Analysis by: Noel Anthony Llimos
 ALIASES:

HEUR:Trojan-Ransom.Win32.Generic (Kaspersky), Ransom:Win32/Genasom (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Canal de infecção: 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 with specific file extensions. It encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

Tipo de compactação: 18,944 bytes
Tipo de arquivo: EXE
Residente na memória: No
Data de recebimento das amostras iniciais: 18 Apr 2018
Carga útil: 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.

Other Details

This Ransomware does the following:

  • It deletes shadow copies by executing the following command:
    • cmd.exe /C vssadmin delete shadows /all /quiet
  • It displays the following upon successful encryption:

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .txt
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .jpg
  • .png
  • .csv
  • .sql
  • .mdb
  • .sln
  • .php
  • .asp
  • .aspx
  • .html
  • .xml
  • .psd
  • .rar
  • .zip
  • .mp3
  • .exe
  • .PDF
  • .rtf
  • .DT
  • .CF
  • .CFU
  • .mxl
  • .epf
  • .erf
  • .vrp
  • .grs
  • .geo
  • .elf
  • .lgf
  • .lgp
  • .log
  • .st
  • .pff
  • .mft
  • .efd
  • .ini
  • .CFL
  • .cer
  • .backup
  • .7zip
  • .tiff
  • .jpeg
  • .accdb
  • .sqlite
  • .dbf
  • 1cd
  • .mdb
  • .cd
  • .cdr
  • .dwg
  • .png

It encrypts files found in the following folders:

  • %User Profile%
  • %Desktop%
  • %ProgramData%
  • Removable Drives

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

  • .Satyr

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

  • {Encrypted Directory}\READ ME.txt

  SOLUTION

Mecanismo de varredura mínima: 9.850
Primeiro arquivo padrão VSAPI: 14.198.08
Data do lançamento do primeiro padrão VSAPI: 18 Apr 2018
VSAPI OPR Pattern Version: 14.199.00
VSAPI OPR Pattern veröffentlicht am: 19 Apr 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_SATYR.THDAHAH

[ 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

Scan your computer with your Trend Micro product to delete files detected as RANSOM_SATYR.THDAHAH. 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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