Analysis by: Arvin Roi Macaraeg
ALIASES:

Trojan:Win32/Occamy.C (Microsoft), Trojan-Ransom.Win32.Encoder.be (Kaspersky), Win32/Filecoder.Crysis.U (ESET-NOD32)

 PLATFORM:

Windows

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

  • 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.

  TECHNICAL DETAILS

File Size: 4,668,416 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 13 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 Filename}.exe
  • %User Startup%\{Malware Filename}.exe
  • %Common 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.. %Common Startup% is the startup folder for all users, which is usually C:\Documents and Settings\All Users\Start Menu\Programs\Startup on Windows 2000, XP, and Server 2003, or C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It adds the following processes:

  • cmd.exe /c vssadmin delete shadows /all /quiet

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

  • {All Drives}:\FILES ENCRYPTED.txt
  • %Desktop%\FILES ENCRYPTED.txt
  • %Public%\Desktop\FILES ENCRYPTED.txt
  • %User Startup%\Info.hta
  • %Common Startup%\Info.hta
  • %Application Data%\Info.hta
  • %System%/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.. %Common Startup% is the startup folder for all users, which is usually C:\Documents and Settings\All Users\Start Menu\Programs\Startup on Windows 2000, XP, and Server 2003, or C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup 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.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
1.exe = "C:\Windows\System32\1.exe"

Ransomware Routine

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

  • .id-{ID}.[Fordecrypt72hours@{BLOCKED}q.com].bip

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.442.04
FIRST VSAPI PATTERN DATE: 14 Aug 2018
VSAPI OPR PATTERN File: 14.443.00
VSAPI OPR PATTERN Date: 15 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

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
    • 1.exe = "C:\Windows\System32\1.exe"

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYSIS.TICAOBI. 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 5

Restore encrypted files from backup.

NOTES:

  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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