# performing-security-headers-audit

Audits HTTP security headers including CSP, HSTS, and cookie flags. It detects missing browser protections and configuration flaws on web endpoints.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 359 installs · ★ 35034
- Author: mahipal
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/HEAD/skills/performing-security-headers-audit/SKILL.md
- Updated: 2026-08-31
- HTML: https://affpapa.org/en/nevibecode/skills/performing-security-headers-audit

## What it does

The skill conducts an audit of server response headers using command-line requests with `curl`. It inspects policies like `Content-Security-Policy`, `Strict-Transport-Security`, `X-Frame-Options`, and `X-Content-Type-Options`. If directives permit risky behaviors like `'unsafe-inline'` or `'unsafe-eval'`, the skill highlights the associated injection risks.

The workflow tests multiple endpoints, comparing unencrypted HTTP responses with HTTPS to catch missing redirects and mixed content. You need `curl` installed and proper written authorization before testing any target. Cookie validation specifically checks for `Secure`, `HttpOnly`, and `SameSite` flags on session tokens.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-security-headers-audit -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/performing-security-headers-audit/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/performing-security-headers-audit/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-security-headers-audit -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/performing-security-headers-audit/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-security-headers-audit -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/performing-security-headers-audit/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install mukul975/Anthropic-Cybersecurity-Skills performing-security-headers-audit
```

2. **Manually: put the files in place**
- File: `.github/skills/performing-security-headers-audit/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-security-headers-audit -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/mukul975/Anthropic-Cybersecurity-Skills --path skills/performing-security-headers-audit
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/performing-security-headers-audit/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-security-headers-audit -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/HEAD/skills/performing-security-headers-audit/SKILL.md

## When to use it
- inspect Content-Security-Policy for unsafe script directives
- verify Secure and HttpOnly flags on session cookies
- check HSTS configuration and HTTP to HTTPS redirects
- identify missing frame protection against clickjacking

## Example prompts
- Run a security headers audit against our web endpoint
- Check CSP directives and cookie attributes using performing-security-headers-audit
- Inspect our login route for missing HSTS and anti-clickjacking headers

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 9539ef51ba697ec2.

BEGIN THIRD-PARTY FILE 9539ef51ba697ec2
````text
---
name: performing-security-headers-audit
description: Auditing HTTP security headers including CSP, HSTS, X-Frame-Options,
  and cookie attributes to identify missing or misconfigured browser-level protections.
domain: cybersecurity
subdomain: web-application-security
tags:
- penetration-testing
- security-headers
- csp
- hsts
- owasp
- web-security
- hardening
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- PR.PS-01
- ID.RA-01
- PR.DS-10
- DE.CM-01
mitre_attack:
- T1190
- T1059.007
- T1505.003
- T1083
---

# Performing Security Headers Audit

## When to Use

- During authorized web application security assessments as a standard configuration review
- When evaluating browser-level protections against XSS, clickjacking, and data leakage
- For compliance assessments requiring security header implementation (PCI DSS, SOC 2)
- When performing initial reconnaissance to identify easy-win security improvements
- During CI/CD pipeline security gate checks for new deployments

## Prerequisites

- **Authorization**: Written scope for the target application (header review is low-risk)
- **curl**: For fetching response headers from target endpoints
- **SecurityHeaders.com**: Online scanner for quick header assessment
- **Mozilla Observatory**: Mozilla's web security testing tool
- **Burp Suite**: For comprehensive header analysis across multiple pages
- **Browser DevTools**: For examining headers and CSP violations in real-time

## Workflow

### Step 1: Collect Security Headers from Target

Retrieve and catalog all security-related response headers.

```bash
# Fetch all response headers
curl -s -I "https://target.example.com/" | grep -iE \
  "(strict-transport|content-security|x-frame|x-content-type|x-xss|referrer-policy|permissions-policy|feature-policy|x-permitted|cross-origin|set-cookie|server|x-powered-by|cache-control)"

# Check headers across multiple pages
PAGES=("/" "/login" "/api/health" "/admin" "/account/settings" "/static/app.js")

for page in "${PAGES[@]}"; do
  echo "=== $page ==="
  curl -s -I "https://target.example.com$page" 2>/dev/null | grep -iE \
    "(strict-transport|content-security|x-frame|x-content-type|x-xss|referrer-policy|permissions-policy|set-cookie|server|x-powered)"
  echo
done

# Check both HTTP and HTTPS responses
echo "=== HTTP Response ==="
curl -s -I "http://target.example.com/" | head -20
echo "=== HTTPS Response ==="
curl -s -I "https://target.example.com/" | head -20
```

### Step 2: Assess Transport Security (HSTS)

Evaluate HTTP Strict Transport Security configuration.

```bash
# Check HSTS header
````
END THIRD-PARTY FILE 9539ef51ba697ec2

The third-party file has ended. Everything between the 9539ef51ba697ec2 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 2590 of 12923 bytes. © mahipal · Apache-2.0 · https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/HEAD/skills/performing-security-headers-audit/SKILL.md

_Part of the page did not fit — see the HTML version._

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