TROJ_VB.ATM


 ALIASES:

Trojan Horse (Symantec); Trojan.Win32.VB.cvn (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Generic10.ZYH (AVG)

 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:

61,440 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Jun 2013

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.

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{p6B2445-1963-9142-A0DB-DBDB9E15FB9z}
StubPath = "%System Root%\{malware file name}.exe autorun"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "explorer.exe %System Root%\{malware file name}.exe"

(Note: The default value data of the said registry entry is Explorer.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
AutoRestartShell = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "explorer.exe "

(Note: The default value data of the said registry entry is Explorer.exe.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{p6B2445-1963-9142-A0DB-DBDB9E15FB9z}

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableChangePassword = "ffffffff"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableLockWorkStation = "ffffffff"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "explorer.exe "

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "ffffffff"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Active Setup\Installed Components\{p6B2445-1963-9142-A0DB-DBDB9E15FB9z}

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Identify and delete files detected as TROJ_VB.ATM using either the Startup Disk or Recovery Console

[ 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/spyware.

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\Active Setup\Installed Components
    • {p6B2445-1963-9142-A0DB-DBDB9E15FB9z}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • System

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\Active Setup\Installed Components\{p6B2445-1963-9142-A0DB-DBDB9E15FB9z}
    • StubPath = "%System Root%\{malware file name}.exe autorun"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableChangePassword = "ffffffff"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableLockWorkStation = "ffffffff"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • shell = "explorer.exe "

Step 6

Restore these modified 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 NT\CurrentVersion\Winlogon
    • From: shell = "explorer.exe %System Root%\{malware file name}.exe"
      To: shell = ""Explorer.exe""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: AutoRestartShell = "0"
      To: AutoRestartShell = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: shell = "explorer.exe "
      To: shell = ""Explorer.exe""

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_VB.ATM. 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.

Step 8

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\Software\Microsoft\Active Setup\Installed Components
    • {p6B2445-1963-9142-A0DB-DBDB9E15FB9z}


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