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The U.S. Department of Energy
Computer Incident Advisory Center
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ADVISORY NOTICE
The W32.nimda Worm
September 19, 2001 00:00 GMT Number L-144
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PROBLEM: An extremely virulent worm is currently spreading throughout
the Internet. It uses multiple methods of infection to spread
among both Windows server and user machines.
PLATFORM: All Windows platforms including IIS servers and client systems
using web browsers and html enabled mail readers. Of particular
risk are home users who use the html enabled web browsers with
Javascript enabled.
DAMAGE: Compromised machines will attack other machines on the
Internet. Files may be damaged. Network resources will be used
which will slow the Internet.
SOLUTION: Apply patches to uninfected systems, specifically Microsoft
patches MS01-044 and MS01-020. MS01-044 patches IIS servers to
prevent them from being compromised. The MS01-020 patch
protects client browsers and mail readers based on the Internet
Explorer browser. Compromised machines must be pulled off of
the Internet and rebuilt or cleaned with antivirus software as
it becomes available. Note: Rebooting will not clean your
system of this worm.
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VULNERABILITY The risk is HIGH. The worm is rapidly spreading throughout the
ASSESSMENT: Internet.
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LINKS:
CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/l-044.shtml
PATCHES:
http://www.microsoft.com/technet/security/bulletin/ms01-044
http://www.microsoft.com/technet/security/bulletin/ms01-020
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The W32.nimda worm is still being analyzed but we currently see a spread via
e-mail, web pages, and attacks on vulnerable web servers. Web servers are
attacked using multiple, known vulnerabilities such as unicode and directory
traversal. All of these can be patched with the MS01-044 patch set available
from Microsoft. Client systems are attacked by simply opening infected mail
or accessing infected web pages. The vulnerability exploited is that closed
by the MS01-020 patch from Microsoft. The worm also spreads by open shares
between Windows machines.
Infected mail messages contain an attachment named readme.exe. IIS web
servers retrieve admin.dll using tftp. Admin.dll is the same program as
readme.exe. Unique strings detected in the executables and the mail message
includes the following.
boundary="====_ABC1234567890DEF_===="
X-Priority: 3
X-MSMail-Priority: Normal
X-Unsent: 1
--====_ABC1234567890DEF_====
Content-Type: multipart/alternative;
boundary="====_ABC0987654321DEF_===="
--====_ABC0987654321DEF_====
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<HTML><HEAD></HEAD><BODY bgColor=3D#ffffff>
<iframe src=3Dcid:EA4DMGBP9p height=3D0 width=3D0>
</iframe></BODY></HTML>
--====_ABC0987654321DEF_====--
--====_ABC1234567890DEF_====
Content-Type: audio/x-wav;
name="readme.exe"
Content-Transfer-Encoding: base64
Content-ID: <EA4DMGBP9p>
Antivirus vendors are making scanning and cleaning software available.
We will revise this bulletin as more information becomes available.
______________________________________________________________________________
CIAC, the Computer Incident Advisory Center, 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.
CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
Voice: +1 925-422-8193 (7x24)
FAX: +1 925-423-8002
STU-III: +1 925-423-2604
E-mail: ciac@ciac.org
Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.
World Wide Web: http://www.ciac.org/
Anonymous FTP: ftp.ciac.org
PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins. If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.
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
legal liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial products,
process, or service by trade name, trademark, manufacturer, or
otherwise, does not necessarily constitute or imply its endorsement,
recommendation or favoring by the United States Government or the
University of California. The views and opinions of authors expressed
herein do not necessarily state or reflect those of the United States
Government or the University of California, and shall not be used for
advertising or product endorsement purposes.
LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC)
L-134: HP Security Vulnerability in rlpdaemon
L-135: SGI File Globbing Vulnerability in ftpd
L-136: HP-UX Security Vulnerability in PRM
L-137: FreeBSD lpd Remote Root Vulnerability
L-138: Gauntlet Firewall CSMAP and smap/smapd Buffer Overflow Vulnerability
L-139: Microsoft IIS "%u encoding IDS bypass vulnerability"
L-140: Gauntlet Firewall CSMAP and smap/smapd Buffer Overflow Vulnerability
L-141: RSA BSAFE SSL-J 3.x Vulnerability
L-142: RPC Endpoint Mapper Vulnerability
L-143: HP libsecurity Vulnerability
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