How 2026’s Least-Prevented Ransomware Families Evade Defenses

Summary

This report examines ten ransomware families with the lowest prevention scores in 2026, focusing on the advanced evasion tradecraft they use to bypass defenses. The analysis highlights Stealth and Defense Impairment tactics designed to weaken security controls. Common techniques include obfuscation, process injection, and disabling security tools.

Investigation

The investigation draws on data from the Picus Blue Report, an annual data-driven assessment of real-world attack techniques tested against production security controls. Researchers mapped the behaviors of the ten least-prevented ransomware families to the MITRE ATT&CK framework. The study specifically evaluated how these threats apply Stealth and Defense Impairment techniques.

Mitigation

Mitigation should include validating prevention and detection controls through Breach and Attack Simulation (BAS). Organizations need to reduce the gap between perceived protection and actual control effectiveness. Defenders should prioritize detecting obfuscation, registry modification, and attempts to tamper with security telemetry.

Response

If these behaviors are detected, responders should investigate for ETW patching, process injection, and unauthorized termination of security services. Forensic timelines may be affected by timestomping and event log clearing. Immediate isolation of impacted systems and verification of backup integrity are strongly recommended.

Simulation Execution

Prerequisite: The Telemetry & Baseline Pre-flight Check must have passed.

Rationale: This section details the precise execution of the adversary technique (TTP) designed to trigger the detection rule. The commands and narrative MUST directly reflect the TTPs identified and aim to generate the exact telemetry expected by the detection logic. Abstract or unrelated examples will lead to misdiagnosis.

• Attack Narrative & Commands: The adversary aims to deploy ransomware by masquerading as a legitimate system update. They use msiexec.exe to run a remote .msi file silently (/qn), a common technique to avoid user interaction. Simultaneously, to download the final payload, they use a highly obfuscated PowerShell command where the payload string is hidden within a byte array and reconstructed using iex (Invoke-Expression) to evade simple string-based detection. This mimics the behavior of families like Magniber.

• Regression Test Script:

    # Simulation Script: Ransomware Command Obfuscation
    # This script generates the specific strings targeted by the detection rule.
  
    Write-Host "[+] Starting Simulation..."
  
    # 1. Simulate msiexec pattern
    # Note: We use a dummy path to satisfy the 'contains all' logic requirements.
    $dummyPath = "C:UsersPublicsetup.msi"
    Start-Process "msiexec.exe" -ArgumentList "/i `"$dummyPath`" /qn" -Wait
    Write-Host "[+] Executed msiexec simulation."
  
    # 2. Simulate Obfuscated PowerShell pattern
    # This mimics the exact logic: powershell iex(-JOIN((112,97,121,108,111,100,...)))
    # Note: The rule expects a specific substring pattern.
    $obfuscatedCmd = "powershell.exe -ExecutionPolicy Bypass -Command `"iex(-JOIN((112,97,121,108,111,97,100,101,114,44,32,116,104,101,44,32,100,97,116,97))))`""
    Start-Process "powershell.exe" -ArgumentList "-Command $obfuscatedCmd"
    Write-Host "[+] Executed obfuscated PowerShell simulation."
  
    # 3. Simulate Process Injection Command String (Simulated via command line argument)
    # The rule looks for: 'CreateProcess("...", CREATE_SUSPENDED) -> patch PEB->CommandLine -> ResumeThread'
    $injectionCmd = "cmd.exe /c `"CreateProcess('...', CREATE_SUSPENDED) -> patch PEB->CommandLine -> ResumeThread`""
    Start-Process "cmd.exe" -ArgumentList "/c $injectionCmd"
    Write-Host "[+] Executed injection string simulation."
  
    Write-Host "[+] Simulation Complete."

• Cleanup Commands:

    # Cleanup script to remove any artifacts created during simulation
    Remove-Item -Path "C:UsersPublicsetup.msi" -ErrorAction SilentlyContinue
    Write-Host "[+] Cleanup complete."