Ransom.MSIL.COBRALOCKER.AB
TR/Dropper.MSIL.Gen (ANTIVIR); Ransom:MSIL/CryptoLocker.DD!MTB (MICROSOFT)
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It encrypts files found in specific folders. It drops files as ransom note.
TECHNICAL DETAILS
Arrival Details
This Ransomware 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 Ransomware adds the following processes:
- "C:\Windows\System32\cmd.exe" /k takeown /f C:\bootmgr && icacls C:\bootmgr /grant %username%:F && del C:\bootmgr && takeown /f C:\Windows\System32\LogonUI.exe && icacls C:\Windows\System32\LogonUI.exe && del C:\Windows\System32\LogonUI.exe && exit
Other System Modifications
This Ransomware deletes the following files:
- %Desktop%\desktop.ini
- %User Profile%\Downloads\desktop.ini
- %User Profile%\Documents\desktop.ini
- %User Profile%\Pictures\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).)
Other Details
This Ransomware does the following:
- Hides the window of the following running processes:
- cmd
- regedit
- Processhacker
- sdclt
- powershell
- processhacker
- Processhacker2
- gpedit
- gpedit.msc
Ransomware Routine
This Ransomware encrypts files found in the following folders:
- %Desktop%
- %User Profile%\Downloads
- %User Profile%\Documents - not including its subdirectories
- %User Profile%\Pictures
(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 appends the following extension to the file name of the encrypted files:
- .locked
It drops the following file(s) as ransom note:
- %Desktop%\readme.txt
SOLUTION
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.XXPE50FFF040
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
Identify and terminate files detected as Ransom.MSIL.COBRALOCKER.AB
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 4
Scan your computer with your Trend Micro product to delete files detected as Ransom.MSIL.COBRALOCKER.AB. 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 5
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.
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