Worm.VBS.AUTORUN.BKL

 Analysis by: John Donnie Celestre

 ALIASES:

Worm:VBS/Autorun.T (MICROSOFT); VBS/AutoRun.BQ worm (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

8,432 bytes

File Type:

VBS

Memory Resident:

Yes

Initial Samples Received Date:

27 Jun 2019

Arrival Details

This Worm 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 and executes them:

  • %Windows%\:Microsoft Office Update for Windows XP.sys
  • %User Profile%\Documents\database.mdb

(Note: %Windows% is the Windows folder, where it usually is C:\Windows 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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It drops the following files:

  • %User Temp%\auto.exe
  • %User Temp%\rad{5 random chars}.tmp
  • %User Temp%\v.doc
  • %User Temp%\Yuyun.Q

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

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
Explorer = Wscript.exe //e:VBScript "%User Profile%\Documents\database.mdb"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WinUpdate = Wscript.exe //e:VBScript "%Windows%\:Microsoft Office Update for Windows XP.sys"

Other System Modifications

This Worm modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistrytools = 1

Propagation

This Worm drops the following copy of itself in all physical and removable drives:

  • Thumbs.db

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It creates shortcut files (.LNK) disguised as folders or files located on the affected drives pointing to the malware copy.

Other Details

This Worm does the following:

  • It drops the following files on the first day of the month of January, April, July and October:
    • {Infected Folder Path}\\Baca AQ.rtf
    • {Infected Folder Path}\\My name is Yuyun.rtf
  • It creates folders randomly using the following names pointing to the malware copy:
    • "DataQ"
    • "Download"
    • "Game"
    • "New Folder"
    • "New Harry Potter and..."
    • "Rahasia"
    • "SuratQ"
    • "Zvnita"
  • If its the first day of the month it creates the following registries:
    • RegKey: "HKCR\CLSID\{11111111-2222-3333-4444-555555555555}\"
      RegValue: "Yuyun_Cantix"
    • RegKey: "HKCR\CLSID\{11111111-2222-3333-4444-555555555555}\DefaultIcon\"
      RegValue: "shell32.dll,48"
    • RegKey: "HKCR\CLSID\{11111111-2222-3333-4444-555555555555}\ShellFolder\Attributes",
      RegValue: 0
    • RegKey: "HKLM\Software\Microsoft\Windows\CurrentVersion\explorer\Desktop\NameSpace\{11111111-2222-3333-4444-555555555555}\"
      RegValue: ""

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.200.02

FIRST VSAPI PATTERN DATE:

27 Jun 2019

VSAPI OPR PATTERN File:

15.201.00

VSAPI OPR PATTERN Date:

28 Jun 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

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
    • Explorer = Wscript.exe //e:VBScript "%User Profile%\Documents\database.mdb"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • WinUpdate = Wscript.exe //e:VBScript "%Windows%\:Microsoft Office Update for Windows XP.sys"

Step 5

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_CLASSES_ROOT\CLSID\{11111111-2222-3333-4444-555555555555}
    • Yuyun_Cantix
  • In HKEY_CLASSES_ROOT\CLSID\{11111111-2222-3333-4444-555555555555}\DefaultIcon
    • shell32.dll,48
  • In HKEY_CLASSES_ROOT\CLSID\{11111111-2222-3333-4444-555555555555}\ShellFolder\Attributes
    • 0
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\explorer\Desktop\NameSpace\{11111111-2222-3333-4444-555555555555}
    • ""

Step 6

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware. Screen reader support enabled.

Step 7

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.
  • %User Temp%\auto.exe
  • %User Temp%\rad{5 random chars}.tmp
  • %User Temp%\v.doc
  • %User Temp%\Yuyun.Q
  • %Windows%\:Microsoft Office Update for Windows XP.sys
  • %User Profile%\Documents\database.mdb
  • {Infected Folder Path}\\Baca AQ.rtf
  • {Infected Folder Path}\\My name is Yuyun.rtf

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.VBS.AUTORUN.BKL. 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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