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WORM_DORKBOT.VR

April 14, 2014
 Modified by: Adrian Cofreros
 ALIASES:

Worm:Win32/Dorkbot.I (Microsoft); PWSZbot-FIV!50A159543A3A (McAfee); Trojan.Gen.2 (Symantec); Worm.Win32.Ngrbot.vai (Kaspersky); Trojan.Win32.Agent.adgv (v) (Sunbelt); Trojan horse Inject.CGZR (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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:

164,352 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Apr 2014

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 copies of itself into the affected system:

  • %Application Data%\temp.bin
  • %Application Data%\ScreenSaverPro.scr

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Screen Saver Pro 3.1 = "%Application Data%\ScreenSaverPro.scr"

Propagation

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

  • {removable drive letter}:\ViewFiles.cmd
  • {removable drive letter}:\{random file name}.exe

Other Details

This worm connects to the following possibly malicious URL:

  • http://api.{BLOCKED}ia.com.stcus.ru/icon/n.api
  • http://{BLOCKED}.{BLOCKED}.169.105/3434.exe
  • http://{BLOCKED}.{BLOCKED}.172.15/a33.exe

NOTES:

It connects to the following URL:

  • http://api.wipmania.com/

It drops shortcut (.LNK) files using folder/file names found in removable drives: {removable drive letter}:\{folder/'file name and extension'}.lnk if the folder/file exists.

It then hides the original folder/file tricking users to click .LNK files. This .LNK files point out to a dropped copy of itself in the removable drive.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.350.01

FIRST VSAPI PATTERN DATE:

18 Oct 2013

VSAPI OPR PATTERN File:

10.351.00

VSAPI OPR PATTERN Date:

19 Oct 2013

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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Screen Saver Pro 3.1 = "%Application Data%\ScreenSaverPro.scr"

Step 4

Search and delete these files

[ 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.  
  • {removable drive letter}:\{folder/'file name and extension'}.lnk

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.VR. 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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