RANSOM_CONHOOD.A

August 10, 2017
 Analysis by: Marvelous Pelin
 ALIASES:

Ransom.RobinHood(Malwarebytes)

 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.

  TECHNICAL DETAILS

File Size:

1,771,008 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

02 Aug 2017

Payload:

Connects to URLs/IPs, Steals information, Displays graphics/image, 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 drops the following files:

  • %User Temp%\wallpaper1.bmp - set as desktop wallpaper
  • %Desktop%\ROBINHOOD-TIMER.exe
  • %User Temp%\Microsoft.Win32.TaskScheduler.dll
  • %User Temp%\luncher.exe
  • %User Temp%\updater.exe
  • %Desktop%\READ_IT.txt - ransom note
  • %User Temp%\delete.bat

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %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.)

Other System Modifications

This Ransomware adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRegistry

It adds the following registry entries:

HKEY_CURRENT_USER\Software\WinRegistry
Unknown = {yyyy/MM/dd hh:mm:ss}

It modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\wallpaper1.bmp

(Note: The default value data of the said registry entry is {user preference}.)

HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = 0

(Note: The default value data of the said registry entry is {user preference}.)

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = 1

(Note: The default value data of the said registry entry is {user preference}.)

It sets the system's desktop wallpaper to the following image:

Information Theft

This Ransomware gathers the following data:

  • Computer Name
  • Username

Other Details

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

  • https://syrian223.{BLOCKED}hostapp.com/security.php?info=

Ransomware Routine

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

  • .Robinhood
  • .dll
  • .TMP
  • .exe

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

  • Windows
  • AppData

It renames encrypted files using the following names:

  • {original filename and extension}.Robinhood

NOTES:

The ransom note contains the following:

It also displays the following when %Desktop%\ROBINHOOD-TIMER.exe is executed:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.570.08

FIRST VSAPI PATTERN DATE:

02 Aug 2017

VSAPI OPR PATTERN File:

13.571.00

VSAPI OPR PATTERN Date:

03 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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Software
    • WinRegistry

Step 5

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.
  • %User Temp%\delete.bat
  • %User Temp%\wallpaper1.bmp
  • %Desktop%\ROBINHOOD-TIMER.exe
  • %User Temp%\Microsoft.Win32.TaskScheduler.dll
  • %User Temp%\luncher.exe
  • %User Temp%\updater.exe
  • %Desktop%\READ_IT.txt

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_CONHOOD.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 7

Reset your Desktop properties

[ Learn More ]

Step 8

Restore encrypted files from backup.

Step 9

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


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