remediate-gcp-firewall-revoke

name: remediate-gcp-firewall-revoke description: >- Use when a GCP VPC firewall rule has been flagged as opening 0.0.0.0/0 or ::/0 to risky admin / DB / cache ports and you need to contain it. Consumes an OCSF 1.8 Detection Finding (class 2004) emitted by detect-gcp-open-firewall (T1190 Exploit Public-Facing Application) and surgically disables the offending firewall rule via Compute Engine firewalls.patch (default safe action: disabled: true) or, opt-in via --mode delete, removes it via firewalls.delete. Every action is dry-run by default, deny-listed against rule names matching default-*, rules whose description contains intentionally-open, and any rule name in GCP_FIREWALL_REVOKE_DENY_RULE_NAMES. Apply requires GCP_FIREWALL_REVOKE_INCIDENT_ID + GCP_FIREWALL_REVOKE_APPROVER plus an explicit allowed-project binding via GCP_FIREWALL_REVOKE_ALLOWED_PROJECT_IDS. Dual audit (DynamoDB + KMS-encrypted S3, same shared infra as the AWS pair, with provider: "gcp"). Reverify re-reads the rule via firewalls.get and emits VERIFIED if the rule is gone or remains disabled, DRIFT (+ paired OCSF Detection Finding via the shared remediation_verifier contract) if it re-appears or is re-enabled, UNREACHABLE if the Compute API throws. Do NOT use to mass-delete firewall rules, for AWS Security Groups (use remediate-aws-sg-revoke), for Azure Network Security Groups (separate skill planned), to bypass the deny-list, or to operate on rules outside the project the caller has authenticated to. purpose: "Use when a GCP VPC firewall rule has been flagged as opening 0.0.0.0/0 or ::/0 to risky admin / DB / cache ports and you need to contain it. Consumes an OCSF 1.8 Detection Finding (class 2004) emitted by detect-gcp-op..." capability: write-cloud persistence: cloud_state telemetry: stderr_jsonl privilege_escalation: read_write license: Apache-2.0 approval_model: human_required execution_modes: jit, ci, mcp, persistent side_effects: writes-cloud, writes-storage, writes-audit input_formats: ocsf, native output_formats: native concurrency_safety: operator_coordinated network_egress: compute.googleapis.com, s3.amazonaws.com, dynamodb.amazonaws.com caller_roles: security_engineer, incident_responder, platform_engineer approver_roles: security_lead, incident_commander, platform_owner min_approvers: 1 compatibility: >- Requires Python 3.11+, google-api-python-client (lazy-imported only under --apply / --reverify) and boto3 for the shared dual-audit sink. GCP permissions: compute.firewalls.get + compute.firewalls.patch (and compute.firewalls.delete only when --mode delete is used) on the target project. The skill runs under whatever GCP credentials the caller's environment provides; cross-project orchestration belongs in the runner layer. metadata: homepage: https://github.com/msaad00/cloud-ai-security-skills source: https://github.com/msaad00/cloud-ai-security-skills/tree/main/skills/remediation/remediate-gcp-firewall-revoke version: 0.1.0 frameworks: - MITRE ATT&CK v14 - NIST CSF 2.0 - SOC 2 - CIS GCP Foundations cloud: - gcp

remediate-gcp-firewall-revoke

What this closes

Pair skill for detect-gcp-open-firewall (MITRE ATT&CK T1190 — Exploit Public-Facing Application).

This is the GCP counterpart to remediate-aws-sg-revoke. Together with the detector, GCP firewall public exposure becomes a closed loop: detect → contain → audit → re-verify.

Why disable-by-default (not delete)

GCP firewall rules are project-scoped, named, and frequently referenced by infrastructure-as-code, attached service descriptions, and operator playbooks. Deleting a rule by name is a destructive change that loses history and breaks references. The default action is firewalls.patch with disabled: true, which immediately stops the rule from granting traffic but preserves the object for forensics and rollback. Use --mode delete only when the operator explicitly accepts that loss of history.

Inputs

OCSF 1.8 Detection Finding (class 2004) from detect-gcp-open-firewall. Required observables:

• target.uid — the firewall rule name (REQUIRED)
• target.name — same as target.uid for GCP
• account.uid — the GCP project id (REQUIRED for audit context)
• permission.cidr[], permission.port[] — what the offending grant covers
• actor.name, rule — audit context

Do NOT use

• To mass-delete firewall rules (this skill is finding-driven and one-rule-at-a-time)
• For AWS Security Groups (use remediate-aws-sg-revoke)
• For Azure Network Security Groups (separate skill planned)
• To bypass the deny-list, run --apply without an explicit human-approved incident window, or edit the audit trail by hand
• For audit/discovery — this skill writes; for inventory use discover-environment
• For rules outside the project the caller has authenticated to

Guardrails (enforced in code)

Run

# Dry-run plan (default)
python skills/remediation/remediate-gcp-firewall-revoke/src/handler.py findings.ocsf.jsonl

# Apply (default mode = patch with disabled: true)
export GOOGLE_APPLICATION_CREDENTIALS=/path/to/sa.json
export GCP_FIREWALL_REVOKE_INCIDENT_ID=INC-2026-04-19-006
export GCP_FIREWALL_REVOKE_APPROVER=alice@security
export GCP_FIREWALL_REVOKE_ALLOWED_PROJECT_IDS=my-prod-project
export GCP_FIREWALL_REVOKE_AUDIT_DYNAMODB_TABLE=gcp-firewall-revoke-audit
export GCP_FIREWALL_REVOKE_AUDIT_BUCKET=acme-gcp-firewall-audit
export KMS_KEY_ARN=arn:aws:kms:us-east-1:111122223333:key/...
# Optional: pin rule names that should never be auto-revoked
export GCP_FIREWALL_REVOKE_DENY_RULE_NAMES=allow-ops-bastion,allow-internal-lb
python skills/remediation/remediate-gcp-firewall-revoke/src/handler.py findings.ocsf.jsonl --apply

# Apply with delete (opt-in, more destructive)
python skills/remediation/remediate-gcp-firewall-revoke/src/handler.py findings.ocsf.jsonl --apply --mode delete

# Re-verify (read-only)
python skills/remediation/remediate-gcp-firewall-revoke/src/handler.py findings.ocsf.jsonl --reverify

Required GCP IAM

The execution principal needs these Compute Engine permissions on the target project:

• compute.firewalls.get — for re-verify and pre-check
• compute.firewalls.patch — for default --mode patch (set disabled: true)
• compute.firewalls.delete — only when --mode delete is used

These are all included in the predefined role roles/compute.securityAdmin. A least-privilege custom role with just the three permissions above is the recommended path.

Non-goals

• Deleting all firewall rules in a project (one-rule-at-a-time, finding-driven)
• Tag-based discovery of rules to revoke (this skill is finding-driven)
• Cross-project auto-revoke (the skill now fails closed unless the target project is named explicitly in GCP_FIREWALL_REVOKE_ALLOWED_PROJECT_IDS)
• Posture-at-rest scanning (use cspm-gcp-cis-benchmark)

See also

• detect-gcp-open-firewall — paired source detector
• remediate-aws-sg-revoke — AWS counterpart
• remediate-okta-session-kill, remediate-k8s-rbac-revoke, remediate-entra-credential-revoke — sibling closed-loop remediation skills
• _shared/remediation_verifier.py — verification contract
• docs/HITL_POLICY.md — repo-wide HITL bar