Canada Disrupts Encryption-Based Ops: Ransomware Detection and Hardening

This week in cybersecurity highlights a critical convergence of threats: the breach of a DHS database, a massive data breach at AssuranceAmerica affecting 7 million individuals, and the disruption of "encryption-based cyber incident operations" (ransomware) by Canadian authorities. The return of the NSA's Tailored Access Operations (TAO) further signals an elevated threat landscape from both criminal and nation-state actors.

For defenders, the headline regarding the disruption of encryption-based ops is a call to action. While the specific infrastructure was seized, the tactics remain active. We must assume that threat actors are continuing to attempt encryption-based attacks. This post focuses on the technical execution of these incidents, specifically the anti-forensics and data destruction mechanisms that precede encryption, and provides actionable detection logic and hardening steps.

Technical Analysis

Threat Overview

The news item describes "encryption-based cyber incident operations," which is the standard terminology for modern ransomware campaigns. These attacks typically follow a Kill Chain: Initial Access (often via vulnerabilities like those Adobe is rushing to patch, or credential theft), Execution, Defense Evasion, and Impact (Encryption).

Attack Mechanics and Affected Components

While the specific CVE utilized in the mentioned operations was not disclosed in the report, the technique of encryption-based attacks involves distinct, observable behaviors on Windows endpoints:

1. Shadow Copy Deletion: To prevent recovery via Windows Volume Shadow Copy Service (VSS), actors utilize vssadmin.exe or wmic.exe to delete shadow copies before encryption begins.
2. Log Clearing: To erase forensic evidence, attackers frequently use wevtutil.exe to clear Windows Event Logs (System, Security, Application).
3. Service Termination: Security agents and backup services are stopped to ensure encryption succeeds without interference.

Exploitation Status

Active. The "encryption-based" nature of the disrupted ops confirms that ransomware-as-a-service (RaaS) or custom encryption payloads are in active use. The breach of the DHS database and AssuranceAmerica suggests that data exfiltration often accompanies or precedes the encryption phase (Double Extortion).

Detection & Response

To defend against these encryption-based operations, we must detect the precursor activities—specifically the destruction of recovery mechanisms. The following rules target the anti-forensics stage common to these incidents.

SIGMA Rules

---
title: Potential Ransomware Anti-Forensics - VSS Deletion
id: 9a5a7b2c-1d3e-4f5a-9b6c-1d2e3f4a5b6c
status: experimental
description: Detects attempts to delete Volume Shadow Copies using vssadmin or wmic, a common precursor to encryption-based ransomware attacks.
references:
  - https://attack.mitre.org/techniques/T1490/
author: Security Arsenal
date: 2026/04/22
tags:
  - attack.impact
  - attack.t1490
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\vssadmin.exe'
      - '\wmic.exe'
    CommandLine|contains:
      - 'delete shadows'
      - 'shadowstorage delete'
  condition: selection
falsepositives:
  - Legitimate system administration or backup management
level: high
---
title: Potential Ransomware Anti-Forensics - Event Log Clearing
id: 8b4c6a1d-2e4f-5a6b-7c8d-9e0f1a2b3c4d
status: experimental
description: Detects the use of wevtutil to clear event logs, often performed by ransomware to hinder incident response.
references:
  - https://attack.mitre.org/techniques/T1070/
author: Security Arsenal
date: 2026/04/22
tags:
  - attack.defense_evasion
  - attack.t1070.001
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\wevtutil.exe'
    CommandLine|contains:
      - 'cl '
      - 'clear-log '
  condition: selection
falsepositives:
  - Rare administrative log clearing tasks
level: high

KQL (Microsoft Sentinel / Defender)

// Hunt for VSS deletion and log clearing patterns associated with encryption-based attacks
DeviceProcessEvents
| where Timestamp > ago(7d)
| where (FileName in~ ("vssadmin.exe", "wmic.exe") and ProcessCommandLine has_any ("delete shadows", "shadowstorage delete"))
   or (FileName == "wevtutil.exe" and ProcessCommandLine has_any ("cl ", "clear-log "))
| project Timestamp, DeviceName, AccountName, FileName, ProcessCommandLine, InitiatingProcessFileName
| order by Timestamp desc

Velociraptor VQL

-- Hunt for processes attempting to delete shadow copies or clear logs
SELECT Pid, Name, CommandLine, Exe, Username, CreateTime
FROM pslist()
WHERE Name =~ 'vssadmin'
   AND CommandLine =~ 'delete shadows'
   OR Name =~ 'wmic'
   AND CommandLine =~ 'shadowcopy delete'
   OR Name =~ 'wevtutil'
   AND CommandLine =~ 'cl'

Remediation Script (PowerShell)

# Remediation: Verify and Enable Volume Shadow Copy Protection
# Run as Administrator

Write-Host "Checking VSS Service Status..."
$vssService = Get-Service -Name VSS -ErrorAction SilentlyContinue
if ($vssService.Status -ne 'Running') {
    Write-Host "Starting VSS Service..."
    Start-Service -Name VSS
}

Write-Host "Verifying Shadow Copy Storage Association on C:"
# Check if Shadow Copies are enabled
try {
    $vssOutput = vssadmin list shadowstorage
    if ($vssOutput -match "No shadow copies found") {
        Write-Warning "Shadow copies are currently disabled. Enabling a schedule for protection is recommended."
        # Note: Enabling requires a schedule via 'vssadmin add shadowstorage' or Group Policy.
        # This script verifies the state. Manual intervention may be required to set storage limits.
    } else {
        Write-Host "Shadow Copy Storage Configuration Found:"
        Write-Host $vssOutput
    }
} catch {
    Write-Error "Failed to query VSS status: $_"
}

Remediation

1. Immediate Patching: As noted in the news, Adobe has boosted its patch cadence. Ensure Adobe Acrobat, Reader, and other widely targeted applications are updated to the latest versions immediately. Unpatched software remains the primary vector for initial access.
2. Disable Unused VSS Admin Access: Restrict access to vssadmin.exe and wmic.exe for non-administrative users via Software Restriction Policies (SRP) or AppLocker.
3. Immutable Backups: Given the "encryption-based" nature of the threat, ensure you have offline or immutable backups (WORM storage) that cannot be deleted or encrypted even if the VSS is destroyed.
4. Review DHS & AssuranceAmerica Notifications: If your organization interacts with DHS or AssuranceAmerica, treat this as a compromise indicator and initiate credential rotation and hunting for IoCs associated with supply chain or credential stuffing attacks.

Related Resources

Security Arsenal Incident Response Services AlertMonitor Platform Book a SOC Assessment incident-response Intel Hub