Categories

XSS Payload Detector

Detect XSS (Cross-Site Scripting) attack vectors in input strings

XSS Payload Detector

This tool helps identify potential XSS vulnerabilities in your input:

Detection Categories:

  • Script Tags: <script>, </script>, <script.*?>
  • Event Handlers: onclick, onload, onerror, onmouseover, etc.
  • Dangerous Protocols: javascript:, vbscript:, data:
  • iframe/frame: <iframe>, <frame>
  • Object/Embed: <object>, <embed>
  • Style Injection: <style>, expression(), -moz-binding
  • SVG-based XSS: <svg> tags with event handlers
  • DOM-based XSS: innerHTML, eval(), document.write()

Risk Levels:

  • LOW: Basic HTML tags without scripts
  • MEDIUM: Event handlers and protocols
  • HIGH: Script tags and encoded payloads
  • CRITICAL: Complete, executable XSS payloads

Example Attack Patterns:

  • <script>alert('XSS')</script>
  • <img src=x onerror=alert('XSS')>
  • <svg onload=alert('XSS')>
  • javascript:alert('XSS')
  • <iframe src="javascript:alert('XSS')">
  • %3Cscript%3Ealert('XSS')%3C/script%3E

Use Cases:

  • Validate user input before rendering
  • Scan log files for XSS attempts
  • Review code for potential vulnerabilities
  • Security testing and penetration testing
  • Educational tool for learning XSS attacks

Detect onclick, onload, onerror, and other event handlers

Detect <script> tags and related patterns

Detect javascript:, vbscript:, data: protocols

Detect URL-encoded and HTML entity-encoded attacks

Decode HTML entities and URL encoding before analysis

Maximum depth for nested pattern analysis

Key Facts

Category
Security
Input Types
textarea, checkbox, number
Output Type
json
Sample Coverage
4
API Ready
Yes

Overview

The XSS Payload Detector is a security tool that scans input strings for potential Cross-Site Scripting (XSS) attack vectors. It identifies dangerous patterns like script tags, event handlers, and encoded payloads to help prevent web vulnerabilities.

When to Use

  • When validating user-submitted content before rendering it on a web page to block XSS attacks.
  • When scanning server logs or user inputs for signs of malicious XSS attempts during security audits.
  • During penetration testing or code reviews to identify XSS flaws in web applications.

How It Works

  • Enter or paste the text to analyze into the input field.
  • Select which checks to perform, such as detecting script tags, event handlers, or dangerous protocols.
  • The tool matches the input against known XSS patterns and assigns risk levels based on severity.
  • Results are displayed in JSON format, detailing detected patterns, their positions, and risk ratings.

Use Cases

Testing user-generated content in forums or comment sections for XSS vulnerabilities before publication.
Forensic analysis of security logs to trace and decode XSS attack attempts in encoded formats.
Educational demonstrations to show how XSS attacks work and how to detect them in controlled environments.

Examples

1. Detecting Script Tag Injection in User Comments

Web Developer
Background
A developer is building a blog comment system and needs to ensure user comments do not contain malicious scripts.
Problem
Suspect that some comments might include <script> tags or event handlers like onclick.
How to Use
Paste the comment text into the tool, enable 'Check Script Tags' and 'Check Event Handlers', then run the analysis.
Outcome
The tool identifies a <script>alert('XSS')</script> pattern and flags it as HIGH risk, allowing the developer to sanitize the input.

2. Scanning Encoded XSS Payloads in Logs

Security Analyst
Background
An analyst is reviewing HTTP request logs that contain URL-encoded data from user inputs.
Problem
Need to decode and check for hidden XSS attacks in encoded strings like %3Cscript%3E.
How to Use
Input the encoded log entry, enable 'Check Encoded Payloads' and 'Decode and Analyze', then execute the scan.
Example Config
{"checkEncoded": true, "decodeEntities": true, "maxDepth": 5}
Outcome
The tool decodes %3Csvg%20onload%3Dalert('XSS')%3E and identifies it as a HIGH risk SVG-based XSS attempt.

Try with Samples

html, text

Related Hubs

FAQ

What is Cross-Site Scripting (XSS)?

XSS is a web security vulnerability where attackers inject malicious scripts into pages viewed by other users, potentially stealing data or performing unauthorized actions.

How does the tool detect XSS payloads?

It uses pattern matching to identify common XSS vectors like script tags, event handlers, and encoded strings, based on the selected analysis options.

Can I customize the detection checks?

Yes, you can enable or disable specific checks for event handlers, script tags, protocols, encoded payloads, and more using the provided options.

What risk levels does the tool assign?

Risk levels range from LOW for basic HTML tags to CRITICAL for complete, executable XSS payloads, helping prioritize security responses.

Is this tool suitable for real-time protection?

It's designed for testing and analysis. For real-time protection, integrate with web application firewalls or security libraries.

API Documentation

Request Endpoint

POST /en/api/tools/xss-payload-detector

Request Parameters

Parameter Name Type Required Description
text textarea Yes -
checkEventHandlers checkbox No Detect onclick, onload, onerror, and other event handlers
checkScriptTags checkbox No Detect