implementing-gcp-vpc-firewall-rules

name	implementing-gcp-vpc-firewall-rules
description	Implementing and auditing GCP VPC firewall rules to enforce network segmentation, restrict ingress and egress traffic, apply hierarchical firewall policies across the organization, and monitor firewall rule effectiveness using VPC Flow Logs. . Use when working with implementing gcp vpc firewall rules.
domain	cybersecurity
tags	["cloud-security","gcp","vpc","firewall-rules","network-security","segmentation"]
subdomain	cloud-security
version	1.0
author	oyi77
license	Apache-2.0
nist_csf	["PR.IR-01","ID.AM-08","GV.SC-06","DE.CM-01"]

Implementing Gcp Vpc Firewall Rules

Overview

Cybersecurity skill for implementing gcp vpc firewall rules. Follows industry best practices and security standards.

When to Use

Trigger phrases:

• "implementing gcp vpc firewall rules"

• "Implementing and auditing GCP VPC firewall rules to enforce network segmentation"

• When deploying new GCP workloads that require network-level access controls

• When auditing existing firewall configurations for overly permissive rules

• When implementing zero trust network segmentation within GCP VPC networks

• When responding to Security Command Center findings about open firewall rules

• When building hierarchical firewall policies across a GCP organization

Do not use for application-layer filtering (use Cloud Armor WAF), for DNS-based filtering (use Cloud DNS response policies), or for VPN/interconnect traffic filtering without understanding that VPC firewall rules apply to traffic within the VPC.

When NOT to Use

• When you lack proper authorization for testing
• For production systems without change management
• When the task requires legal or compliance expertise beyond technical scope

Prerequisites

• GCP project with Compute Engine API enabled
• IAM roles: roles/compute.securityAdmin for firewall management, roles/compute.networkViewer for auditing
• Organization Admin role for hierarchical firewall policies
• gcloud CLI authenticated with appropriate permissions
• VPC Flow Logs enabled on target subnets for monitoring

Workflow

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: ) -> :
     {k: re.findall(v, text)  k, v  IOC_PATTERNS.items()}