Ransom_WINLOCK.SM

 Analysis by: Henry Alarcon Jr.

 ALIASES:

Artemis!E89F7E559055 (McAfee), Trojan.Ransomlock (Symantec)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

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.

  TECHNICAL DETAILS

File Size:

211456 bytes

File Type:

EXE

File Compression:

UPX

Memory Resident:

Yes

Payload:

Locks screen, Terminates processes, Displays graphics/image

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.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware Filename} = {Malware File Path}\{Malware Filename}.exe

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\M\
Power
(Default) = Service

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\M\
ProfSvc
(Default) = Service

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\M\
WinDefend
(Default) = Service

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\N\
MPSDrv
(Default) = Service

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\N\
MPSSvc
(Default) = Service

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\N\
Power
(Default) = Service

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\N\
ProfSvc
(Default) = Service

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\N\
WinDefend
(Default) = Service

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

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

It deletes the following registry keys:

HKLM\SYSTEM\ControlSet001\
Control\SafeBoot\Minimal

HKLM\SYSTEM\ControlSet001\
Control\SafeBoot\Network

Process Termination

This Ransomware terminates the following processes if found running in the affected system's memory:

  • TaskMngr.exe
  • explorer.exe

Other Details

This Ransomware does the following:

  • Does not encrypt. Instead, it locks the screen and displays the following

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

12.682.05

FIRST VSAPI PATTERN DATE:

29 Jul 2016

VSAPI OPR PATTERN File:

12.683.00

VSAPI OPR PATTERN Date:

30 Jul 2016

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

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 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {Malware Filename} = {Malware File Path}\{Malware Filename}.exe

Step 5

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\SYSTEM\ControlSet001\Control\SafeBoot
    • N
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot
    • M

Step 6

Restore this modified 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = "1"

Step 7

Search and delete these files

[ Learn More ]
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.
  • {Malware File Path}\{Malware Filename}.exe

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom_WINLOCK.SM. 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.


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