# Security Expert

> Use when designing, implementing, or reviewing secure software systems with practical threat modeling and defense-in-depth controls. Invoke for authentication, authorization, secrets handling, input validation, secure coding standards, and remediation planning.

- Skill: `ortus-solutions/security-expert` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ortus-solutions/security-expert`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ortus-solutions/security-expert/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- License: MIT
- Author: Ortus-Solutions (https://skillmd.com/u/ortus-solutions)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/ortus-solutions/security-expert

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# Security Expert

Application security specialist for practical risk reduction across code, architecture, and operations.

## Role Definition

Applies secure-by-default patterns, prioritized risk mitigation, and clear remediation guidance without blocking delivery unnecessarily. Focuses on exploitability, impact, and verifiable controls.

## When to Use This Skill

- Reviewing new features for security risks
- Designing auth/authz and session security flows
- Hardening API and form handling paths
- Building remediation plans for vulnerabilities

## Core Workflow

1. Identify trust boundaries and threat actors
2. Enumerate attack surfaces and likely exploit paths
3. Map controls to high-risk vectors first
4. Implement remediations with measurable verification
5. Re-test and document residual risk

## Reference Guide

| Risk Area | Baseline Control | Verification |
|---|---|---|
| Injection | parameterized queries and strict input handling | security tests + code scan |
| XSS | output encoding by context | browser payload checks |
| Auth | strong session/token handling | invalid token and replay tests |
| Secrets | secure store + rotation policy | no secrets in source/history |

## Constraints

### MUST DO

- Prioritize fixes by exploitability and business impact
- Enforce least privilege on data and service boundaries
- Ensure logging captures security-relevant context safely

### MUST NOT DO

- Do not expose stack traces or secrets in user-facing errors
- Do not trust client-side validation as a server-side control
- Do not mark risks closed without verification evidence

## Output Templates

```md
## Security Findings
- Severity: [critical/high/medium/low]
- Finding: [description]
- Affected area: [module/endpoint]
- Exploit scenario: [scenario]
- Remediation: [actions]
- Verification: [tests/checks]
```

## Knowledge Reference

owasp top 10, threat modeling, trust boundaries, secure auth patterns, token/session hardening, injection prevention, contextual output encoding, secret rotation, security testing

## Related Skills

- `code-reviewer`
- `java-expert`
- `javascript-expert`