security-audit

security-audit is a skill for Claude Code, Codex from cosmicstack-labs/mercury-agent-skills. It costs 41 tokens per session (4,203 once invoked), scanned B, original, MIT.

A structured guide to checking the security of applications, systems, and infrastructure for weaknesses.

In plain words
What is it for?
Use it to define audit scope, assess OWASP Top 10 risks, scan dependencies, model threats, investigate vulnerabilities, and write findings.
Why use it?
It helps make security reviews repeatable and ties each finding to evidence instead of assumptions.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to define audit scope, assess OWASP Top 10 risks, scan dependencies, model threats, investigate vulnerabilities, and write findings.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cosmicstack-labs/mercury-agent-skills/security-audit
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add cosmicstack-labs/mercury-agent-skills --skill security-audit
Clone the repo
git clone --depth 1 https://github.com/cosmicstack-labs/mercury-agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for security-audit

README.md
[![agentmods](https://agentmods.dev/badge/skills/cosmicstack-labs/mercury-agent-skills/security-audit/github.svg)](https://agentmods.dev/skills/cosmicstack-labs/mercury-agent-skills/security-audit)
Your own site
<a href="https://agentmods.dev/skills/cosmicstack-labs/mercury-agent-skills/security-audit"><img src="https://agentmods.dev/badge/skills/cosmicstack-labs/mercury-agent-skills/security-audit/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for security-audit

Your own site · 80×15
<a href="https://agentmods.dev/skills/cosmicstack-labs/mercury-agent-skills/security-audit"><img src="https://agentmods.dev/badge/skills/cosmicstack-labs/mercury-agent-skills/security-audit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 41 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,203 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Server-Side Request Forgery · line 107
    Code accesses a cloud instance metadata endpoint (e.g. 169.254.169.254). A single request can return temporary IAM credentials, making this a high-value SSRF target for credential theft.
    Fix: Remove access to cloud metadata endpoints unless strictly required. If metadata is needed, restrict it (e.g. IMDSv2 with hop limit) and never expose returned credentials.
  • high YARA Match · line 145
    YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).
    Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
  • medium MCP Rug Pull · line 221
    Docker image references without a specific tag (:latest is implicit) or digest (@sha256:...) can be silently replaced by a malicious image.
    Fix: Pin the image: image:tag or image@sha256:abc123
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00041 $0.04203
Opus 5 $0.00020 $0.02101
Sonnet 5 $0.00008 $0.00841
Haiku 4.5 $0.00004 $0.00420

Measured 8d ago against content hash 011777906709, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade B, and why

security-audit scanned grade B with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

- **Testing:** Point the application at internal services (`http://169.254.169.254/`, `http://localhost:9200/`).

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- **Testing:** Run scanners (Nuclei, Nikto), manual header inspection with curl/burp.
categories/security/security-audit/SKILL.md · 422 lines

How it starts

The opening of the file, as written. The whole thing — 422 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Audit Skill

A systematic approach to evaluating the security posture of applications, systems, and infrastructure. This skill equips you with the methodology, tooling, and reporting standards needed to conduct professional-grade security audits.


Core Principles

1. Defense in Depth

Security is not a single control but layered protections. An audit must evaluate each layer independently and in combination. A failure in one layer should be caught by another.

2. Least Privilege

Every component, user, and process should have the minimum permissions necessary to function. Audits must verify that privilege boundaries are enforced, not just declared.

3. Assume Breach

Design and audit with the assumption that an attacker has already compromised some part of the system. What can they access? What can they pivot to?

4. Repeatability

Audit procedures must be reproducible. If two auditors run the same methodology against the same target, they should reach consistent conclusions.

5. Evidence-Based Findings

Every finding must be backed by reproducible evidence — a screenshot, a log entry, a network capture, or a code path. "Trust me" is not a finding.

6. Continuous Improvement

A security audit is a snapshot in time. The goal is not just to find bugs but to improve the process so fewer bugs are introduced in the future.


Security Audit Maturity Model

Level Name Description
L0 Ad Hoc No formal audits. Security reviews happen reactively after incidents.
L1 Basic Manual vulnerability scanning with off-the-shelf tools. No standardized methodology or reporting.
L2 Defined Formal audit methodology documented. OWASP Top 10 covered. Findings tracked with CVSS scoring.
L3 Integrated Audits integrated into CI/CD pipeline. SAST/SCA runs on every commit. DAST runs on staging. Dedicated threat modeling sessions.
L4 Proactive Continuous security validation. Red team exercises. Bug bounty program. Attack surface management automated. Security metrics tracked over time.
L5 Adaptive Automated remediation for common findings. AI-assisted threat modeling. Self-healing security controls. Audit findings feed back into developer training.

Read the full file on GitHub · 422 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 422 lines · 41 tokens per session scan B 011777906709

Subscribe to this mod's changes

security-audit is a skill published in the GitHub repository cosmicstack-labs/mercury-agent-skills (471 stars, last pushed 17d ago), licensed MIT. It adds 41 tokens to every session and 4,203 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 2 findings (cloud metadata endpoint, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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