Analysis by: Martin Xavier Co
ALIASES:

Ransom:Win32/Spora.B (Microsoft); Trojan-Ransom.Win32.Spora.enu (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: 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 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: 24,576 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 25 Aug 2017
Payload: Connects to URLs/IPs, Displays graphics/image, 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 drops the following files:

  • %Application Data%\{mutex name}

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on 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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • sTlLoTpq

Other Details

This Ransomware connects to the following website to send and receive information:

  • {BLOCKED}rtlfan3j76.onion

It executes the following command to disable/stop/delete Windows components:

  • vssadmin.exe delete shadows /quiet /all

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .1cd
  • .7z
  • .accdb
  • .backup
  • .bak
  • .cd
  • .cdr
  • .dbf
  • .doc
  • .docx
  • .dwg
  • .jpeg
  • .jpg
  • .mdb
  • .odt
  • .pdf
  • .ppt
  • .pptx
  • .psd
  • .rar
  • .rtf
  • .sql
  • .sqlite
  • .tiff
  • .xls
  • .xlsx
  • .zip

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

  • windows
  • program files
  • program files (x86)
  • games
  • appdata

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

  • {folder of encrypted files}\README_{mutex name}.hta

NOTES:

This ransomware encrypts files, but does not rename and/or append any custom extension.

It also executes README_{mutex name}.hta, and will display the following:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.616.07
FIRST VSAPI PATTERN DATE: 25 Aug 2017
VSAPI OPR PATTERN File: 13.617.00
VSAPI OPR PATTERN Date: 26 Aug 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

Scan your computer with your Trend Micro product to delete files detected as RANSOM_SPORA.F117HP. 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 4

Search and delete this file

[ 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.  
  • %Application Data%\{mutex name}
  • {folder of encrypted files}\README_{mutex name}.hta

Step 5

Restore encrypted files from backup.


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