BlackCat (ALPHV) Ransomware: Insider Affiliate Detection and Defense Guide

---
title: Potential BlackCat (ALPHV) Ransomware Execution Pattern
id: 8a4b2c1d-9e6f-4a3b-8c5d-1e2f3a4b5c6d
status: experimental
description: Detects suspicious command-line arguments often used by the Rust-based BlackCat/ALPHV ransomware binary, specifically the use of '--path' or '-p' for targeting and '--public-key' for encryption setup.
references:
  - https://attack.mitre.org/techniques/T1486/
author: Security Arsenal
date: 2024/10/22
tags:
  - attack.impact
  - attack.t1486
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '.exe'
    CommandLine|contains:
      - '--public-key'
      - '--path'
      - '-p '
  condition: selection
falsepositives:
  - Legitimate administrative tools using similar flags (rare for this combination)
level: critical
---
title: Data Exfiltration via Rclone (BlackCat TTP)
id: 9b5c3d2e-0f7a-5b4c-9d6e-2f3a4b5c6d7e
status: experimental
description: Detects the execution of rclone.exe, a tool frequently used by BlackCat affiliates to exfiltrate sensitive data to cloud storage services prior to encryption.
references:
  - https://attack.mitre.org/techniques/T1567/
author: Security Arsenal
date: 2024/10/22
tags:
  - attack.exfiltration
  - attack.t1567.002
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\rclone.exe'
    CommandLine|contains:
      - 'sync'
      - 'copy'
      - 'mega'
      - 'pcloud'
falsepositives:
  - Authorized use of rclone by IT administrators for backup or data migration
level: high
---
title: Volume Shadow Copy Deletion via Vssadmin
id: 1c6d4e3f-1g8b-6c5d-0e7f-3g4a5b6c7d8e
status: experimental
description: Detects attempts to delete Volume Shadow Copies using vssadmin, a common precursor to ransomware encryption to prevent file recovery.
references:
  - https://attack.mitre.org/techniques/T1490/
author: Security Arsenal
date: 2024/10/22
tags:
  - attack.impact
  - attack.t1490
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\vssadmin.exe'
    CommandLine|contains:
      - 'delete shadows'
      - 'resize shadowstorage'
falsepositives:
  - System administration tasks legitimately managing shadow storage
level: high

// Hunt for BlackCat Ransomware Indicators and Exfil Tools
// Looks for Rclone usage, Vssadmin deletion, and unusual Rust executables
let ExfilTools = DeviceProcessEvents
| where Timestamp > ago(7d)
| where FileName in~ ("rclone.exe", "winscp.exe", "filezilla.exe") 
   or ProcessCommandLine has_any ("mega", "pcloud", "sync", "copy");
let AntiForensics = DeviceProcessEvents
| where Timestamp > ago(7d)
| where FileName =~ "vssadmin.exe" 
   and ProcessCommandLine has_any ("delete shadows", "resize shadowstorage");
let SuspiciousRust = DeviceProcessEvents
| where Timestamp > ago(7d)
| where ProcessCommandLine has_any ("--public-key", "/public-key", "--path", "-p ")
   and FolderPath !startswith @"C:\Program Files" 
   and FolderPath !startswith @"C:\Windows\System32";
union ExfilTools, AntiForensics, SuspiciousRust
| project Timestamp, DeviceName, InitiatingProcessAccountName, FileName, ProcessCommandLine, FolderPath
| order by Timestamp desc

-- Hunt for BlackCat (ALPHV) artifacts and Rclone exfil tools
SELECT 
  Pid, 
  Name, 
  CommandLine, 
  Exe, 
  Username, 
  Ctime as CreationTime
FROM pslist()
WHERE Name =~ "rclone.exe" 
   OR Name =~ "vssadmin.exe"
   OR CommandLine =~ "--public-key"
   OR CommandLine =~ "--path"

-- Supplement with file search for unsigned binaries in temp paths
SELECT FullPath, Size, Mtime, Mode
FROM glob(globs="C:\Windows\Temp\*.exe")
WHERE NOT Signed

# BlackCat (ALPHV) Response Hardening Script
# Run with Administrator privileges

Write-Host "[+] Initiating BlackCat Hardening Protocol..." -ForegroundColor Cyan

# 1. Disable Unused Protocols (SMBv1 is often a vector)
Write-Host "[+] Disabling SMBv1..." -ForegroundColor Yellow
Set-SmbServerConfiguration -EnableSMB1Protocol $false -Force

# 2. Stop and Disable Remote Services often abused (e.g., if specific service abuse is detected)
# Note: Do not stop necessary services without validation. 
# This is a generic check for common RMM tools abused in these attacks.
Write-Host "[+] Checking for common RMM tools (AnyDesk, ScreenConnect)..." -ForegroundColor Yellow
$RMMProcesses = @("AnyDesk", "ConnectWise", "RemoteDesktopManager")
foreach ($proc in $RMMProcesses) {
    if (Get-Process -Name $proc -ErrorAction SilentlyContinue) {
        Write-Host "[!] WARNING: $proc is running. Investigate immediately." -ForegroundColor Red
    }
}

# 3. Enable VSS Shadow Copy Protection (Audit)
Write-Host "[+] Verifying VSS Service Status..." -ForegroundColor Yellow
$vssService = Get-Service -Name VSS -ErrorAction SilentlyContinue
if ($vssService.Status -ne "Running") {
    Write-Host "[!] WARNING: Volume Shadow Copy Service is not running. Starting it..." -ForegroundColor Red
    Start-Service -Name VSS
} else {
    Write-Host "[+] VSS Service is Running." -ForegroundColor Green
}

# 4. Block Rclone Execution via AppLocker (if available) or Policy
# Note: Implementation requires actual AppLocker deployment. Below is a placeholder for the logic.
Write-Host "[+] Recommendation: Create AppLocker rule to block rclone.exe in %TEMP% and User Profiles." -ForegroundColor Yellow

Write-Host "[+] Hardening Script Complete." -ForegroundColor Cyan