Analysis by: Wilbert Vidal

ALIASES:

Virus:Win32/Neshta.A (Microsoft); Virus.Win32.Neshta.a (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 is capable of encrypting files in the affected system.

It encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 262,656 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 22 Aug 2017
Payload: 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 component file(s):

  • %User Temp%\786B.tmp\Read@My.vbs - Voice Note that will be deleted after execution

(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.)

It drops and executes the following files:

  • %User Profile%\AppData\Local\temppicc.exe - Changes the Desktop Wallpaper
  • %User Profile%\AppData\Local\tempspesh.exe - Triggers the Ransom Voice Msg Note

(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.)

Other System Modifications

This Ransomware sets the system's desktop wallpaper to the following image:

Other Details

This Ransomware encrypts files with the following extensions:

  • .txt
  • .doc
  • .docx
  • .mp3
  • .xls
  • .xlsx
  • .ppt
  • .sql
  • .wmv
  • .mp4
  • .mp3
  • .iso
  • .dll
  • .jar
  • .pptx
  • .odt
  • .jpg
  • .tar
  • .gz
  • .bmp
  • .pbm
  • .rtf
  • .png
  • .csv
  • .sql
  • .mdb
  • .sln
  • .php\"
  • .avi
  • .mov
  • .flv
  • .amv
  • .mpv
  • .mtv
  • .asp
  • .aspx
  • .html
  • .xml
  • .psd
  • .pdf
  • .exe
  • .rv
  • .rvx
  • .ved
  • .wm
  • .wmv
  • .TXT
  • .JPG
  • .rar
  • .xwmv
  • .wma
  • .midi
  • .fla
  • .pdf
  • .wma
  • .ico
  • .gif
  • .GIF
  • .ogg
  • .mpg
  • .icns
  • .RAR
  • .png
  • .zip
  • .BAT
  • .Exe
  • .c
  • .exe
  • .PNG
  • .iso
  • .7z
  • .7Z

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • %Favorites%
  • %User Startup%
  • %Program Files%
  • %Application Data%
  • %User Profile%\Documents
  • %User Profile%\Pictures
  • %User Profile%\Desktop
  • %User Profile%\Music
  • %Application Data%\Microsoft\Windows\Start Menu\Programs

(Note: %Favorites% is the Favorites folder, where it usually is C:\Documents and Settings\{user name}\Favorites on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Favorites 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.. %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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %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.. %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.)

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

  • .Isis

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

  • %%Application Data%%\img.jpg - Wallpaper Ransom Note
  • %Desktop%\@-Decrypt-@.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.)

NOTES:

This ransomware displays the following as ransom note:

The following is the dropped text file:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.610.08
FIRST VSAPI PATTERN DATE: 22 Aug 2017
VSAPI OPR PATTERN File: 13.611.00
VSAPI OPR PATTERN Date: 23 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

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 Profile%\AppData\Local\tempspesh.exe
  • %User Profile%\AppData\Local\temppicc.exe
  • %%Application Data%%\img.jpg
  • %Desktop%\@-Decrypt-@.txt

Step 4

Reset your Desktop properties

[ Learn More ]

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_DZSPLITTER.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 6

Restore encrypted files from backup.


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