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Ransom.Win32.MILICRY.GRC

July 11, 2019
 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE 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.

  TECHNICAL DETAILS

File Size:

462,848 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Jul 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 adds the following processes:

  • %System%\svchost.exe -k netsvcs

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

Autostart Technique

This Ransomware registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WmiApRpl\Performance
PerfIniFile = "WmiApRpl.ini"

Other System Modifications

This Ransomware modifies the following file(s):

  • %System%\PerfStringBackup.INI

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

It deletes the following files:

  • %Program Files%\Google\Update\Install\{904D5A14-65BD-4383-8977-5F3A9E043C0D}\74.0.3729.169_chrome_installer.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It deletes the following folders:

  • %Program Files%\Google\Update\Install\{904D5A14-65BD-4383-8977-5F3A9E043C0D}

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WmiApRpl\Performance
Last Counter = "8262"

(Note: The default value data of the said registry entry is c14.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WmiApRpl\Performance
Last Help = "8263"

(Note: The default value data of the said registry entry is c15.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WmiApRpl\Performance
First Counter = "8096"

(Note: The default value data of the said registry entry is c08.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WmiApRpl\Performance
First Help = "8097"

(Note: The default value data of the said registry entry is c09.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WmiApRpl\Performance
Object List = "8096 8102 8112 8122 8142 8186 8196 8234 8240 8256"

(Note: The default value data of the said registry entry is 3080 3086.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\BITS
Type = "16"

(Note: The default value data of the said registry entry is 20.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WmiApRpl\Performance\
First Counter

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WmiApRpl\Performance\
First Help

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WmiApRpl\Performance\
Last Counter

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WmiApRpl\Performance\
Last Help

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WmiApRpl\Performance\
Disable Performance Counters

Dropping Routine

This Ransomware drops the following files:

  • %Windows%\inf\WmiApRpl\WmiApRpl.h
  • %System%\PerfStringBackup.TMP
  • %Windows%\inf\WmiApRpl\0009\WmiApRpl.ini

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

Other Details

This Ransomware connects to the following possibly malicious URL:

  • http://crl3.{BLOCKED}rt.com/EVCodeSigningSHA2-g1.crl
  • http://crl4.{BLOCKED}rt.com/EVCodeSigningSHA2-g1.crl

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

Step 1

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 2

Identify and terminate files detected as Ransom.Win32.MILICRY.GRC

[ 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 3

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\WmiApRpl\Performance
    • From: Last Counter = "8262"
      To: Last Counter = ""c14""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\WmiApRpl\Performance
    • From: Last Help = "8263"
      To: Last Help = ""c15""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\WmiApRpl\Performance
    • From: First Counter = "8096"
      To: First Counter = ""c08""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\WmiApRpl\Performance
    • From: First Help = "8097"
      To: First Help = ""c09""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\WmiApRpl\Performance
    • From: Object List = "8096 8102 8112 8122 8142 8186 8196 8234 8240 8256"
      To: Object List = ""3080 3086""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\BITS
    • From: Type = "16"
      To: Type = ""20""

Step 4

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %Windows%\inf\WmiApRpl\WmiApRpl.h
  • %System%\PerfStringBackup.TMP
  • %Windows%\inf\WmiApRpl\0009\WmiApRpl.ini

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.MILICRY.GRC. 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.

Step 7

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %System%\PerfStringBackup.INI

Step 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Program Files%\Google\Update\Install\{904D5A14-65BD-4383-8977-5F3A9E043C0D}\74.0.3729.169_chrome_installer.exe

Step 9

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WmiApRpl\Performance
    • First Counter
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WmiApRpl\Performance
    • First Help
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WmiApRpl\Performance
    • Last Counter
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WmiApRpl\Performance
    • Last Help
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WmiApRpl\Performance
    • Disable Performance Counters


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