Analysis by: Noel Anthony Llimos
ALIASES:

W32/Crysis.L!tr.ransom (Fortinet)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: Yes

  • Encrypted: No

  • 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 is capable of encrypting files in the affected system.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 94,720 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 29 Aug 2018

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 File Name}.exe
  • %User Startup%\{Malware File Name}.exe
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\{Malware File Name}.exe
  • %Application Data%\{Malware File Name}.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.. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000, XP, and Server 2003, or C:\ProgramData on Windows Vista, 7, and 8. . %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.)

It leaves text files that serve as ransom notes containing the following:

  • all your data has been locked us
  • You want to return?
  • write email darkbtc8@cock.lu

Autostart Technique

This Ransomware modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{Malware File Name}.exe = %Application Data\{Malware File Name}.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware File Name}.exe = %Application Data\{Malware File Name}.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
%System%\Info.hta = mshta.exe "%System%\Info.hta"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
%Application Data%\Info.hta = mshta.exe "%Application Data%\Info.hta"

Other Details

This Ransomware is capable of encrypting files in the affected system.

Ransomware Routine

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

  • .id-{Generated Victim ID}.[darkbtc8@cock.lu].bip

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

  • {All Drives}\FILES ENCRYPTED.txt
  • {Public User Desktop}\FILES ENCRYPTED.txt
  • %Desktop%\FILES ENCRYPTED.txt
  • %Start Menu%\Programs\Startup\Info.hta
  • %ProgramData%\Microsoft\Windows\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.. %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.. %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in 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: 14.472.06
FIRST VSAPI PATTERN DATE: 29 Aug 2018
VSAPI OPR PATTERN File: 14.473.00
VSAPI OPR PATTERN Date: 30 Aug 2018

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 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 File Name}.exe = %Application Data\{Malware File Name}.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {Malware File Name}.exe = %Application Data\{Malware File Name}.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • %System%\Info.hta = mshta.exe "%System%\Info.hta"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • %Application Data%\Info.hta = mshta.exe "%Application Data%\Info.hta"

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.
  • %System%\{Malware File Name}.exe
  • %User Startup%\{Malware File Name}.exe
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\{Malware File Name}.exe
  • %Application Data%\{Malware File Name}.exe
  • {All Drives}\FILES ENCRYPTED.txt
  • {Public User Desktop}\FILES ENCRYPTED.txt
  • %Desktop%\FILES ENCRYPTED.txt
  • %Start Menu%\Programs\Startup\Info.hta
  • %ProgramData%\Microsoft\Windows\Start Menu\Programs\Startup\Info.hta
  • %System%\Info.hta
  • %Application Data%\Info.hta

Step 6

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

Restore encrypted files from backup.


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