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Software Security & AppSec — Quick Reference

Production-grade security patterns for building secure applications in Jan 2026. Covers OWASP Top 10:2025 (stable) https://owasp.org/Top10/2025/ plus OWASP API Security Top 10 (2023) https://owasp.org/API-Security/ and secure SDLC baselines (NIST SSDF) https://csrc.nist.gov/publications/detail/sp/800-218/final.

When to Use This Skill

Activate this skill when:

• Implementing authentication or authorization systems
• Handling user input that could lead to injection attacks (SQL, XSS, command injection)
• Designing secure APIs or web applications
• Working with cryptographic operations or sensitive data storage
• Conducting security reviews, threat modeling, or vulnerability assessments
• Responding to security incidents or compliance audit requirements
• Building systems that must comply with OWASP, NIST, PCI DSS, GDPR, HIPAA, or SOC 2
• Integrating third-party dependencies (supply chain security review)
• Implementing zero trust architecture or modern cloud-native security patterns
• Establishing or improving secure SDLC gates (threat modeling, SAST/DAST, dependency scanning)

When NOT to Use This Skill

• General backend development without security focus → use software-backend
• Infrastructure/cloud security (IAM, network security, container hardening) → use ops-devops-platform
• Smart contract auditing as primary focus → use software-crypto-web3
• ML model security (adversarial attacks, data poisoning) → use ai-mlops
• Compliance-only questions without implementation → consult compliance team directly

Quick Reference Table

Authentication Decision Matrix (Jan 2026)

Jurisdiction notes (verify): Authentication assurance requirements vary by country, industry, and buyer. Prefer passkeys/FIDO2; treat SMS OTP as recovery-only/low assurance unless you can justify it.

OWASP Top 10:2025 Quick Checklist

| Risk | Key Controls | Test

---|---|---|---
A01 | Broken Access Control | RBAC/ABAC, deny by default, CORS allowlist | BOLA, BFLA, privilege escalation
A02 | Security Misconfiguration | Harden defaults, disable unused features, error handling | Default creds, stack traces, headers
A03 | Supply Chain Failures (NEW) | SBOM, dependency scanning, SLSA, code signing | Outdated deps, typosquatting, compromised packages
A04 | Cryptographic Failures | TLS 1.3, AES-256-GCM, key rotation, no MD5/SHA1 | Weak ciphers, exposed secrets, cert validation
A05 | Injection | Parameterized queries, input validation, output encoding | SQLi, XSS, command injection, LDAP injection
A06 | Insecure Design | Threat modeling, secure design patterns, abuse cases | Design flaws, missing controls, trust boundaries
A07 | Authentication Failures | MFA/passkeys, rate limiting, secure password storage | Credential stuffing, brute force, session fixation
A08 | Integrity Failures | Code signing, CI/CD pipeline security, SRI | Unsigned updates, pipeline poisoning, CDN tampering
A09 | Logging Failures | Structured JSON, SIEM integration, correlation IDs | Missing logs, PII in logs, no alerting
A10 | Exceptional Conditions (NEW) | Fail-safe defaults, complete error recovery, input validation | Error handling gaps, fail-open, resource exhaustion

Decision Tree: Security Implementation

Security requirement: [Feature Type]
    ├─ User Authentication?
    │   ├─ Session-based? → Cookie sessions + CSRF tokens
    │   ├─ Token-based? → JWT with refresh tokens (references/authentication-authorization.md)
    │   └─ Third-party? → OAuth2/OIDC integration
    │
    ├─ User Input?
    │   ├─ Database query? → Parameterized queries (NEVER string concatenation)
    │   ├─ HTML output? → DOMPurify sanitization + CSP headers
    │   ├─ File upload? → Content validation, size limits, virus scanning
    │   └─ API parameters? → Allowlist validation (references/input-validation.md)
    │
    ├─ Sensitive Data?
    │   ├─ Passwords? → bcrypt/Argon2 (cost factor 12+)
    │   ├─ PII/financial? → AES-256-GCM encryption + key rotation
    │   ├─ API keys/tokens? → Environment variables + secrets manager
    │   └─ In transit? → TLS 1.3 only
    │
    ├─ Access Control?
    │   ├─ Simple roles? → RBAC (assets/web-application/template-authorization.md)
    │   ├─ Complex rules? → ABAC with policy engine
    │   └─ Relationship-based? → ReBAC (owner, collaborator, viewer)
    │
    └─ API Security?
        ├─ Public API? → Rate limiting + API keys
        ├─ CORS needed? → Strict origin allowlist (never *)
        └─ Headers? → Helmet.js (CSP, HSTS, X-Frame-Options)

Security ROI & Business Value (Jan 2026)

Security investment justification and compliance-driven revenue. Full framework: references/security-business-value.md

Quick Breach Cost Reference

Indicative figures (source: IBM Cost of a Data Breach 2024; refresh for current year): https://www.ibm.com/reports/data-breach

Compliance → Enterprise Sales

ROI Formula (Quick Reference)

Security ROI = (Risk Reduction - Investment) / Investment × 100

Risk Reduction = Breach Probability × Avg Cost × Control Effectiveness
Example: 15% × $4.88M × 46% = $337K/year risk reduction

Incident Response Patterns (Jan 2026)

Security Incident Playbook

Security Logging Requirements

Do:

• Include correlation IDs across services
• Log to SIEM (Splunk, Datadog, ELK)
• Mask PII in logs

Avoid:

• Logging passwords, tokens, or keys
• Unstructured log formats
• Missing timestamps or context

Common Security Mistakes

Optional: AI/Automation Extensions

Note : Security considerations for AI systems. Skip if not building AI features.

LLM Security Patterns

AI-Assisted Security Tools

.NET/EF Core Crypto Integration Security

For C#/.NET crypto/fintech services using Entity Framework Core, see:

• references/dotnet-efcore-crypto-security.md — Security rules and C# patterns

Key rules summary:

• No secrets in code — use configuration/environment variables
• No sensitive data in logs (tokens, keys, PII)
• Use decimal for financial values, never double/float
• EF Core or parameterized queries only — no dynamic SQL
• Generic error messages to users, detailed logging server-side

Navigation

Core Resources (Updated 2024-2026)

Security Business Value & ROI

• references/security-business-value.md — Breach cost modeling, security ROI formulas, compliance → enterprise sales, investment justification templates

2025 Updates & Modern Architecture

• references/supply-chain-security.md — Dependency, build, and artifact integrity (SLSA, provenance, signing)
• references/zero-trust-architecture.md — NIST SP 800-207, service identity, policy-based access
• references/owasp-top-10.md — OWASP Top 10:2025 (final) guide + 2021→2025 diffs
• references/advanced-xss-techniques.md — 2024-2025 XSS: mutation XSS, polyglots, SVG attacks, context-aware encoding

API Security, Incident Response & Threat Modeling

• references/api-security-patterns.md — OWASP API Security Top 10, BOLA/BFLA, rate limiting, API keys, GraphQL/gRPC security
• references/incident-response-playbook.md — IR team roles, severity triage, containment by incident type, evidence handling, communication templates, postmortem
• references/threat-modeling-guide.md — STRIDE, PASTA, data flow diagrams, attack trees, risk scoring (CVSS/DREAD), lightweight agile threat modeling

Foundation Security Patterns

• references/secure-design-principles.md — Defense in depth, least privilege, secure defaults
• references/authentication-authorization.md — AuthN/AuthZ flows, OAuth 2.1, JWT best practices, RBAC/ABAC
• references/input-validation.md — Allowlist validation, SQL injection, XSS, CSRF prevention, file upload security
• references/cryptography-standards.md — AES-256-GCM, Argon2, TLS 1.3, key management
• references/common-vulnerabilities.md — Path traversal, command injection, deserialization, SSRF

External References

• data/sources.json — 70+ curated security resources (OWASP 2025, supply chain, zero trust, API security, compliance)
• Shared checklists: ../software-clean-code-standard/assets/checklists/secure-code-review-checklist.md, ../software-clean-code-standard/assets/checklists/backend-api-review-checklist.md

Templates by Domain

Web Application Security

• assets/web-application/template-authentication.md — Secure authentication flows (JWT, OAuth2, sessions, MFA)
• assets/web-application/template-authorization.md — RBAC/ABAC/ReBAC policy patterns

API Security

• assets/api/template-secure-api.md — Secure API gateway, rate limiting, CORS, security headers

Cloud-Native Security

• assets/cloud-native/crypto-security.md — Cryptography usage, key management, HSM integration

Blockchain & Web3 Security

• references/smart-contract-security-auditing.md — NEW : Smart contract auditing, vulnerability patterns, formal verification, Solidity security

Related Skills

Security Ecosystem

• ../software-backend/SKILL.md — API implementation patterns and error handling
• ../software-architecture-design/SKILL.md — Secure system decomposition and dependency design
• ../ops-devops-platform/SKILL.md — DevSecOps pipelines, secrets management, infrastructure hardening
• ../software-crypto-web3/SKILL.md — Smart contract security, blockchain vulnerabilities, DeFi patterns
• ../qa-testing-strategy/SKILL.md — Security testing, SAST/DAST integration, penetration testing

AI/LLM Security

• ../ai-llm/SKILL.md — LLM security patterns including prompt injection prevention
• ../ai-mlops/SKILL.md — ML model security, adversarial attacks, privacy-preserving ML

Quality & Resilience

• ../qa-resilience/SKILL.md — Resilience, safeguards, failure handling, chaos engineering
• ../qa-refactoring/SKILL.md — Security-focused refactoring patterns

Trend Awareness Protocol

IMPORTANT : When users ask recommendation questions about application security, you MUST use WebSearch to check current trends before answering. If WebSearch is unavailable, use data/sources.json + web browsing and state what you verified vs assumed.

Trigger Conditions

• "What's the best approach for [authentication/authorization]?"
• "What should I use for [secrets/encryption/API security]?"
• "What's the latest in application security?"
• "Current best practices for [OWASP/zero trust/supply chain]?"
• "Is [security approach] still recommended in 2026?"
• "What are the latest security vulnerabilities?"
• "Best auth solution for [use case]?"

Required Searches

1. Search: "application security best practices 2026"
2. Search: "OWASP Top 10 2025 2026"
3. Search: "[authentication/authorization] trends 2026"
4. Search: "supply chain security 2026"

What to Report

After searching, provide:

• Current landscape : What security approaches are standard NOW
• Emerging threats : New vulnerabilities or attack vectors
• Deprecated/declining : Approaches that are no longer secure
• Recommendation : Based on fresh data and current advisories

Example Topics (verify with fresh search)

• OWASP Top 10 updates
• Passkeys and passwordless authentication
• AI security concerns (prompt injection, model poisoning)
• Supply chain security (SBOMs, dependency scanning)
• Zero trust architecture implementation
• API security (BOLA, broken auth)

Pre-Implementation Security Gate

Before building any feature that involves storage, uploads, or user-generated content:

1. Threat model first : Identify what an attacker could do with this feature (file upload → malware, storage → data exfiltration, user content → XSS).
2. Check OWASP mapping : Map the feature to relevant OWASP Top 10 categories above.
3. Define constraints before coding : Set file type allowlist, size limits, storage isolation, and access controls before writing the first line.
4. Review existing security patterns : Check if the project already has upload/storage security utilities to reuse.

Building storage/upload features without upfront security constraints leads to retroactive hardening that is more expensive and error-prone.

Operational Playbooks

• references/operational-playbook.md — Core security principles, OWASP summaries, authentication patterns, and detailed code examples

Fact-Checking

• Use web search/web fetch to verify current external facts, versions, pricing, deadlines, regulations, or platform behavior before final answers.
• Prefer primary sources; report source links and dates for volatile information.
• If web access is unavailable, state the limitation and mark guidance as unverified.

Weekly Installs

97

Repository

vasilyu1983/ai-…s-public

GitHub Stars

49

First Seen

Jan 23, 2026

Security Audits

Gen Agent Trust HubPassSocketPassSnykWarn

Installed on

codex79

gemini-cli78

opencode78

cursor77

github-copilot73

amp65