Analysis by: Maureen Reyes
ALIASES:

Ransom:Win32/Wadhrama.C (Microsoft), Trojan-Ransom.Win32.Crusis.to (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 drops files as ransom note.

  TECHNICAL DETAILS

File Size: 94,720 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 02 Feb 2019

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 copies of itself into the affected system:

  • %System%\{Malware Filename}.exe
  • %User Startup%\{Malware Filename}.exe
  • %Start Menu%\Programs\Startup\{Malware Filename}.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows XP, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista, 7, and 8.)

It adds the following processes:

  • /c mode con cp select=1251
  • /c vssadmin delete shadows /all /quiet

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • .[dr{BLOCKED}888@mail.fr].888

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

  • %Desktop%\FILES ENCRYPTED.txt
  • %Public%\Desktop\FILES ENCRYPTED.txt
  • {Drive Letter}:\FILES ENCRYPTED.txt
  • %User Startup%\Info.hta
  • %Start Menu%\Programs\Startup\Info.hta
  • %System%\Info.hta
  • %Application Data%\Info.hta

(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista, 7, and 8.. %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows XP, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista, 7, and 8.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.790.07
FIRST VSAPI PATTERN DATE: 03 Feb 2019
VSAPI OPR PATTERN File: 14.791.00
VSAPI OPR PATTERN Date: 04 Feb 2019

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

Delete this registry value

[ 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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • {Malware Filename}.exe = "%System%\{Malware Filename}.exe"

Step 4

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%\FILES ENCRYPTED.txt
  • %Public%\Desktop\FILES ENCRYPTED.txt
  • {Drive Letter}:\FILES ENCRYPTED.txt
  • %User Startup%\Info.hta
  • %Start Menu%\Programs\Startup\Info.hta
  • %System%\Info.hta
  • %Application Data%\Info.hta

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.CRYSIS.NDO. 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 the following Trend Micro Support pages for more information:

Step 6

Restore encrypted files from backup.

NOTES:
Enabling Volume Shadow Service 1. Run the command prompt (cmd.exe) as administrator. 2. Enable Volume Shadow Service by typing the following command: net start vss


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