Arrival Details
This Ransomware may be dropped by the following malware:
Installation
This Ransomware drops the following files:
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It adds the following processes:
- "C:\Windows\System32\cmd.exe" /takeown /f C:\Windows\System32\Taskmgr.exe && icacls C:\Windows\System32\Taskmgr.exe /grant %username%:F && del C:\Windows\System32\Taskmgr.exe && takeown /f C:\Windows\System32\LogonUI.exe && icacls C:\Windows\System32\LogonUI.exe /grant %username%:F && del C:\Windows\System32\LogonUI.exe && exit
- "C:\Windows\System32\shutdown.exe" /r /f /t 0
Other System Modifications
This Ransomware deletes the following files:
- %Desktop%\desktop.ini
- %User Profile%\Downloads\desktop.ini
- %User Profile%\Pictures\desktop.ini
- %User Profile%\Documents\desktop.ini
(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %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 adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = 1
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = 1
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\Current Version\Winlogon
Shell = empty
Process Termination
This Ransomware terminates the following processes if found running in the affected system's memory:
- cmd
- regedit
- Processhacker
- sdclt
- powershell
Other Details
This Ransomware adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
It does the following:
- The sample will delete the legitimate %System%\LogonUI.exe which will then be replaced by moving a dropped file %System Root%\LogonUI.exe to %System% which is responsible for displaying the following message on the screen:
Upon clicking "Contact Us", it will display the following message:
- It encrypts files found in the following directories:
- %Desktop%
- %User Profile%\Downloads
- %User Profile%\Pictures
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
- Troj.Win32.TRX.XXPE50FFF039
Step 2
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 3
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 4
Enable Registry Editor, Task Manager, and Folder options
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By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.
To enable Registry Editor, Task Manager, and Folder options:
- Open Notepad. To do this:
- For Windows 7 and Server 2008 (R2) users:
Click start. Type Notepad, then press Enter. - For Windows 8, 8.1, 10, and Server 2012 (R2) users:
Right-click on the lower-left corner of the screen. Click Run. Type Notepad in the input field, then press Enter.
- Copy and paste the following script:
- Save this file as C:\RESTORE.VBS.
- Run C:\RESTORE.VBS by double-clicking on the file.
- Click Yes at the prompt of the message box to execute the .VBS file.
Screen reader support enabled.
To enable Registry Editor, Task Manager, and Folder options:
- Open Notepad. To do this:
- For Windows 7 and Server 2008 (R2) users:
Click start. Type Notepad, then press Enter. - For Windows 8, 8.1, 10, and Server 2012 (R2) users:
Right-click on the lower-left corner of the screen. Click Run. Type Notepad in the input field, then press Enter.
- Copy and paste the following script:
- Save this file as C:\RESTORE.VBS.
- Run C:\RESTORE.VBS by double-clicking on the file.
- Click Yes at the prompt of the message box to execute the .VBS file.
Step 5
Delete this registry key
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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.
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
To delete registry keys this malware/grayware created:
- Open Registry Editor. To do this:
» For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter. - HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
- Close Registry Editor.
Step 6
Restore this modified registry value
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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\Current Version\Winlogon
- From: Shell = empty
To:
Shell = {Default Value}
To restore the registry value this malware/grayware modified:
- Open Registry Editor.
» For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click 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>Current Version>Winlogon - In the right panel, locate the registry value:
Shell = empty - Right-click on the value name and choose Modify. Change the value data of this entry to:
Shell = {Default Value} - Close Registry Editor.
Step 7
Search and delete this file
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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.
- %System%\LogonUI.exe (Please make sure that the filesize is equal to 12,800 bytes or 12.5KB)
To manually delete a malware/grayware file from an affected system:
•For Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):
- Open a Windows Explorer window.
- For Windows 7 and Server 2008 (R2) users, click Start>Computer.
- For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower-left corner of the screen,then click File Explorer.
- In the Search Computer/This PC input box, type:
- %System%\LogonUI.exe (Please make sure that the filesize is equal to 12,800 bytes or 12.5KB)
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7 and Windows Server 2008 (R2).
Step 8
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %Desktop%\desktop.ini
- %User Profile%\Downloads\desktop.ini
- %User Profile%\Pictures\desktop.ini
- %User Profile%\Documents\desktop.ini
Step 9
Scan your computer with your Trend Micro product to delete files detected as Ransom.MSIL.COBRALOCKER.AA. 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 the following Trend Micro Support pages for more information:
Step 10
Restore encrypted files from backup.
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