Agent skill

Owasp Security

by agamm in agamm/claude-code-owasp

Reviews code for security vulnerabilities and guides secure implementation using OWASP Top 10:2025, ASVS 5.0, the OWASP Top 10 for LLM Applications (2026), and the OWASP Top 10 for Agentic…

MITAuto-check passedSecurity

Install Owasp Security

skills CLI
$ npx skills add agamm/claude-code-owasp --skill owasp-security -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install agamm/claude-code-owasp owasp-security --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/agamm/claude-code-owasp.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/owasp-security .claude/skills/owasp-security && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
owasp-security
GitHub stars
377
Token cost
~3.5k tokens
SKILL.md length
1,669 words
Files
5
Skills in repo
1
Repo updated
First seen
Licence
MIT

At a glance

Reviews code for security vulnerabilities and guides secure implementation using OWASP Top 10:2025, ASVS 5.0, the OWASP Top 10 for LLM Applications (2026), and the OWASP Top 10 for Agentic…

  • Works in 4 steps: Is the input actually… → Is the sink reachable with that input?… → What is the blast radius? Who can… → …
  • A diff for security issues
  • SKILL.md covers Security Review Workflow, Before Reporting a Finding, Reporting Format and OWASP Top 10:2025, plus 3 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Owasp Security is an agent skill from agamm/claude-code-owasp. Reviews code for security vulnerabilities and guides secure implementation using OWASP Top 10:2025, ASVS 5.0, the OWASP Top 10 for LLM Applications (2026), and the OWASP Top 10 for Agentic Applications (2026). Use when reviewing code or a diff for security issues, implementing authentication, authorization, sessions, or cryptography, handling untrusted input, files, or URLs, hardening config, dependencies, or CI, or building LLM and AI agent features.

Its SKILL.md is about 3.5k tokens, which your agent loads only when the skill is triggered. The skill folder holds 5 other files (for example `reference/config-and-supply-chain.md`, `reference/languages.md` and `reference/owasp-report.md`).

It sits in Security, covering Web application vulnerabilities. The repository describes itself as: Claude Code skill for OWASP security best practices (2025-2026). Includes Top 10:2025, ASVS 5.0, Agentic AI security, and 20+ language-specific security quirks. The licence is MIT.

When your agent uses it

  • A diff for security issues
  • Implementing authentication
  • Handling untrusted input
  • Hardening config

Example prompts

  • “Use the owasp-security skill to review code for security vulnerabilities and guides secure implementation using OWASP Top 10:2025, ASVS 5.0, the…”
  • “/owasp-security”

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

  1. Is the input actually attacker-controlled? Trace it back to a real entry point: a
  2. Is the sink reachable with that input? Check whether validation, an allowlist, an ORM,
  3. What is the blast radius? Who can trigger it, what do they get, and does it cross a
  4. Can the attacker perform every step? Each step of the exploit must be possible from

What it can do on your machine

Read from SKILL.md and the folder at commit 8ac7965. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Owasp Security loads about 3.5k tokens when it runs. Until then it costs about 118 tokens; SKILL.md has 1,669 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~118
When it runs · the whole SKILL.md, loaded when a task matches
~3.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from agamm/claude-code-owasp at commit 8ac7965, republished under its MIT licence (© agamm). 1,669 words, ~3,509 tokens.

Download SKILL.mdSave it as .claude/skills/owasp-security/SKILL.md (or your agent's skills folder). This skill also uses 4 other files; get the full folder from GitHub.
name
owasp-security
description
Reviews code for security vulnerabilities and guides secure implementation using OWASP Top 10:2025, ASVS 5.0, the OWASP Top 10 for LLM Applications (2026), and the OWASP Top 10 for Agentic Applications (2026). Use when reviewing code or a diff for security issues, implementing authentication, authorization, sessions, or cryptography, handling untrusted input, files, or URLs, hardening config, dependencies, or CI, or building LLM and AI agent features.
when_to_use
Trigger phrases include "security review", "security check", "anything exploitable", "audit this", "is this secure", "is this safe to ship", "check for…

OWASP Security

Apply these standards when writing or reviewing code. For a review, follow the workflow below.

Reference files (read the one the task needs, and only the section you need):

  • reference/review-checklist.md: coverage checklist for every Top 10 category, plus LLM and agent checks. Read during step 3 of a review.
  • reference/languages.md: per-language pitfalls with unsafe/safe examples for 20+ languages. Read the section for the language under review.
  • reference/config-and-supply-chain.md: A02 and A03 in Dockerfiles, Kubernetes, Terraform, framework config, security headers, lockfiles, and CI/CD. Read when the change touches config, IaC, dependencies, or pipelines.
  • reference/owasp-report.md: attack vectors, mitigations, and worked examples for every Top 10:2025, ASVS 5.0, LLM Top 10, and Agentic item. About 1100 lines: jump to the section you need.

Security Review Workflow

Copy this checklist into your response and tick it off as you go:

Security Review Progress:
- [ ] Step 1: Map entry points and trust boundaries
- [ ] Step 2: Load the references this code needs
- [ ] Step 3: Sweep for candidate issues
- [ ] Step 4: Triage every candidate
- [ ] Step 5: Report findings

Step 1: Map entry points and trust boundaries. List where attacker-controlled data enters: routes and handlers, headers and cookies, uploads, webhooks, queue consumers, CLI arguments, third-party API responses, and anything an LLM reads or returns. Note where authentication and authorization are enforced; it is often centralized in middleware rather than per route.

Step 2: Load the references this code needs. The language section of languages.md; config-and-supply-chain.md if config, IaC, dependencies, or CI changed; the LLM and Agentic sections of owasp-report.md if the code calls a model or runs an agent.

Step 3: Sweep for candidate issues. Walk review-checklist.md for the categories the code touches. For each candidate, trace the path from an entry point in step 1 to the sink.

Step 4: Triage every candidate with the rubric in "Before Reporting a Finding" below. Drop candidates that fail it, or downgrade them to defense-in-depth. If a candidate's reachability is unclear, go back to step 1 for that input before deciding.

Step 5: Report findings in the format below, highest severity first.

Before Reporting a Finding

A pattern match is not a vulnerability. The most common failure mode in automated security review is reporting unreachable or already-mitigated code, which buries the real findings. Confirm all four before reporting:

  1. Is the input actually attacker-controlled? Trace it back to a real entry point: a request parameter, header, cookie, uploaded file, webhook, queue message, or third-party API response. A value that only ever comes from a constant, an enum, or trusted internal config is not an injection source.
  2. Is the sink reachable with that input? Check whether validation, an allowlist, an ORM, or a framework-level control already sits between them. Look for auth middleware (middleware.ts, proxy.ts, Express/Django/Rails middleware, a base controller, decorators) before flagging a route as missing authorization. Enforcement is often centralized rather than per-route.
  3. What is the blast radius? Who can trigger it, what do they get, and does it cross a trust boundary? An SSRF reaching cloud metadata differs from one reaching localhost only.
  4. Can the attacker perform every step? Each step of the exploit must be possible from the attacker's position. A symlink race needs a way to create symlinks on the server; a header attack needs a client that can set that header. If a step needs a capability the code doesn't show the attacker having, the finding is "Needs verification", not High.

Report severity by exploitability, not by pattern. State the concrete path (this input reaches this sink) and say so explicitly when a finding is theoretical or defense-in-depth rather than directly exploitable. If reachability can't be determined from the code available, say that instead of asserting either way.

Reporting Format

One block per finding, highest severity first:

[SEVERITY] Title (CWE-###, OWASP A##:2025, LLM## Risk Name, ASI## Risk Name)
Location:   path/to/file.ext:LINE
Path:       <entry point> -> <intermediate hops> -> <sink>
Impact:     who can trigger it, what they get, which trust boundary it crosses
Fix:        the concrete change, with a code snippet when it isn't obvious
Confidence: Confirmed | Likely | Needs verification (say what you couldn't see)

Write every LLM and ASI ID with its risk name, e.g. "LLM03 Excessive Agency". A bare LLM ID is ambiguous: the 2025 and 2026 editions use the same numbers for different risks.

SeverityMeaning
CriticalUnauthenticated remote code execution, auth bypass, or mass data exposure
HighAuthenticated exploitation crossing a trust boundary (IDOR into other tenants, SQLi behind login)
MediumNeeds unusual preconditions, or impact is limited to the attacker's own data
LowDefense-in-depth gap with no demonstrated exploit path
InfoHardening suggestion; say plainly that it is not a vulnerability

If the review finds nothing exploitable, say so directly. Do not pad the report with Info items to look thorough; a long list is what makes real findings get ignored.

OWASP Top 10:2025

Three categories were renamed from 2021 and two are new (A03, A10). Use these names and numbers; much OWASP material online still cites the 2021 list.

#CategoryKey Prevention
A01Broken Access Control (now includes SSRF)Deny by default, enforce server-side, verify ownership
A02Security MisconfigurationHarden configs, disable defaults, minimize features
A03Software Supply Chain FailuresLock versions, verify integrity, audit dependencies
A04Cryptographic FailuresTLS 1.2+, AES-256-GCM, Argon2/bcrypt for passwords
A05InjectionParameterized queries, input validation, safe APIs
A06Insecure DesignThreat model, rate limit, design security controls
A07Authentication FailuresMFA, check breached passwords, secure sessions
A08Software or Data Integrity FailuresSign packages, SRI for CDN, safe serialization
A09Security Logging and Alerting FailuresLog security events, structured format, alerting
A10Mishandling of Exceptional ConditionsFail-closed, hide internals, log with context

OWASP Top 10 for LLM Applications (2026)

For applications that call LLMs (chatbots, RAG, copilots, agents). The 2026 edition renumbered the list; translate 2025 IDs with the table in owasp-report.md and cite 2026 IDs only.

#RiskKey Mitigation
LLM01Prompt InjectionNo complete fix exists. Fence untrusted content (including images, audio, tool output), keep privileges out of the model's reach, filter outputs
LLM02Sensitive Information DisclosureSanitize training/RAG data, strip PII from context, restrict what the model can retrieve per user
LLM03Excessive AgencyMinimize tools and permissions, require human approval for destructive actions, scope credentials per task
LLM04Supply ChainVerify model provenance and signatures, vet third-party model hubs, lock model + adapter versions
LLM05Data and Model PoisoningValidate training/fine-tuning sources, anomaly-detect on data ingestion, hold-out integrity tests
LLM06Unbounded ConsumptionRate-limit per user/key, cap tokens and tool calls per request, monitor cost, set hard timeouts
LLM07MisinformationCite sources, surface confidence, require grounding for high-stakes answers, disclose AI provenance
LLM08Hidden Context ExposureAssume the system prompt, tool schemas, and other hidden context are extractable: no secrets there, and no authorization or policy that relies on them staying hidden
LLM09Vector and Embedding WeaknessesTenant-isolate vector stores, access-control on retrieval, sign or hash chunks against indirect prompt injection
LLM10Improper Output HandlingTreat all LLM output, including generated code, as untrusted input: validate, escape, or sandbox before any sink (SQL, shell, HTML, code, tool calls)
Show full SKILL.md (582 more words)Show less

OWASP Top 10 for Agentic Applications (2026)

For AI agent systems that plan, call tools, or keep memory:

RiskDescriptionMitigation
ASI01: Agent Goal HijackPrompt injection alters agent objectivesTreat tool and retrieved content as data, goal boundaries, behavioral monitoring
ASI02: Tool Misuse & ExploitationTools used in unintended waysLeast privilege, fine-grained permissions, validate I/O
ASI03: Identity & Privilege AbuseDelegated trust, inherited credentials, role chain exploitsShort-lived scoped tokens, identity verification
ASI04: Agentic Supply Chain VulnerabilitiesCompromised plugins/MCP serversVerify signatures, sandbox, allowlist plugins
ASI05: Unexpected Code ExecutionUnsafe code generation/executionSandbox execution, static analysis, human approval
ASI06: Memory & Context PoisoningCorrupted RAG/context dataValidate stored content, segment by trust level
ASI07: Insecure Inter-Agent CommunicationSpoofing/intercepting agent-to-agent messagesAuthenticate, encrypt, verify message integrity
ASI08: Cascading FailuresErrors propagate across systemsCircuit breakers, graceful degradation, isolation
ASI09: Human-Agent Trust ExploitationOver-trust in agents leveraged to manipulate usersLabel AI content, user education, verification steps
ASI10: Rogue AgentsCompromised agents acting maliciouslyBehavior monitoring, kill switches, anomaly detection

ASVS 5.0 Key Requirements

ASVS 5.0 (May 2025) renumbered and reorganized every chapter. 4.0 requirement IDs do not map to 5.0 — V2.1.1 meant "password length" in 4.0 and means something else now. Cite 5.0 IDs only. Levels are defined by share of requirements, not by application category:

LevelShareIntent
L1~20%Minimum bar; deliberately small to lower the barrier to entry
L2~50% (≈70% cumulative)What most applications should target
L3remaining ~30%Highest assurance
Level 1 — the minimum bar
  • Passwords at least 8 characters; 15+ strongly recommended (6.2.1)
  • No composition rules — permit any characters, paste, and password managers (6.2.5, 6.2.7)
  • Block at least the top 3000 common passwords (6.2.4)
  • Anti-automation against credential stuffing and brute force (6.3.1)
  • No default accounts like root/admin/sa (6.3.2)
  • Reference session tokens from a CSPRNG with 128+ bits entropy (7.2.3)
  • New session token issued on authentication and re-authentication (7.2.4)
  • Session fully unusable after logout or expiry (7.4.1)
  • Function-level and data-level access restricted to explicit permissions (8.2.1, 8.2.2)
  • Authorization enforced at a trusted service layer the client cannot manipulate (8.3.1)
  • Parameterized queries / ORM for all data access (1.2.4); parameterized OS calls (1.2.5)
  • Context-appropriate output encoding for HTML, URLs, and JavaScript/JSON (1.2.1–1.2.3)
  • Avoid eval() and dynamic code execution (1.3.2)
  • Input validated at a trusted service layer, positive/allowlist where possible (2.2.1, 2.2.2)
  • TLS 1.2+ on all external traffic, publicly trusted certificates (12.1.1, 12.2.1, 12.2.2)
  • Approved ciphers and modes only — no ECB, no PKCS#1 v1.5 padding (11.3.1, 11.3.2)
  • No sensitive data in URLs or query strings (14.2.1)
Level 2 — what most applications should target
  • MFA, or a documented combination of single factors (6.3.3)
  • Passwords checked against a breached-password set (6.2.12)
  • No forced periodic password rotation — rotate only on compromise (6.2.10)
  • All security logging starts here. ASVS 5.0 has no L1 logging requirements; the whole of V16 is L2+. Log authentication attempts, failed authorization, security events, and unexpected errors (16.3.1–16.3.4)
  • Log entries carry when/where/who/what metadata on a synchronized clock (16.2.1, 16.2.2)
  • Logs encoded against log injection, protected from modification, shipped off-box (16.4.1–16.4.3)
  • Generic error message to the user; detail stays in the log (16.5.1)
Level 3 — highest assurance

ASVS 5.0 has 92 L3 requirements; they are not enumerated here. Two worth knowing because they tighten an L2 requirement rather than adding a new one:

  • One factor must be hardware-based and phishing-resistant, e.g. a FIDO key (6.3.3, L3 clause)
  • Log all authorization decisions, not only failures (16.3.2, L3 clause)

For an actual L3 assessment, work from the standard itself — see reference/owasp-report.md for the chapter map.

© agamm, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files in .claude/skills/owasp-security of agamm/claude-code-owasp.

  • SKILL.md
  • reference/config-and-supply-chain.md
  • reference/languages.md
  • reference/owasp-report.md
  • reference/review-checklist.md

Open the folder on GitHubat commit 8ac7965

Compare with similar skills

Owasp Security next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Owasp Security compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Owasp Security this skillagamm/claude-code-owasp377—~3.5kAutomated safety check: PassMIT
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Security Auditoreigent-ai/eigent15k—~1.8kAutomated safety check: NotesApache-2.0
Security Reviewjewbetcha/opentrace11618 repos~3.1kAutomated safety check: NotesMIT
Strix Code Vulnerability Scanusestrix/strix67k—~1.1kAutomated safety check: PassApache-2.0
Code Audit3stoneBrother/code-audit8931 repos~2.7kAutomated safety check: PassNone

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Categories

Questions about Owasp Security

What does Owasp Security do?

Reviews code for security vulnerabilities and guides secure implementation using OWASP Top 10:2025, ASVS 5.0, the OWASP Top 10 for LLM Applications (2026), and the OWASP Top 10 for Agentic…. Owasp Security is an agent skill from agamm/claude-code-owasp.0, the OWASP Top 10 for LLM Applications (2026), and the OWASP Top 10 for Agentic Applications (2026).

When should I use Owasp Security?

Owasp Security fits situations like: A diff for security issues; implementing authentication; handling untrusted input; hardening config.

How do I install Owasp Security in Claude Code?

Run `npx skills add agamm/claude-code-owasp --skill owasp-security -a claude-code`. Or copy the skill folder (.claude/skills/owasp-security in agamm/claude-code-owasp) into .claude/skills/owasp-security in your project. Claude Code loads it when a task matches its description.

How do I install Owasp Security in Codex?

Run `npx skills add agamm/claude-code-owasp --skill owasp-security -a codex`. Or copy the skill folder (.claude/skills/owasp-security in agamm/claude-code-owasp) into .agents/skills/owasp-security in your project. Codex loads it when a task matches its description.

Can I use Owasp Security in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add agamm/claude-code-owasp --skill owasp-security -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/owasp-security, .gemini/skills/owasp-security, .github/skills/owasp-security and .opencode/skills/owasp-security in your project.

What does Owasp Security need to run?

SKILL.md names no scripts, command-line tools or credentials: Owasp Security is instructions for the agent only.

Does Owasp Security access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Owasp Security safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Owasp Security use?

Owasp Security is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Owasp Security use?

About 3.5k tokens (SKILL.md is roughly 14k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Owasp Security?

Skills that share tags, products or a category with Owasp Security: Security And Hardening (penpot/penpot, 61k stars), Security Auditor (eigent-ai/eigent, 15k stars), Security Review (jewbetcha/opentrace, 116 stars) and Strix Code Vulnerability Scan (usestrix/strix, 67k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Owasp Security?

agamm (a GitHub user) maintains it in agamm/claude-code-owasp, which has 377 GitHub stars. The repository was last updated on September 25, 2026.

Source: agamm/claude-code-owasp on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.