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Date discovered:30/08/2006
In the wild:Yes
Reported Infections:Low
Distribution Potential:Medium
Damage Potential:Low to medium
Static file:Yes
File size:89.829 Bytes
MD5 checksum:029c3f07c57a67df871153701abbe23d
VDF version:
IVDF version: - Thursday, August 31, 2006

 General Method of propagation:
   • Email

   •  Kaspersky: Email-Worm.Win32.Warezov.h
   •  TrendMicro: WORM_STRATION.BR
   •  Eset: Win32/Stration.T

Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003

Side effects:
   • Downloads a malicious file
   • Drops a malicious file
   • Uses its own Email engine
   • Registry modification

Right after execution the following information is displayed:

 Files It copies itself to the following location:
   • %WINDIR%\rsmb.exe

The following files are created:

– A file that contains collected email addresses:
   • %WINDIR%\rsmb.wax

%malware execution directory%\%two-digit random character string%.tmp
%WINDIR%\rsmb.dll Used to hide a process. Detected as: WORM/Stration.5

It tries to download a file:

– The location is the following:
At the time of writing this file was not online for further investigation.

 Registry The following registry key is added in order to run the process after reboot:

– HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   • "rsmb"="%WINDIR%\rsmb.exe s"

 Email It contains an integrated SMTP engine in order to send emails. A direct connection with the destination server will be established. The characteristics are described in the following:

The sender address is spoofed.

– Email addresses found in specific files on the system.
– Email addresses gathered from WAB (Windows Address Book)

One of the following:
   • Error
   • picture
   • Status
   • Good day
   • Mail Delivery System
   • Mail Transaction Failed

The body of the email is one of the lines:
   • The message contains Unicode characters and has been sentas a binary attachment.
   • The message cannot be represented in 7-bit ASCII encodingand has been sent as a binary attachment
   • Mail transaction failed. Partial message is available.

The filename of the attachment is constructed out of the following:

–  It starts with one of the following:
   • test
   • file
   • doc
   • document
   • message

    Continued by one of the following fake extensions:
   • dat
   • log
   • msg
   • txt

    The file extension is one of the following:
   • exe
   • cmd
   • pif

The attachment is a copy of the malware itself.

The email looks like the following:

 Mailing Search addresses:
It searches the following files for email addresses:
   • xml; xls; wsh; wab; uin; txt; tbb; stm; shtm; sht; php; oft; ods; nch;
      msg; mmf; mht; mdx; mbx; jsp; html; htm; eml; dhtm; dbx; cgi; cfg;
      asp; adb

 File details Programming language:
The malware program was written in MS Visual C++.

Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with the following runtime packer:
   • MEW

Description inserted by Irina Boldea on Thursday, November 23, 2006
Description updated by Irina Boldea on Thursday, November 23, 2006

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