WORM_EMUDBOT.DJ

 Analysis by: David John Agni

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

311,808 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Jan 2015

Arrival Details

This worm arrives via removable drives.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This worm drops the following files:

  • {Removable Drive Letter}:\autorun.bat
  • {Removable Drive Letter}:\autorun.inf
  • {Removable Drive Letter}:\autorun.vbs

It drops and executes the following files:

  • %User Temp%\{Random Letters}.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Autostart Technique

This worm registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\vaaroartzu
DisplayName = "akqrselrzl"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\vaaroartzu
ImagePath = "%User Temp%\{Random Letters}.exe -svc"

Other System Modifications

This worm adds the following registry keys as part of its installation routine:

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\P3P
(Default) = "(value not set)"

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • {Removable Drive Letter}:\recycle.exe

Other Details

This worm connects to the following possibly malicious URL:

  • http://{BLOCKED}k.{BLOCKED}here.com/mars/iLog.php?dl=5.9&log=Loader:%20508%5eBB

  SOLUTION

Minimum Scan Engine:

9.700

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Identify and terminate files detected as WORM_EMUDBOT.DJ

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services
    • vaaroartzu
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • P3P

Step 5

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\{Random Letters}.exe
  • {Removable Drive Letter}:\autorun.vbs
  • {Removable Drive Letter}:\autorun.bat
  • {Removable Drive Letter}:\recycle.exe

Step 6

Search and delete AUTORUN.INF files created by WORM_EMUDBOT.DJ that contain these strings

[ Learn More ]
  • [AutoRun]
  • open=autorun.bat
  • shellexecute=autorun.bat
  • shell\Auto\command=autorun.bat
  • shell\explore\Command=autorun.bat
  • shell=auto
  • Action=USB Drive
  • Label=USB Drive
  • UseAutoPlay=0

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_EMUDBOT.DJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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