Ransom.Win32.MIMIC.A

February 23, 2023

Analysis by: Kim Benedict Victorio

ALIASES:

UDS:Trojan-Ransom.Win32.Mimic.q (KASPERSKY)

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 deletes registry entries, causing some applications and programs to not function properly.

It encrypts files with specific file extensions. It drops files as ransom note. It avoids encrypting files with the following file extensions.

TECHNICAL DETAILS

File Size:

2,909,429 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Feb 2023

Payload:

Terminates processes, Drops files, Deletes 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:

%User Temp%\7ZipSfx.000\7za.exe
%User Temp%\7ZipSfx.000\Everything.exe
%User Temp%\7ZipSfx.000\Everything32.dll
%User Temp%\7ZipSfx.000\Everything64.dll
%User Temp%\7ZipSfx.000\Everything.ini
%User Temp%\7ZipSfx.000\Everything2.ini
%User Temp%\7ZipSfx.000\Horsesperm.exe
%User Temp%\7ZipSfx.000\sdel.exe
%User Temp%\7ZipSfx.000\sdel64.exe
%User Temp%\7ZipSfx.000\session.tmp
%User Temp%\7ZipSfx.000\Defender.exe
%AppDataLocal%\{GUID}\7za.exe → Copy file
%AppDataLocal%\{GUID}\Everything.exe → Copy file
%AppDataLocal%\{GUID}\Everything32.dll → Copy file
%AppDataLocal%\{GUID}\Everything64.dll → Copy file
%AppDataLocal%\{GUID}\Everything.ini → Copy file
%AppDataLocal%\{GUID}\Everything2.ini → Copy file
%AppDataLocal%\{GUID}\Horsesperm.exe → Copy file
%AppDataLocal%\{GUID}\sdel.exe → Copy file
%AppDataLocal%\{GUID}\sdel64.exe → Copy file
%AppDataLocal%\{GUID}\session.tmp → Copy file
%AppDataLocal%\{GUID}\Defender.exe → Copy file
{All affected directories}\Bigspermhorseballs_Decryption.txt
%UserTemp%\session.tmp
%UserTemp%\{Random Letters}.{Random Letters}.ps1 → It Deletes after
%UserTemp%\{Random Letters}.{Random Letters}.psm1 → It Deletes after

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

It adds the following processes:

"%UserTemp%\7ZipSfx.000\7za.exe" x -y -p23980242011156913804 Everything64.dll
"%UserTemp%\7ZipSfx.000\7za.exe" i
cmd.exe /c DC.exe /D
"%AppDataLocal%\{GUID}Defender.exe"
"%AppDataLocal%\{GUID}Defender.exe" -e watch -pid {PID of Defender.exe} -!
"%AppDataLocal%\{GUID}Defender.exe" -e ul1
"%AppDataLocal%\{GUID}Defender.exe" -e ul2
"%Program Files%\Everything\Everything.exe" -startup
powercfg.exe -H off
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 1} {GUID Group} {GUID Setting 1} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 1} {GUID Group} {GUID Setting 2} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 1} {GUID Group} {GUID Setting 3} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 1} {GUID Group} {GUID Setting 1} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 1} {GUID Group} {GUID Setting 2} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 1} {GUID Group} {GUID Setting 3} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 2} {GUID Group} {GUID Setting 1} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 2} {GUID Group} {GUID Setting 2} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 2} {GUID Group} {GUID Setting 3} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 2} {GUID Group} {GUID Setting 1} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 2} {GUID Group} {GUID Setting 2} 0"
"powercfg.exe -SETACVALUEINDEX {Power scheme GUID 2} {GUID Group} {GUID Setting 3} 0"
"powercfg.exe -S {Power scheme GUID 1}"
"powercfg.exe -S {Power scheme GUID 2}"
"powershell.exe -ExecutionPolicy Bypass ""Get-VM | Stop-VM"""
"powershell.exe -ExecutionPolicy Bypass ""Get-VM | Select-Object vmid | Get-VHD | %{Get-DiskImage -ImagePath $_.Path; Get-DiskImage -ImagePath $_.ParentPath} | Dismount-DiskImage"""
"powershell.exe -ExecutionPolicy Bypass ""Get-Volume | Get-DiskImage | Dismount-DiskImage"""

(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).. %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 creates the following folders:

%AppDataLocal%\{GUID}
%System Root%\temp

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

oooiheWoeohohLeooho

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
Defender = %AppDataLocal%\{GUID}\Defender.exe

Other System Modifications

This Ransomware modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\VSS
Start = 4