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Firewall & Security

Block SMB Port 445

Block incoming SMB traffic on port 445 to prevent ransomware attacks

Benefit

Significantly improves security by blocking major attack vector for ransomware and worms

Impact

high

Commands (1)

$ErrorActionPreference='Continue'; $name = 'CodeWinOpt-Block-SMB-445'; $r = Get-NetFirewallRule -DisplayName $name -ErrorAction SilentlyContinue; if ($r) { Write-Host "[OK] Rule '$name' already exists" } else { try { New-NetFirewallRule -DisplayName $name -Direction Inbound -Action Block -Protocol TCP -LocalPort 445 -Profile Any -Description 'Block inbound SMB on port 445 (CodeWinOptimizer)' -ErrorAction Stop | Out-Null; Write-Host "[OK] Created firewall rule '$name' blocking inbound TCP 445" } catch { Write-Host "[ERR] $($_.Exception.Message)" } }

Warnings

  • Port 445 is the primary vector for ransomware propagation on Windows networks. Blocking is highly recommended unless you require SMB shares.