Aegis Protocol

Security review skill for changed code only. This workflow is tuned for high-confidence findings, low noise, and modern attacker-informed prioritization.

Use when

• User asks for security review of a PR, branch, or diff.
• You need exploit-focused findings, not a general code review.
• You must filter speculative issues before reporting.

Do not use when

• The request is a full quality review (use regular code review workflow).
• The target has no meaningful code changes yet.

Inputs

• Git base reference (default origin/HEAD)
• Changed files and diff
• Optional runtime architecture and trust boundaries
• Optional custom security policies

Workflow

Phase 1: Collect change scope

Run:

git status
git diff --name-only origin/HEAD...
git log --no-decorate origin/HEAD...
git diff --merge-base origin/HEAD

Rules:

• Review only newly introduced security risk in changed code.
• Ignore pre-existing vulnerabilities outside the change scope.
• Prioritize server, auth, crypto, data-access, deserialization, and command execution paths.

Phase 2: Threat context (modern methodology layer)

For each changed security-relevant path:

• Identify attacker-controlled inputs, trust boundaries, and privilege transitions.
• Map likely attacker behavior to MITRE ATT&CK tactics/techniques when possible.
• Tag weakness classes using OWASP Top 10:2025 and CWE terminology.
• For application control gaps, map to OWASP ASVS v5 requirement IDs when practical.
• For build/dependency/provenance changes, check supply-chain risk using SLSA and existing CI trust assumptions.

Then inspect repository context:

• Existing validation and sanitization patterns
• Existing auth and permission boundaries
• Existing secret management conventions
• Existing secure build and release practices

Look for concrete vulnerabilities in changed code:

• Injection: SQL, command, template, NoSQL, path traversal, XXE
• AuthZ/AuthN: bypasses, privilege escalation, broken session checks
• Crypto/secrets: hardcoded secrets, weak algorithms, cert validation bypass
• Code execution: unsafe deserialization, eval-like execution, unsafe shell execution
• Data exposure: sensitive logging, over-broad API responses, PII leaks
• Supply chain: unsigned/unverified artifacts, unsafe dependency ingestion, provenance gaps

Phase 3: Exploitability proof gate

A candidate vulnerability must include all of:

• Entry point attacker can influence
• Reachable vulnerable operation in changed code
• Missing or bypassed security control
• Credible impact path

If any element is missing, do not report.

Phase 4: Prioritization layer

Use High/Medium severity only, then enrich urgency using:

• KEV signal: If affected component/CVE is in CISA KEV, prioritize immediate remediation.
• SSVC action framing: Track, Attend, or Act to guide operational urgency.
• CVSS v4 lens: Include Base + Threat thinking where exploit maturity is known.

These signals improve prioritization only; they do not override confidence policy.

Phase 5: False-positive filter (mandatory)

Hard exclusions:

• DOS/resource exhaustion/rate limiting concerns
• Theoretical race conditions without concrete exploit path
• Pure hardening gaps without concrete vulnerability
• Dependency outdatedness findings handled by other tooling
• Test-only files and documentation files
• Client-side-only auth checks as a primary finding
• Regex injection/ReDoS as standalone report

Confidence policy:

• Report only findings with confidence >= 8/10
• Prefer missing weak findings over reporting noisy findings

Phase 6: Remediation quality gate

For each finding, provide:

• Immediate code-level fix
• Durable prevention recommendation tied to SSDF/Secure-by-Design mindset
• Concrete verification step (test/assertion/check)

Output format

Return markdown findings only, one section per issue:

# Vuln 1: <Category>: `<file>:<line>`
* Severity: High|Medium
* Confidence: 8-10
* Methodology Mapping: ATT&CK (if applicable), OWASP Top 10:2025, CWE, ASVS v5 (if applicable)
* Priority Signal: KEV=<Yes|No>; SSVC=<Track|Attend|Act>; CVSSv4-Lens=<short note>
* Description: Concrete vulnerability summary
* Exploit Scenario: Specific attack path
* Recommendation: Practical fix in this codebase
* Verification: Specific way to validate the fix

If no qualifying findings:

No high-confidence security vulnerabilities found in the reviewed changes.

Severity policy

• High: exploitable for unauthorized access, data breach, system compromise
• Medium: concrete vulnerability with meaningful impact but stricter conditions
• Low: do not report

Quick prompts

• Run Aegis Protocol on current branch vs origin/HEAD
• Security-review this PR diff with confidence >= 8 only
• Audit changed files for auth bypass, injection, and data exposure only
• Run Aegis with ATT&CK/OWASP/CWE mapping and SSVC-style priority signals

Anti-patterns

• Reporting speculative vulnerabilities without exploit path
• Reviewing the entire repository when only diff review is requested
• Mixing style/performance feedback into security results
• Emitting findings without precise file and line references

Reference

• Anthropic reference workflow: anthropics/claude-code-security-review
• Local note: references/security-rubric.md
• Modern methodology map: references/modern-methodologies.md