RANSOM_CRYSIS.L

 Analysis by: Christian Noel Olalia

 ALIASES:

Trojan-Ransom.Win32.Crusis.to (KASPERSKY); Trojan.Gen.2 (NORTON); Ransom:Win32/Wadhrama [non_writable_container] (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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:

126,464 bytes

Memory Resident:

Yes

Initial Samples Received Date:

01 Mar 2018

Payload:

Terminates processes, Encrypts files, Displays message/message boxes

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 ? (if admin)
  • %Application Data%\{Malware Filename}.exe ? (if non-admin)

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %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.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\syncronize_{random 6 characters}A
  • Global\syncronize_{random 6 characters}U

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
{Malware Filename}.exe = %System%\{Malware Filename}.exe

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

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %Application Data%\Microsoft\Windows\Start Menu\Programs\Startup\{Malware Filename}.exe
  • %ProgramData%\Microsoft\Windows\Start Menu\Programs\Startup\{Malware Filename}.exe

(Note: %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.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 entries:

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""

Process Termination

This Ransomware terminates the following services if found on the affected system:

  • FirebirdGuardianDefaultInstance
  • FirebirdServerDefaultInstance
  • sqlwriter
  • mssqlserver
  • sqlserveradhelper

It terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • 1c8.exe
  • 1cv77.exe
  • outlook.exe
  • postgres.exe
  • mysqld-nt.exe
  • mysqld.exe
  • sqlserver.exe

Other Details

This Ransomware does the following:

  • It deletes shadow copies by executing the following command:
    • vssadmin delete shadows /all /quiet
  • It executes the following commands:
    • mode con cp select=1251
  • It avoids encrypting files/directories with the following strings:
    • %Windows%
    • boot.ini
    • bootfont.bin
    • ntldr
    • ntdetect.com
    • Io.sys
    • Info.hta
    • FILES_ENCRYPTED.txt
    • {Malware Filename}.exe
  • It encrypts files in all fixed, remote and removable drives.

Ransomware Routine

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

  • .id-{ID}.[{BLOCKED}TC@{BLOCKED}k.li].java

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

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

(Note: %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.. %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:\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.. %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

NOTES:

This ransomware displays the following ransom notes after encrypting the target files:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.114.04

FIRST VSAPI PATTERN DATE:

07 Mar 2018

VSAPI OPR PATTERN File:

14.115.00

VSAPI OPR PATTERN Date:

08 Mar 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 Filename}.exe = %System%\{Malware Filename}.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {Malware Filename}.exe = %Application Data%\{Malware Filename}.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 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.
  • %Application Data%\Info.hta
  • %System%\Info.hta
  • %User Startup%\Info.hta
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\Info.hta
  • {Public User Desktop}\FILES ENCRYPTED.txt
  • {All Drives}\FILES ENCRYPTED.txt
  • %Desktop%\FILES ENCRYPTED.txt

Step 6

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