Security Audit

Security Researcher

Senior-grade security review guidelines anchored on canonical control frameworks: NIST CSF 2.0, CIS Controls v8, NIST SSDF, OWASP ASVS, OWASP Top 10, MITRE ATT&CK, SLSA, and OpenSSF Scorecard.

When to Use

• Security review or audit of code, architecture, or infrastructure
• Threat modeling sessions
• Reviewing PRs for security implications
• Assessing supply chain security
• Smart contract or ZK circuit security reviews

Frameworks Reference

Non-Negotiables

Before any deep review, verify these fundamentals:

1. Asset inventory - Systems, repos, secrets locations, dependencies, owners
2. MFA everywhere - Hardware keys for admins, no shared accounts
3. Patch management - Continuous vuln scanning (OS, containers, deps)
4. Centralized logging - Auth, privilege changes, egress, CI/CD, key access
5. Tested backups - Restore drills, immutable where possible
6. Incident response - Runbooks, on-call, break-glass procedures

Review Methodology

1. Threat Model First

Use STRIDE categories:

• Spoofing - Can attacker impersonate?
• Tampering - Can data be modified?
• Repudiation - Can actions be denied?
• Information disclosure - Data leaks?
• Denial of service - Availability attacks?
• Elevation of privilege - Unauthorized access?

Document for each trust boundary:

• Auth strategy
• Data classification
• Rate limits
• Audit requirements

Assume compromise review:

• If one service key leaks, what's the blast radius?
• If one dependency is malicious, what stops it?

2. Identity & Access (Root Cause #1)

Broken access control is the most common vulnerability.

Check:

• Default-deny authorization (by resource, not just endpoint)
• Short-lived sessions, secure cookies, CSRF protection
• Separation: authentication ≠ authorization ≠ accounting
• Step-up auth for high-risk actions
• RBAC/ABAC with explicit admin boundaries

Protect against:

• Credential stuffing (rate limits, breached password checks)
• Account takeover (MFA, risky-login alerts)
• Session fixation/replay (rotation, binding, nonce/jti)

3. Secrets & Keys

• No secrets in git - Pre-receive hooks, CI secret detectors
• Dedicated KMS/HSM - Least privilege, rotate keys
• Environment separation - Dev/stage/prod with separate creds
• Short-lived credentials - OIDC to cloud, not static keys
• Track usage - Who/what accessed, from where, when
• Compromise playbook - Rotate, revoke, invalidate, postmortem

4. Cryptography

• Use modern primitives (AEAD, not raw AES modes)
• Never roll your own crypto
• CSPRNG for randomness (no time-based seeds)
• Unique nonces where required
• Constant-time ops for secret-dependent paths
• Domain separation for hashes
• Passwords: argon2/bcrypt/scrypt, per-user salt

5. Input Handling & Injection

• Strict allowlists, schema validation at boundaries
• Parameterized queries (no string concatenation)
• Contextual output encoding (HTML/JS/URL)
• SSRF prevention: egress allowlists, metadata IP blocks
• Deserialization: avoid unsafe deserializers, type allowlists
• File uploads: content-type defense, store outside web root

6. Infrastructure

• Asset inventory + secure baseline (golden images)
• Patch SLAs with emergency path
• Network segmentation (prod ≠ CI/CD ≠ corp)
• mTLS for service-to-service
• Rate limits, quotas, circuit breakers
• No public admin panels (VPN + MFA + IP allowlists)

7. CI/CD & Supply Chain

Protect the build pipeline like prod:

• Least privilege runners
• Secrets only in protected contexts
• Reviews for workflow changes

Dependencies:

• Pin versions, verify integrity, monitor CVEs
• Remove abandoned libs

Supply chain:

• Signed build provenance
• OpenSSF Scorecard checks
• SLSA levels adoption

8. Detection & Response

Log with context:

• Auth events, privilege changes, key access
• Config changes, CI/CD events, unusual egress

Protect logs:

• Append-only/immutable, restricted access

Alerting:

• Brute force, impossible travel, new admin grants
• Anomalous token use

Readiness:

• Tabletop exercises, forensic snapshots, kill switches
• Post-incident RCA, patch bug classes

9. Verification

• Code review with security checklists
• SAST + dependency + secret scanning in CI
• DAST for critical surfaces
• Fuzzers on parsers, codecs, serialization
• Abuse case testing (rate limits, replay, permission boundaries)
• External audits for high-risk components
• Bug bounty when mature

Blockchain/Smart Contract Specifics

Protocol & Contracts

• Invariant-first design - Define safety properties, check continuously
• Upgradeability - Timelocks, emergency pause, clear admin key story
• Oracle/bridge threats - Assume counterpart compromise, minimize trust
• Economic attacks - MEV, sandwiching, griefing, liquidity manipulation
• Replay protection - Chain-id, contract address, nonce, EIP-712
• Key custody - Multisig, HSM, threshold signing

ZK Circuits/Provers

• Soundness - Constraints fully bind witness, no unchecked values
• Transcript binding - All public inputs in Fiat-Shamir transcript
• Range/overflow - Explicit range constraints, no wrap assumptions
• Challenges - Derive from transcript, never external mutable sources
• Trusted setup - Ceremony hygiene, reproducible parameters
• Side-channels - Constant-time for secrets, isolate prover infra

Operationalization

1. Pick baselines: CIS v8 + NIST SSDF + OWASP ASVS
2. Map to ATT&CK: What you can't detect, redesign
3. Supply chain: SLSA + Scorecard for repos
4. Loop: Threat model → Controls → Test → Monitor → Drills

Output Format

When conducting a review, structure findings as:

## Finding: [Title]
**Severity**: Critical / High / Medium / Low / Info
**Category**: [STRIDE category or framework reference]
**Location**: [File:line or component]

### Description
[What's wrong]

### Impact
[What could happen]

### Recommendation
[How to fix]

### References
[Framework links, CVE, etc.]

See references/ for detailed checklists by domain.