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RANSOM_WCRY.TIAOBFP

June 26, 2018
 Analysis by: Augusto II Remillano
 ALIASES:

Trojan.Ransom.WannaCryptor.H (BitDefender), Ransom:Win32/WannaCrypt.A!rsm (Microsoft), Ransom.Wannacry (Norton)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

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:

3,723,264 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Oct 2017

Payload:

Drops files, Connects to URLs/IPs

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%\tasksche.exe
  • %Windows%\qeriuwjhrf

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It adds the following processes:

  • {Malware filepath}\{Malware filename} -m security
  • %Windows%\tasksche.exe /i

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Autostart Technique

This Ransomware registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.0
ImagePath = "{Malware filepath}\{Malware filename} -m security"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.0
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.0
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.0
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.0
DisplayName = "Microsoft Security Center (2.0) Service"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.0
ObjectName = "LocalSystem"

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.0

Other Details

This Ransomware connects to the following possibly malicious URL:

  • http://www.{BLOCKED}sodp9ifjaposdfjhgosurijfaewrwergwea.com

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.342.02

FIRST VSAPI PATTERN DATE:

26 Jun 2018

VSAPI OPR PATTERN File:

14.343.00

VSAPI OPR PATTERN Date:

27 Jun 2018

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 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. 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\SYSTEM\CurrentControlSet\services
    • mssecsvc2.0

Step 5

Search and delete this file

[ 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.
  • %Windows%\tasksche.exe
  • %Windows%\qeriuwjhrf

Step 6

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