Ransom.Win32.MRDEC.MRA
Trojan-Ransom.FileCrypter (Ikarus);
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
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 drops files as ransom note.
TECHNICAL DETAILS
12,288 bytes
EXE
No
19 Dec 2019
Drops files
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 drops the following files:
- %Windows%\ncler.txt -> contains logging of the malware's activities
- %Windows%\clerlog.bat -> used to clear logs using wevtutil, delete contents in Recycle Bin, delete shadow copies of ncler.txt
- %System Root%\Decoding help.hta -> ransom note
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
It drops the following copies of itself into the affected system:
- %Windows%\searchfiles.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
Autostart Technique
This Ransomware adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
unlock = "%System Root%\Decoding help.hta"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
searchfiles = "%Windows%\searchfiles.exe"
Other System Modifications
This Ransomware adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.[ID]{Random Characters}[ID]
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\DateTime
orsa = "{Hex values}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\DateTime
rsa = "{Hex values}"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.[ID]{Random Characters}[ID]\shell\open\
command
(Default) = "%System%\mshta.exe %System Root%\Decoding help.hta"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
PromptOnSecureDesktop = "0"
(Note: The default value data of the said registry entry is {User Preference}.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"
(Note: The default value data of the said registry entry is {User Preference}.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorAdmin = "0"
(Note: The default value data of the said registry entry is {User Preference}.)
Process Termination
This Ransomware terminates the following processes if found running in the affected system's memory:
- All processes excluding the following:
- [System Process]
- System
- smss.exe
- dllhost.exe
- svchost.exe
- csrss.exe
- Microsoft.ActiveDirectory
- WebServices.exe
- cmd.exe
- mstsc.exe
- find.exe
- conhost.exe
- explorer.exe
- ctfmon.exe
- lsass.exe
- services.exe
- tasklist.exe
- winlogon.exe
- wmiprvse.exe
- msdts.exe
- bfsvc.exe
- AdapterTroubleshooter.exe
- alg.exe
- dwm.exe
- issch.exe
- rundll32.exe
- spoolsv.exe
- wininit.exe
- wmiprvse.exe
- wudfhost.exe
- taskmgr.exe
- rdpclip.exe
- logonui.exe
- lsm.exe
- searchui.exe
- searchindexer.exe
- processhacker.exe
- getpassvord_x64.exe
- 64.exe
- 32.exe
- mshta.exe
- fontdrvhost.exe
- sihost.exe
- pscan24.exe
- advanced_port_scanner.exe
- advanced_port_scanner_console.exe
- pscan24.tmp
- PSEXESVC.exe
- diskshadow.exe
- dfssvc.exe
Other Details
This Ransomware displays the following images:
It does the following:
- It encrypts files found in all drives including network drives
- It deletes all shadow copies using the following command:
- cmd /c vssadmin delete shadows /all
Ransomware Routine
This Ransomware avoids encrypting files with the following strings in their file name:
- Decoding help.hta
It avoids encrypting files found in the following folders:
- Windows
It appends the following extension to the file name of the encrypted files:
- .[ID]{Random Characters}[ID]
It drops the following file(s) as ransom note:
- {Encrypted directory}\Decoding help.hta
SOLUTION
9.850
15.568.05
19 Dec 2019
15.569.00
20 Dec 2019
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.XXPE50FFF033
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
Restart in Safe Mode
Step 5
Delete this registry value
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
- unlock = "%System Root%\Decoding help.hta"
- unlock = "%System Root%\Decoding help.hta"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- searchfiles = "%Windows%\searchfiles.exe"
- searchfiles = "%Windows%\searchfiles.exe"
Step 6
Delete this registry key
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_LOCAL_MACHINE\SOFTWARE\Classes\.[ID]{Random Characters}[ID]
Step 7
Restore this modified registry value
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\System
- PromptOnSecureDesktop = "0"
- PromptOnSecureDesktop = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- EnableLUA = "0"
- EnableLUA = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- ConsentPromptBehaviorAdmin = "0"
- ConsentPromptBehaviorAdmin = "0"
Step 8
Search and delete this file
- %Windows%\ncler.txt
- %Windows%\clerlog.bat
- %System Root%\Decoding help.hta
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.MRDEC.MRA. 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 10
Restore encrypted files from backup.
Step 11
Enabling Volume Shadow Service
- Run the command prompt (cmd.exe) as administrator.
- Enable Volume Shadow Service by typing the following command:
net start vss
Did this description help? Tell us how we did.