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WORM_COPYKAT.B

November 29, 2016
 Analysis by: Byron Jon Gelera
 ALIASES:

Trojan.Win32.Vilsel.bozg (Kaspersky); Worm:Win32/VB.VX (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via removable drives, Downloaded from the Internet, Dropped by other malware


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.

It creates registry entries to enable its automatic execution at every system startup.

  TECHNICAL DETAILS

File Size:

331,776 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Nov 2016

Payload:

Drops files, Modifies system registry

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:

  • %User Startup%\Angel2.exe
  • %System Root%\window.exe
  • {Removable Drive Letter}:\Angel2.exe
  • %User Profile%\Documents\MyDocuments.exe
  • %Favorites%\Fonts.exe
  • %Application Data%\Microsoft\Windows\Recent\Recycle Bin.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Favorites% is the Favorites folder, where it usually is C:\Documents and Settings\{user name}\Favorites on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Favorites 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.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
gpmce = \Angel2.exe

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
gpmce = \Angel2.exe

Other System Modifications

This worm modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
search page = www.booble.com

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
start page = "www.gpmce.net"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
DisableThumbnailCache = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
system
DisableTaskMgr = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
system
DisableRegistryTools = "1"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System
disableCMD = "2"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}
LocalizedString = "@%SystemRoot%\system32\SHELL32.dll,-8964"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}
LocalizedString = "@%SystemRoot%\system32\shell32.dll,-9216"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}\DefaultIcon
(Default) = "%SystemRoot%\System32\shell32.dll,31"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
(Default) = "%SystemRoot%\Explorer.exe,0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
full = "%SystemRoot%\Explorer.exe,0"

Propagation

This worm searches for folders in all physical and removable drives then drops copies of itself inside the folder as {folder name}.EXE.

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

12.928.04

FIRST VSAPI PATTERN DATE:

29 Nov 2016

VSAPI OPR PATTERN File:

12.929.00

VSAPI OPR PATTERN Date:

30 Nov 2016

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

Restart in Safe Mode

[ Learn More ]

Step 4

Restore modified and/or deleted registry value/s using this VBScript

To restore the modified and/or deleted registry value/s:

  1. Open Notepad.
    » For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Open input box, type notepad then press Enter.
    » For Windows Vista, Windows 7 and Windows Server 2008 users, click Start, type notepad in the Search input field then press Enter.
    » For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Run, type notepad, then press Enter.
  2. Copy and paste the following script:
  3. Save this file as C:\RESTORE.VBS.
  4. Run C:\RESTORE.VBS.
    » For Windows 2000, XP, and Server 2003 users, click Start>Run. In the Open input box, type C:\RESTORE.VBS then press Enter.
    » For Windows Vista, Windows 7 and Windows Server 2008 users, click Start, type C:\RESTORE.VBS in the Search input field then press Enter.
    » For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Run, type C:\RESTORE.VBS, then press Enter.

Step 5

Delete these registry values

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • gpmce = \Angel2.exe
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • gpmce = \Angel2.exe

Step 6

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: start page = "www.gpmce.net"
      To: start page = {user defined}
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: search page = "www.booble.com"
      To: search page = {user defined}

Step 7

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