information see
        CERT Incident Note 99-04
            CERT Advisory CA-99-08
       statd and automoutd
       Vulnerabilities in these two services are being used together by
       intruders to gain access to vulnerable systems. The first
       vulnerability is in rpc.statd, a program used to communicate state
       changes among NFS clients and servers. The second vulnerability is
       in automountd, a program used to automatically mount certain types
       of file systems. The vulnerability in rpc.statd may allow a remote
       intruder to call arbitrary RPC services with the privileges of the
       rpc.statd process, typically root. The vulnerablility in
       automountd may allow a local intruder to execute arbitrary
       commands with the privileges of the automountd service.
       By combining attacks exploiting these two vulnerabilities, a
       remote intruder is able to execute arbitrary commands with the
       privileges of the automountd service. For more information see
        CERT Incident Note 99-04
            CERT Advisory CA-99-05
       The ToolTalk database server (rpc.ttdbserverd) is an ONC RPC
       service that 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 CDE
       (Common Desktop Environment), which is a standard component of
       many commercial Unix operating systems.
       Due to an implementation fault in rpc.ttdbserverd, it is possible
       for a malicious remote client to formulate an RPC message that can
       lead to a buffer overflow. This buffer overflow can result in an
       attacker gaining total control of the ttdbserver process. An
       intruder may be able to use this control to gain root-level
        CERT Incident Note 99-04
            CERT Advisory CA-98-11
    2. Virus and Trojan Horse Activity
       We continue to see reports of virus activity. Current versions of
       anti-virus software can help to protect your systems from these
       It is important to take great caution with any email or Usenet
       attachments that contain executable content. If you receive a
       message containing attachments, scan the message file with
       anti-virus software before you open or run the file. Doing this
       does not guarantee that the contents of the file are safe, but it
       lowers your risk of virus infection by checking for viruses and
       Trojan horses that your scanning software can detect.
       The ExploreZip program is a Trojan horse affecting Windows
       95/98/NT systems. It modifies system files and destroys files. For
       ExploreZip to work, a person must open or run an infected email
       attachment, which allows the program to install a copy of itself
       on the victim's computer and enables further propagation.
       ExploreZip may also behave as a worm, propagating to other network
       machines without human interaction. For more information see
        CERT Advisory CA-99-06 ExploreZip Trojan Horse Program
            CERT Advisory CA-99-02 Trojan Horses
    3. Continued Widespread Scans
       We are still receiving daily reports of intruders using tools to
       scan networks for multiple vulnerabilities. Intruder scanning
       tools continue to become more sophisticated, varying from scripted
       tools and stealth scanning techniques to a tool that incorporates
       probes for known vulnerabilities, remote operating system
       identification, and automated exploitation attempts. For more
       information, see
        "sscan" Scanning Tool
            Automated Scanning and Exploitation
            Probes with Spoofed IP Addresses
            Advanced Scanning
            New Tools Used for Widespread Scans
       The most frequent reports involve well-known vulnerabilities in
       mountd, IMAP, POP3, and several RPC services. These services are
       installed and enabled by default in some operating systems. See
       the following advisories for more information:
        sunrpc (TCP port 111) and mountd (635)
            IMAP (TCP port 143)
            POP3 (TCP port 110)
            DNS (TCP port 53 [domain])
       These scans involve known vulnerabilities for which patches are
       available. Protect your systems by making sure that they are
       properly secured.
What's New and Updated

   Since the last CERT summary, we have developed new and updated
     * Advisories
     * Courses
     * Incident notes
     * Security improvement modules
     * Technical reports
     * Tech tips
     * Virus resources
   There are descriptions of these documents and links to them on our
   "What's New" web page at
   This document is available from:
CERT/CC Contact Information

   Email: cert@cert.org
          Phone: +1 412-268-7090 (24-hour hotline)
          Fax: +1 412-268-6989
          Postal address:
          CERT® Coordination Center
          Software Engineering Institute
          Carnegie Mellon University
          Pittsburgh PA 15213-3890
   CERT personnel answer the hotline 08:00-20:00 EST(GMT-5) / EDT(GMT-4)
   Monday through Friday; they are on call for emergencies during other
   hours, on U.S. holidays, and on weekends.
Using encryption

   We strongly urge you to encrypt sensitive information sent by email.
   Our public PGP key is available from
   If you prefer to use DES, please call the CERT hotline for more
Getting security information

   CERT publications and other security information are available from
   our web site
   To be added to our mailing list for advisories and bulletins, send
   email to cert-advisory-request@cert.org and include SUBSCRIBE
   your-email-address in the subject of your message.
   Copyright 1999 Carnegie Mellon University.
   Conditions for use, disclaimers, and sponsorship information can be
   found in
   * "CERT" and "CERT Coordination Center" are registered in the U.S.
   Patent and Trademark Office.
   Any material furnished by Carnegie Mellon University and the Software
   Engineering Institute is furnished on an "as is" basis. Carnegie
   Mellon University makes no warranties of any kind, either expressed or
   implied as to any matter including, but not limited to, warranty of
   fitness for a particular purpose or merchantability, exclusivity or
   results obtained from use of the material. Carnegie Mellon University
   does not make any warranty of any kind with respect to freedom from
   patent, trademark, or copyright infringement.

Version: 2.6.2


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This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
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the responsibility of each user or organisation, and should be done so in
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NOTE: This is only the original release of the security bulletin.  It will
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the original authors to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:


If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security

Internet Email: auscert@auscert.org.au
Facsimile:	(07) 3365 7031
Telephone:	(07) 3365 4417 (International: +61 7 3365 4417)
		AusCERT personnel answer during Queensland business hours
		which are GMT+10:00 (AEST).
		On call after hours for emergencies.

Version: 2.6.3i
Charset: noconv
Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key