Ransom.Win32.HERMES.THIBOAI

November 04, 2019
 Modified by: Jay Bradley Nebre
 ALIASES:

RDN/Generic.grp (McAfee); Trojan-Downloader.Win32.Dofoil.cfxn (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)

 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:

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 drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size:

245,248 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Nov 2019

Payload:

Displays message/message boxes, Encrpyts 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.

Dropping Routine

This Ransomware drops the following files:

  • %System Root%\Users\Public\PUBLIC
  • %System Root%\Users\Public\UNIQUE_ID_DO_NOT_REMOVE

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

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

  • WINDOWS
  • DECRYPT_INFORMATION.html
  • UNIQUE_ID_DO_NOT_REMOVE

It avoids encrypting files with the following strings in their file path:

  • Windows
  • AhnLab
  • Chrome
  • Mozilla
  • $Recycle.Bin

It renames encrypted files using the following names:

  • {Original Filename}[supportdecrypt@firemail.cc].HRM

It drops the following file(s) as ransom note:

  • DECRYPT_INFORMATION.html

It avoids encrypting files with the following file extensions:

  • dll
  • lnk
  • hrmlog
  • ini
  • exe

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.378.05

FIRST VSAPI PATTERN DATE:

20 Sep 2019

VSAPI OPR PATTERN File:

15.379.00

VSAPI OPR PATTERN Date:

21 Sep 2019

Step 1

Trend Micro products with the XGen technology detect this malware as

[ Learn More ]
Troj.Win32.TRX.XXPE50FFF031

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

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %System Root%\Users\Public\PUBLIC
  • %System Root%\Users\Public\UNIQUE_ID_DO_NOT_REMOVE

Step 4

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.HERMES.THIBOAI. 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 5

Restore encrypted files from backup.


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