Performing GCP Penetration Testing With Gcpbucketbrute

Performing GCP Penetration Testing with GCPBucketBrute

Overview

This skill covers Google Cloud Platform security testing using GCPBucketBrute for storage bucket enumeration and access permission testing, combined with gcloud CLI IAM enumeration to identify privilege escalation paths. The approach tests for publicly accessible buckets, overly permissive IAM bindings, and service account key exposure.

When to Use

Trigger phrases:

• "performing gcp penetration testing with gcpbucketbrute"

• "Perform GCP security testing using GCPBucketBrute for storage bucket enumeration"

• When conducting security assessments that involve performing gcp penetration testing with gcpbucketbrute

• When following incident response procedures for related security events

• When performing scheduled security testing or auditing activities

• When validating security controls through hands-on testing

Prerequisites

• Python 3.8+ with google-cloud-storage library
• GCPBucketBrute installed from RhinoSecurityLabs GitHub
• gcloud CLI authenticated with test credentials
• Authorized penetration testing scope for target GCP project
• google-api-python-client and google-auth libraries

Steps

# 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: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}

1. Enumerate Storage Buckets — Use GCPBucketBrute with keyword permutations to discover accessible GCP storage buckets
2. Test Bucket Permissions — Call TestIamPermissions API on each discovered bucket to determine read/write/admin access levels
3. Audit IAM Bindings — Enumerate project-level IAM policies to identify overly permissive role bindings
4. Check Service Account Keys — Identify service accounts with user-managed keys and test for privilege escalation via impersonation
5. Test Privilege Escalation Paths — Check for iam.serviceAccounts.actAs, setIamPolicy, and other privilege escalation vectors
6. Generate Findings Report — Produce a structured security assessment with risk severity ratings

Expected Output

• JSON report of discovered buckets with permission levels
• IAM privilege escalation path analysis
• Service account security assessment
• Risk-scored findings with remediation recommendations

When NOT to Use

• You don't have explicit written authorization to test
• Task is about defense/detection, not offense (use detection skills)
• You need to implement security controls (use implementing-* skills)
• Task requires compliance auditing (use auditing-* skills)
• You're investigating an incident (use incident response skills)
• Target is out of scope for your engagement
• Task is about vulnerability scanning only (use scanning tools)

Red Flags

• Performing actions without explicit written authorization from the asset owner
• Testing against production systems without a defined scope and rules of engagement
• Exceeding the authorized scope of the engagement
• Leaving persistent access mechanisms without explicit approval
• Causing denial-of-service on production systems during testing

Process

1. Design — Define interface, identify patterns, plan implementation
2. Implement — Write code following existing conventions, add tests
3. Verify — Run tests, check integration, validate behavior

Verification

• All steps executed successfully against a test environment before production use
• Output documented with screenshots or logs demonstrating expected behavior
• All exploited vulnerabilities documented with reproduction steps
• Scope boundaries confirmed — only authorized targets were tested
• Remediation recommendations included for every finding

Anti-Rationalization Table