Analysis by: Byron Jon Gelera
ALIASES:

Ransom:Win32/Spectrypt.A (Microsoft); Trojan-Ransom.Win32.Purgen.eg (Kaspersky)

 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, Dropped by other malware

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 connects to certain websites to send and receive information.

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 191,488 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 09 Jun 2017
Payload: 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 connects to the following website to send and receive information:

  • http://{BLOCKED}03.{BLOCKED}h.ru/testing.php?mode={value}

It does the following:

  • This ransomware deletes shadow copies by executing the following commands:
    • vssadmin.exe delete shadows /all /quiet
    • WMIC.exe shadowcopy delete

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .txt
  • .doc
  • .docx
  • .pdf
  • .rtf
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .bmp
  • .jpg
  • .jpeg
  • .gif
  • .tiff
  • .png
  • .mp3
  • .wav
  • .mp4
  • .mpeg
  • .avi
  • .zip
  • .rar
  • .wmv

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

  • Windows
  • $Recycle.Bin
  • Microsoft
  • Mozilla Firefox
  • Opera
  • Internet Explorer
  • Temp
  • Local
  • LocalLow
  • Program Files
  • Program Files (x86)
  • Chrome

It renames encrypted files using the following names:

  • {Random Characters}.spectre

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

  • %Desktop%\HowToDecryptIMPORTANT!.txt
  • {Path of Encrypted File}\HowToDecryptIMPORTANT!.txt

(Note: %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.)

It leaves text files that serve as ransom notes containing the following text:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.460.08
FIRST VSAPI PATTERN DATE: 09 Jun 2017
VSAPI OPR PATTERN File: 13.461.00
VSAPI OPR PATTERN Date: 10 Jun 2017

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

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.  
  • %Desktop%\HowToDecryptIMPORTANT!.txt
  • {Path of Encrypted File}\HowToDecryptIMPORTANT!.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_SPECTRE.A. 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 5

Restore encrypted files from backup.


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