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TROJ_DROPPER.WPZ

October 13, 2012
 ALIASES:

Worm:Win32/Rebhip.A (Microsoft); Trojan-Dropper.Win32.Injector.flnp (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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

It disables Task Manager, Registry Editor, and Folder Options.

  TECHNICAL DETAILS

File Size:

1,060,864 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

26 Aug 2012

Arrival Details

This Trojan 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 Trojan drops the following copies of itself into the affected system:

  • %System%\AnubisCheck\anubischks.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It creates the following folders:

  • %System%\AnubisCheck
  • %User Profile%\Application Data\68AD0FD0

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
anubischks = "%System%\AnubisCheck\anubischks.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
anubischks = "%System%\AnubisCheck\anubischks.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

HKEY_CURRENT_USER\SOFTWARE\c2

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
anubischk = "%System%\AnubisCheck\anubischks.exe"

HKEY_CURRENT_USER\Software\c2
FirstExecution = "25/08/2012 -- 17:37"

HKEY_CURRENT_USER\Software\c2
NewIdentification = "c2"

HKEY_CURRENT_USER\Software\c2
NewGroup = [REG_EXPAND_SZ, value: ]

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
anubischk = "%System%\AnubisCheck\anubischks.exe"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\Wilbert2.txt
  • %System Root%\default.html
  • %User Profile%\68AD0FD0\ak.tmp
  • %User Profile%\Application Data\Wilbert-wchelper.dll
  • %User Temp%\Wilbert7
  • %User Temp%\Wilbert8
  • %User Startup%\anubischks.exe

(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, XP, and Server 2003.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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.

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\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\SOFTWARE
    • c2

Step 5

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • anubischks = "%System%\AnubisCheck\anubischks.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • anubischks = "%System%\AnubisCheck\anubischks.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • anubischk = "%System%\AnubisCheck\anubischks.exe"
  • In HKEY_CURRENT_USER\Software\c2
    • FirstExecution = "25/08/2012 -- 17:37"
  • In HKEY_CURRENT_USER\Software\c2
    • NewIdentification = "c2"
  • In HKEY_CURRENT_USER\Software\c2
    • NewGroup = [REG_EXPAND_SZ, value: ]

Step 6

Search and delete these files

[ Learn More ]
There may be some component 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%\Wilbert2.txt
  • %System Root%\default.html
  • %User Profile%\68AD0FD0\ak.tmp
  • %User Profile%\Application Data\Wilbert-wchelper.dll
  • %User Temp%\Wilbert7
  • %User Temp%\Wilbert8
  • %User Startup%\anubischks.exe

Step 7

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System%\AnubisCheck
  • %User Profile%\Application Data\68AD0FD0

Step 8

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