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<p>The CERT Coordination Center publishes incident notes to provide
information about incidents to the Internet community.

<h2>911 Worm</h2>

Date: April 4, 2000<br/>
<hr/><br/>
<h3>Overview</h3>
<p>
A worm with variants known as "chode," "foreskin," "dickhair",
"firkin," or "911" has received some attention over the last week. The
National Infrastructure Protection Center issued a bulletin regarding
this worm, available at

<ul>
<a href="http://www.nipc.gov/nipc/advis00-038.htm">http://www.nipc.gov/nipc/advis00-038.htm</a>
</ul>
<p>This worm spreads by taking advantage of unprotected Windows
shares. For more information on a similar problem and relevant
solutions, please see

<ul>
<a href="http://www.cert.org/incident_notes/IN-2000-02.html">http://www.cert.org/incident_notes/IN-2000-02.htm</a>
</ul>
<p>
<h3>Description</h3>
<p>
<p>
The "chode" worm affects Windows 98 systems with unprotected
shares. It does not function properly on Windows NT systems. We have
not completed testing on Windows 95 systems or Windows 2000 systems.

<p>
As of this writing, CERT/CC has not received any direct reports of
systems infected with this worm, though we have received a small
number of second-hand reports.

<p>The worm consists of several batch files, and it takes the
following steps.

<p>CHODE.BAT calls RANDOM.BAT, which picks a target network and
initial host from a set of predefined networks.

<p>Once RANDOM.BAT picks an initial machine, CHODE.BAT increments over
the addresses, and for each address it
<ul>
<li>pings a machine and listens for an answer</li>
<li>on machines that answer the ping, looks for any shares using "net view \\<ip-addr>"</ip-addr></li>
<li>tries to map the C drive on any machine with shares using "net use
/yes j: \\<ip-addr>\c" </ip-addr></li>
<li>looks for j:\windows\win.com</li>
</ul>
<p>If it maps C and finds win.com, it then
<ul>
<li>checks for and deletes instances of "foreskin"</li>
<li>checks for and deletes instances of "mstum.pif"</li>
<li>checks for and deletes instances of "dickhair"</li>
<li>checks for instances of chode</li>
</ul>
<p>If chode is not found, it begins the process of trying to
infect/replicate. It
<ul>
<li>makes the directory j:\zx</li>
<li>copies test.txt to j:\zx\test.txt</li>
</ul>
<p>If the copy is successful, it 
<ul>
<li>deletes the zx directory</li>
<li>makes the directory j:\progra~1/chode</li>
<li>sets chode hidden using "attrib j:\progra~1\chode +h"</li>
<li>copies all chode files to j: using "copy /y c:\progra~1\chode\*.*
j:\progra~1\chode"</li>
</ul>
<p>It then selects a random number based on the time. During this
process, it creates a file called "cu##ent.bat", a file called "current.bat",
and an environment variable called "time".

<p>Based on the random number, it appends a file named "chocher.bat"
to autoexec.bat with probability 1/10. The new autoexec.bat (with
chocher.bat appended) then

<ul>
<li>calls 911 with a probability of 3/6, attempting to use each of COM1
through COM4</li>
<li>formats D,E,F,G,H drives, issues the message <i>tHE cHOdE gOTcHA yOu
sTUpID mOThER fUCKeR!!!!!!!!!!!!!!</i>, and then formats the C drive, all with probability 1/6</li>
</ul>
<p>Chode then copies ashield.pif, netstat.pif, and winsock.vbs to the
startup folder on the victim machine. When Windows next starts on the
victim machine, these files begin the process again.

<p>The winsock.vbs file then deletes all files on the C drive on the
19th day of the month. 

<p>The initiating machine then starts again with a new IP address.
 
<p>We encourage you to read <a href="http://www.cert.org/incident_notes/IN-2000-02.html">CERT
Incident Note IN-2000-02</a> for
information on general solutions to the problem of unprotected Windows
shares.

<p>One notable variant (foreskin) of the worm described in this
document randomly copies one of a set of batch files (named A.BAT,
B.BAT, C.BAT...J.DAT) to a file called MSTUM.BAT. Other variants named
dickhair and firkin are similar.

<h3>Other information</h3>
Additional information about this and similar viruses and worms is  available at 

<ul>
<li><a href="http://www.antivirus.com/pc-cillin/vinfo/virusencyclo/default5.asp?VName=BAT_CHODE911">http://www.antivirus.com/pc-cillin/vinfo/virusencyclo/default5.asp?VName=BAT_CHODE911</a></li>
<li><a href="http://vil.mcafee.com/dispVirus.asp?virus_k=98557">http://vil.mcafee.com/dispVirus.asp?virus_k=98557</a></li>
<li><a href="http://www.sarc.com/avcenter/venc/data/bat.chode.worm.html">http://www.sarc.com/avcenter/venc/data/bat.chode.worm.html</a></li>
<li><a href="http://www.sans.org/newlook/alerts/911worm.htm">http://www.sans.org/newlook/alerts/911worm.htm</a></li>
<li><a href="http://www.sophos.com/virusinfo/analyses/911a.html">http://www.sophos.com/virusinfo/analyses/911a.html</a></li>
<li><a href="http://www.sophos.com/virusinfo/analyses/911b.html">http://www.sophos.com/virusinfo/analyses/911b.html</a></li>
</ul>
<p>
<b>Author</b>: Shawn Hernan<br/>
<p><!--#include virtual="/include/footer_nocopyright.html" --> </p>
<p>Copyright 2000 Carnegie Mellon University.</p>
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