Ransom.Win32.NEMTY.WLDG

 Analysis by: Mc Justine De Guzman

 ALIASES:

Trojan-Ransom.Nemty (Ikarus) ;

 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:

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:

20,272 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

14 Jun 2020

Payload:

Displays message/message boxes, 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.

Installation

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

  • na mne prigaet zhopa, pamc, pamc, pamc, pamc, pamc, ya vse

Other Details

This Ransomware does the following:

  • After the encryption, it changes the desktop background to %User Temp%\GOOBA.jpg

(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Ransomware Routine

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

  • TELEGRAM-RECOVER.txt

It avoids encrypting files found in the following folders:

  • Windows
  • $Recycle bin
  • RSA
  • Ntuser.dat
  • Programdata
  • Appdata
  • Program Files
  • Program Files (x86)

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

  • .TELEGRAM

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

  • {Encrypted folder}\TELEGRAM-RECOVER.txt
  • %User Temp%\GOOBA.jpg

It avoids encrypting files with the following file extensions:

  • .exe
  • .log
  • .cab
  • .cmd
  • .com
  • .cpl
  • .ini
  • .dll
  • .url
  • .ttf
  • .mp3
  • .pif
  • .mp4
  • .TELEGRAM
  • .msi

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.932.02

FIRST VSAPI PATTERN DATE:

15 Jun 2020

VSAPI OPR PATTERN File:

15.933.00

VSAPI OPR PATTERN Date:

16 Jun 2020

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     
    • Troj.Win32.TRX.XXPE50FFF036

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

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 4

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.
  • {Encrypted folder}\TELEGRAM-RECOVER.txt
  • %User Temp%\GOOBA.jpg

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.NEMTY.WLDG. 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.


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