Ransom.Win32.DCRY.B

 Analysis by: Robert Nicole Malagad

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware, Spammed via email

This Ransomware arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size:

2,891,776 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Jul 2017

Payload:

Displays message/message boxes, Modifies system registry

Arrival Details

This Ransomware arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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:

  • %User Temp%\{Malware File Name}.{Language code}
  • %Windows%\message.vbs
  • {Encrypted File Directory}\READ_ME_MY_FRIEND.txt

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Local\MSCTF.Asm.MutexDefault1

Other System Modifications

This Ransomware adds the following registry keys:

HKEY_CLASSES_ROOT\.qwqd\shell\
open\command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.qwqd\shell\open\
command\(Default)

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.qwqd\shell\open\
command
(Default) = wscript "%System Root%\Windows\message.vbs"

Other Details

This Ransomware does the following:

  • It deletes shadow copies by executing the following command:
      vssadmin delete shadows /all /quiet
  • It drops a ransom note with the following content:

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • .qwqd

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.598.03

FIRST VSAPI PATTERN DATE:

31 Oct 2018

VSAPI OPR PATTERN File:

14.599.00

VSAPI OPR PATTERN Date:

01 Nov 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

Identify and terminate files detected as Ransom.Win32.DCRY.B

[ Learn More ]
  1. 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.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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.
  • {Encrypted File Directory}\READ_ME_MY_FRIEND.txt
  • %User Temp%\{Malware File Name}.{Language code}
  • %Windows%\message.vbs

Step 6

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_LOCAL_MACHINE\SOFTWARE\Classes\.qwqd\shell\open\command
    • (Default) = wscript "%System Root%\\Windows\\message.vbs"

Step 7

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_CLASSES_ROOT\.qwqd\shell\open\command
    • {}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.qwqd\shell\open\command\(Default)
    • {}

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.DCRY.B. 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 9

Restore encrypted files from backup.


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