Published:
04 August 1997
Protect yourself against future threats.
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AUSCERT External Security Bulletin Redistribution
ESB-97.101 -- CERT Summary CS-97.04
5 August 1997
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The CERT Coordination Center has released the following summary highlighting
current large-scale intruder activity attacking a vulnerability in certain
implementations of IMAP. Remote users can obtain root access on systems
running a vulnerable server. They do not need access to an account on
the system to do this.
AUSCERT is seeing similar intruder activity.
AUSCERT released the CERT/CC advisory CA-97.09 as an external security
bulletin which is available from:
ftp://ftp.auscert.org.au/pub/auscert/ESB/ESB-97.042
The following security bulletin is provided as a service to AUSCERT's
members. As AUSCERT did not write this document, AUSCERT has had no
control over its content. As such, the decision to use any or all of this
information is the responsibility of each user or organisation, and should
be done so in accordance with site policies and procedures.
Contact information for CERT/CC is included in the Security Bulletin below.
If you have any questions or need further information, please contact them
directly.
Previous advisories and external security bulletins can be retrieved from:
http://www.auscert.org.au/information/advisories.html
If you believe that your system has been compromised, contact AUSCERT or your
representative in FIRST (Forum of Incident Response and Security Teams).
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 4477
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.
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CERT* Summary CS-97.04 - SPECIAL EDITION
August 4, 1997
This special edition of the CERT Summary highlights large-scale attacks
involving a vulnerability in certain implementations of IMAP. This
vulnerability and corrective actions are described in
ftp://info.cert.org/pub/cert_advisories/CA-97.09.imap_pop
Because attacks have been occurring since the release of this advisory, we
urge you to take immediate action to address this vulnerability.
The vulnerability lies in the implementation of this particular IMAP server,
not with the protocol.
Preliminary data from one current incident indicates that probes were made to
thousands of hosts, and approximately 40% of those hosts appear to be
vulnerable. In addition to this large incident, we have been receiving
numerous reports of root compromises as a result of this vulnerability.
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://info.cert.org/pub/tech_tips/intruder_detection_checklist
This document will help you methodically check your systems for signs of
compromise and offers pointers to other resources and suggestions on how to
proceed in the event of a compromise.
On one machine where large-scale scans were launched, the intruders installed
a Trojan Horse identd server. This Trojan identd allowed intruders to connect
to the identd server and obtain root access. If you are running identd, we
encourage you to verify the integrity of your identd executable with the
distribution.
If you discover that you have suffered a root compromise as a result, we
encourage you to recover by taking the steps outlined in
ftp://info.cert.org/pub/tech_tips/root_compromise
This will help you recover from the incident, and offers pointers to other
resources that may help you secure your systems against future compromise.
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.
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/
Due to the large volume of messages we anticipate, we will not be able to
respond to each report individually. However, your reports will help us
determine the scope of the problem and coordinate activity in response.
Past CERT Summaries are available from
ftp://info.cert.org/pub/cert_summaries/
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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://info.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://info.cert.org/pub/CERT_PGP.key
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Copyright 1997 Carnegie Mellon University
This material may be reproduced and distributed without permission provided
it is used for noncommercial purposes and credit is given to the CERT
Coordination Center.
* Registered U.S. Patent and Trademark Office.
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