Analysis by: Christian Noel Olalia
ALIASES:

Trojan-Ransom.Win32.Gen.hfj (KASPERSKY); Downloader (NORTON); Troj/Ransom-EVN (SOPHOS_LITE)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

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.

  TECHNICAL DETAILS

File Size: 269,824 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 02 Feb 2018
Payload: Terminates processes, Encrypts 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.

Process Termination

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

  • calc.exe

Dropping Routine

This Ransomware drops the following files:

  • {Encrypted File Path}\note.txt - contains encryption key

Other Details

This Ransomware does the following:

  • Executes the following command:
    • cmd.exe / c vssadmin delete shadows / all / quiet & wmic shadowcopy delete & bcdedit / set{ default } bootstatuspolicy ignoreallfailures & bcdedit / set{ default } recoveryenabled no & wbadmin delete catalog - quiet

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • C:\test2\
  • {Drive Letter}:\

It appends the following extension to the file name of the encrypted files:

  • .[emaiemail@{BLOCKED}l.com].deuscrypt

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.942.05
FIRST VSAPI PATTERN DATE: 02 Feb 2018
VSAPI OPR PATTERN File: 13.943.00
VSAPI OPR PATTERN Date: 03 Feb 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

Identify and terminate files detected as RANSOM_DEUSCRYPT.THBOBH

[ 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 4

Remove the malware/grayware file dropped/downloaded by RANSOM_DEUSCRYPT.THBOBH. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • {Encrypted File Path}\note.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_DEUSCRYPT.THBOBH. 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 6

Restore encrypted files from backup.

NOTES:

  1. Enable services that are disabled using the command prompt.
  2. Run cmd.exe as administrator.
  3. To enable Windows Error Recovery Screen on Startup, use the following command:

    bcdedit /set {default} bootstatuspolicy displayallfailures

  4. To enable Startup Repair, use the following command:

    /bcedit /set {default} recoveryenabled Yes


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