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RANSOM_SPORA.THEAH

May 29, 2017
 Analysis by: Ryan Paolo Maglaque
 ALIASES:

Trojan-Ransom.Win32.Spora.dpf(Kaspersky);Ransom.Spora(Norton);Ransom-Spora.b(NAI)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • 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 modifies Internet Explorer security settings. This puts the affected computer at greater risk, as it allows malicious URLs to be accessed by the computer.

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

  TECHNICAL DETAILS

File Size:

184,320 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

17 May 2017

Payload:

Connects to URLs/IPs, Drops files, 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%\Xkj1VYCu

(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:

  • Xkj1VYCu

Web Browser Home Page and Search Page Modification

This Ransomware modifies Internet Explorer zone settings.

Other Details

This Ransomware does the following:

  • Execute the following command:
    • vssadmin.exe delete shadows /quiet /all
  • Display the following ransom note(from the url {BLOCKED}.{BLOCKED}.19.190 ):

Ransomware Routine

This Ransomware encrypts files with the following extensions:

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

It avoids encrypting files found in the following folders:

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

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

  • {Encrypted File Directory}\HELP_Xkj1VYCu.html
  • %User Startup%\HELP_Xkj1VYCu.html

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.416.01

FIRST VSAPI PATTERN DATE:

18 May 2017

VSAPI OPR PATTERN File:

13.417.00

VSAPI OPR PATTERN Date:

19 May 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 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%\Xkj1VYCu
  • {Encrypted File Directory}\HELP_Xkj1VYCu.html
  • %User Startup%\HELP_Xkj1VYCu.html

Step 4

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

Reset Internet security settings

[ Learn More ]

Step 6

Restore encrypted files from backup.


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