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Virus:TR/Drop.VB.BAK
Date discovered:11/10/2010
Type:Trojan
Subtype:Dropper
In the wild:Yes
Reported Infections:Low to medium
Distribution Potential:Medium
Damage Potential:Low to medium
Static file:Yes
File size:86.016 Bytes
MD5 checksum:6f638a6d41d60c969946e75b7c020018
VDF version:7.10.05.170
IVDF version:7.10.12.171 - Monday, October 11, 2010

 General Methods of propagation:
   • Autorun feature
   • Email
   • Messenger


Aliases:
   •  Mcafee: W32/Autorun.worm.aaj
   •  Kaspersky: Trojan.Win32.VBKrypt.kdk
   •  Bitdefender: Trojan.Dropper.VB.BAK
   •  GData: Trojan.Dropper.VB.BAK


Platforms / OS:
   • Windows 2000
   • Windows XP
   • Windows 2003


Side effects:
   • Drops malicious files
   • Registry modification

 Files It copies itself to the following locations:
   • %TEMPDIR%\1UlaiYla.exe
   • %drive%\1UlaiYla.exe



It deletes the initially executed copy of itself.



The following file is created:

%drive%\Autorun.inf This is a non malicious text file with the following content:
   • %code that runs malware%

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

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • "Windows"="%TEMPDIR%\1UlaiYla.exe"



The following registry key is added:

– [HKLM\Software\Microsoft\Active Setup\Installed Components\
   {36A5A0DB-297E-FDE2-0501-060104070800}]
   • "StubPath"="%TEMPDIR%\1UlaiYla.exe"

 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:


From:
The sender address is spoofed.


To:
– Email addresses found in specific files on the system.


Body:
– Contains HTML code.

The attachment is a copy of the malware itself.

 Messenger It is spreading via Messenger. The characteristics are described below:

– Windows Messenger

The URL then refers to a copy of the described malware. If the user downloads and executes this file the infection process will start again.

 Backdoor Contact server:
All of the following:
   • http://updates-call.com/**********?id=%character string%&co=%character string%&us=%character string%&os=%character string%&vr=%character string%&av&dt
   • http://124.217.253.18/**********?id=%character string%&co=%character string%&us=%character string%&os=%character string%&vr=%character string%&av&dt



Sends information about:
    • Computer name
    • Malware uptime
    • Username
    • Information about the Windows operating system

 Injection – It injects itself as a remote thread into a process.

    Process name:
   • explorer.exe


 Miscellaneous Mutex:
It creates the following Mutex:
   • X00X

 File details Programming language:
The malware program was written in Visual Basic.


Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with a runtime packer.

Description inserted by Petre Galan on Friday, March 18, 2011
Description updated by Petre Galan on Friday, March 18, 2011

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