Ensure RDP access is restricted from the Internet

AltaNivel 2Automatizadagcp

Descripción

Firewall rules allowing RDP (3389) from 0.0.0.0/0 or ::/0 expose every targeted VM to brute force. No enabled INGRESS rule may allow tcp/udp port 3389 (or all) from those ranges. Read-only gcloud calls against the active project (gcloud config set project, or CLOUDSDK_CORE_PROJECT); credentials come from the SDK's normal configuration (gcloud auth login, a service account or ADC). A missing CLI, credential or disabled API fails the check.

Cómo se verifica

Método de auditoría: Comando de shell

shell

out=$(gcloud compute firewall-rules list --format='value(name,direction,disabled,sourceRanges.list(),allowed[].map().firewall_rule().list())' 2>/dev/null) || exit 1
printf '%s\n' "$out" | awk -F '\t' -v p=3389 '
function hit(s,   n, i, a, b, m, pr) { n = split(s, a, ","); pr = ""; for (i = 1; i <= n; i++) { m = a[i]; if (m ~ /^[a-z]/) { pr = m; sub(/:.*/, "", pr); if (m !~ /:/) { if (pr == "all" || pr == "tcp" || pr == "udp") return 1; continue } sub(/^[^:]*:/, "", m) } if (pr != "tcp" && pr != "udp") continue; if (split(m, b, "-") == 2) { if (p >= b[1] + 0 && p <= b[2] + 0) return 1 } else if (m + 0 == p) return 1 } return 0 }
NF && $2 == "INGRESS" && $3 != "True" && ("," $4 ",") ~ /,(0\.0\.0\.0\/0|::\/0),/ && hit($5) { n++; print "open: " $1 }
END { if (!n) print "compliant" }'

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

Restrict the listed rules to specific source ranges (gcloud compute firewall-rules update <rule> --source-ranges=<cidrs>) or delete them; use IAP TCP forwarding (35.235.240.0/20) for RDP instead.

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: gcpnetwork
Referencia: CIS Google Cloud Platform Foundation Benchmark v5.0.0 - Networking - RDP access restricted from the Internet (verify section number for your release)

Verificar este host

Ejecute esto en un equipo que tenga permiso para auditar. El escaneo es de solo lectura.

shell

tmaegis scan --target gcp --level 2