Ransom.Win32.MAOLOA.NZU

 Modified by: John Anthony Banes

 ALIASES:

Ransom:Win32/Maoloa.KA (Microsoft)

 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size:

186,880 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

27 Aug 2019

Payload:

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 files:

  • {malware path}\ids.txt -> contains encryption key and available drives
  • %AppDataLocal%\.{Machine GUID}
  • {directory with encrypted files}\.{Machine GUID} -> contains encryption key, extension, ransom note file name

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

This Ransomware creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
WindowsUpdateCheck = "{malware path and filename}.exe"

Other System Modifications

This Ransomware modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\HomeGroup
DisableHomeGroup = "1"

(Note: The default value data of the said registry entry is {User Preference}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = "1"

(Note: The default value data of the said registry entry is {User Preference}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender\Real-Time Protection
DisableRealtimeMonitoring = "1"

(Note: The default value data of the said registry entry is {User Preference}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender\Real-Time Protection
DisableBehaviorMonitoring = "1"

(Note: The default value data of the said registry entry is {User Preference}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender\Real-Time Protection
DisableOnAccessProtection = "1"

(Note: The default value data of the said registry entry is {User Preference}.)

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Terminal Server Client\Default

HKEY_CURRENT_USER\Software\Microsoft\
Terminal Server Client\Servers

File Infection

This Ransomware avoids infecting files that contain the following strings in their names:

  • windows
  • bootmgr
  • pagefile.sys
  • boot
  • ids.txt
  • NTUSER.DAT
  • PerfLogs

Other Details

This Ransomware does the following:

  • It encrypts files in Remote, Fixed, Removable drives
  • It avoids encrypting files with the following extensions:
    • dll
    • ini
    • lnk
    • sys
  • It deletes shadow copies by executing the following commands:
    • vssadmin delete shadows /all /quiet
    • sc stop vss
    • sc config vss start=disabled
  • It disables the following services by executing the following commands:
    • sc config browser
    • sc config browser start=enabled
    • sc stop MongoDB
    • sc config MongoDB start=disabled
    • sc stop SQLWriter
    • sc config SQLWriter start=disabled
    • sc stop MSSQLServerOLAPService
    • sc config MSSQLServerOLAPService start=disabled
    • sc stop MSSQLSERVER
    • sc config MSSQLSERVER start=disabled
    • sc stop MSSQL$SQLEXPRESS
    • sc config MSSQL$SQLEXPRESS start=disabled
    • sc stop ReportServer
    • sc config ReportServer start=disabled
    • sc stop OracleServiceORCL
    • sc config OracleServiceORCL start=disabled
    • sc stop OracleDBConsoleorcl
    • sc config OracleDBConsoleorcl start=disabled
    • sc stop OracleMTSRecoveryService
    • sc config OracleMTSRecoveryService start=disabled
    • sc stop OracleVssWriterORCL
    • sc config OracleVssWriterORCL start=disabled
    • sc stop MySQL
    • sc config MySQL start=disabled
  • It clears event logs it enumerated by using the following:
    • wevtutil el -> enumerates event logs
    • wevtutil cl -> clears event logs

Ransomware Routine

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

  • .Hermes666

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

  • {directory with encrypted files}\HOW TO BACK YOUR FILES.txt

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.326.02

FIRST VSAPI PATTERN DATE:

27 Aug 2019

VSAPI OPR PATTERN File:

15.327.00

VSAPI OPR PATTERN Date:

28 Aug 2019

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

    • Troj.Win32.TRX.XXPE50FFF031

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 4

Identify and terminate files detected as Ransom.Win32.MAOLOA.NZU

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 5

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • WindowsUpdateCheck = "{malware path and filename}.exe"

Step 6

Restore this modified 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\Policies\Microsoft\Windows\HomeGroup
    • From: DisableHomeGroup = "1"
      To: DisableHomeGroup = {User Preference, "0" is preferred}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
    • From: DisableAntiSpyware = "1"
      To: DisableAntiSpyware = {User Preference, "0" is preferred}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection
    • From: DisableRealtimeMonitoring = "1"
      To: DisableRealtimeMonitoring = {User Preference, "0" is preferred}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection
    • From: DisableBehaviorMonitoring = "1"
      To: DisableBehaviorMonitoring = {User Preference, "0" is preferred}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection
    • From: DisableOnAccessProtection = "1"
      To: DisableOnAccessProtection = {User Preference, "0" is preferred}

Step 7

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.
  • {malware path}\ids.txt
  • {directory with encrypted files}\.{Machine GUID}
  • %AppDataLocal%\.{Machine GUID}
  • {directory with encrypted files}\HOW TO BACK YOUR FILES.txt

Step 8

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.MAOLOA.NZU. 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 9

Restore encrypted files from backup.


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