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:
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Autostart Technique
This Trojan modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe, %System%\{random}.exe,"
(Note: The default value data of the said registry entry is %System%\userinit.exe,.)
It adds the following Image File Execution Options registry entries to automatically execute itself whenever certain applications are run:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
{application name}
Debugger = "P9KDMF.EXE"
Other System Modifications
This Trojan adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
{application name}
It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
DisableTaskMgr = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
DisableRegedit = "1"
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot\Minimal
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot\Network
Where {application name} may be any of the following:
- msconfig.exe
- regedit.exe
- taskmgr.exe
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}fo.com/04/a.php?id=B0B2D6E3584E49570050&cmd=img
- http://{BLOCKED}forum.com/04/a.php?id=B0B2D6E3584E49570050&cmd=img
- http://{BLOCKED}om/04/a.php?id=B0B2D6E3584E49570050&cmd=img
- http://{BLOCKED}rad-forum.com/04/a.php?id=B0B2D6E3584E49570050&cmd=img
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_RANSOM.ACG using either the Startup Disk or Recovery Console
[ Learn More ]
[ back ]
To identify and delete the malware/grayware file:
• On Windows XP and Server 2003 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Click Start>Run. In the Open input box, type secpol.msc and press Enter.
- In the left panel, double-click Local Policies>Security Options.
- In the right panel, double-click Recovery Console: Allow floppy copy and access to all drives and folders.
- Select Enabled and click OK.
- Insert the Windows Installation CD into the CD drive, then restart your computer.
- When prompted, press any key to boot from the CD.
- On the main menu, type r to go to the Recovery Console.
- Type the number that corresponds to the drive and directory that contains Windows (usually C:\WINDOWS) and press Enter.
- Type the Administrator password and press Enter.
- In the input box, type the following then press Enter:
SET AllowAllPaths = TRUE
del "{malware/grayware path and file name}" - Type exit and press Enter to restart the system normally.
• On Windows Vista and 7 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Insert your Windows Installation DVD in the DVD drive, then Press the restart button.
- When prompted, press any key to boot from the CD.
- Depending on your Windows Installation DVD, you might be required to select the installation language. Then on the Install Windows window, choose your language, locale, and keyboard layout or input method. Click Next, then click Repair your computer.
- Select Use recovery tools that can help fix problems starting Windows. Select your installation of Windows. Click Next.
- If the Startup Repair window appears, click Cancel, Yes, then Finish.
- In the System Recovery Options window, click Command Prompt.
- In the Command Prompt window, type the following then press Enter:
BootRec.exe /fixmbr
del "{malware/grayware path and file name}" - Type exit and press Enter to close the Command Prompt window.
- Click Restart to restart the system normally.
Step 3
To enable Registry Editor, Task Manager, and Folder options:
- Open Notepad. To do this:
- For Windows 2000, XP, and Server 2003 users:
Click Start > Run, type Notepad in the text box provided, then press Enter. - For Windows Vista and 7 users:
Click Start > type NotepadOn Error Resume Next
Set shl = WScript.CreateObject("WScript.Shell")
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableRegistryTools", "0", "REG_DWORD"
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableTaskMgr", "0", "REG_DWORD"
, then press Enter.
- Copy and paste the following script:
- Save this file asOn Error Resume Next
Set shl = WScript.CreateObject("WScript.Shell")
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableRegistryTools", "0", "REG_DWORD"
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableTaskMgr", "0", "REG_DWORD"
On Error Resume Next
Set shl = WScript.CreateObject("WScript.Shell")
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableRegistryTools", "0", "REG_DWORD"
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableTaskMgr", "0", "REG_DWORD"
C:RESTORE.VBS.
- Click Start>Run again, type C:RESTORE.VBS in the text box provided, then press Enter.
- Click Yes at theOn Error Resume Next
Set shl = WScript.CreateObject("WScript.Shell")
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableRegistryTools", "0", "REG_DWORD"
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableTaskMgr", "0", "REG_DWORD"
On Error Resume Next
Set shl = WScript.CreateObject("WScript.Shell")
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableRegistryTools", "0", "REG_DWORD"
shl.RegWrite "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableTaskMgr", "0", "REG_DWORD"
prompt of the message box to execute the .VBS file.
Step 4
Delete this registry key
[ Learn More ]
[ back ]
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
To delete the registry key this malware/grayware/spyware created:
- Restart your computer in Safe Mode. For instructions on how to do this, you may refer to this page. If the preceding step requires you to restart in safe mode, you may proceed to #2.
- Open Registry Editor. To do this, click Start>Run, type REGEDIT in the text box provided, then press Enter.
- In the left panel of the Registry Editor window, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Image File Execution Options - Still in the left panel, locate and delete the key:
{application name} - Close Registry Editor.
Step 5
Restore this modified registry value
[ Learn More ]
[ back ]
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 NT\CurrentVersion\Winlogon
- From: Userinit = "%System%\userinit.exe, %System%\{random}.exe,"
To: Userinit = "%System%\userinit.exe,"
To restore the registry value this malware/grayware modified:
- Open Registry Editor. Click Start>Run, type REGEDIT in the text box provided, and then press Enter.
- In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Winlogon - In the right panel, locate the registry value:
Userinit = "%System%\userinit.exe, %System%\{random}.exe," - Right-click on the value name and choose Modify. Change the value data of this entry to:
Userinit = "%System%\userinit.exe," - Close Registry Editor.
Step 6
Scan your computer with your Trend Micro product to delete files detected as TROJ_RANSOM.ACG. 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.
NOTES:
Restore Safe Boot Registry Settings
To restore safe boot registry settings:
- Open a text editor like Notepad.
- Copy and paste the following script:
- On Windows 2000:
- On Windows Server 2003:
- On Windows XP:
- On Windows Vista:
- On Windows 7:
- Save this file as RESTORE.REG.
- Execute the file RESTORE.REG.
Did this description help? Tell us how we did.