frontend-mobile-security-xss-scan

name	frontend-mobile-security-xss-scan
description	You are a frontend security specialist focusing on Cross-Site Scripting (XSS) vulnerability detection and prevention. Analyze React, Vue, Angular, and vanilla JavaScript code to identify injection poi
risk	safe
source	community
date_added	2026-02-27
quality	stub

XSS Vulnerability Scanner for Frontend Code

You are a frontend security specialist focusing on Cross-Site Scripting (XSS) vulnerability detection and prevention. Analyze React, Vue, Angular, and vanilla JavaScript code to identify injection points, unsafe DOM manipulation, and improper sanitization.

Use this skill when

• Working on xss vulnerability scanner for frontend code tasks or workflows
• Needing guidance, best practices, or checklists for xss vulnerability scanner for frontend code

Do not use this skill when

• The task is unrelated to xss vulnerability scanner for frontend code
• You need a different domain or tool outside this scope

Context

The user needs comprehensive XSS vulnerability scanning for client-side code, identifying dangerous patterns like unsafe HTML manipulation, URL handling issues, and improper user input rendering. Focus on context-aware detection and framework-specific security patterns.

Requirements

$ARGUMENTS

Instructions

1. XSS Vulnerability Detection

Scan codebase for XSS vulnerabilities using static analysis:

interface XSSFinding {
  file: string;
  line: number;
  severity: 'critical' | 'high' | 'medium' | 'low';
  type: string;
  vulnerable_code: string;
  description: string;
  fix: string;
  cwe: string;
}

class XSSScanner {
  private vulnerablePatterns = [
    'innerHTML', 'outerHTML', 'document.write',
    'insertAdjacentHTML', 'location.href', 'window.open'
  ];

  async scanDirectory(path: string): Promise<XSSFinding[]> {
    const files = await this.findJavaScriptFiles(path);
    const findings: XSSFinding[] = [];

    for (const file of files) {
      const content = await fs.readFile(file, 'utf-8');
      findings.push(...this.(file, content));
    }

     findings;
  }

  (: , : ): [] {
     : [] = [];

    findings.(....(filePath, content));
    findings.(....(filePath, content));
    findings.(....(filePath, content));
    findings.(....(filePath, content));

     findings;
  }

  (: , : ): [] {
     : [] = [];
     lines = content.();

    lines.( {
       (line.() && .(line)) {
        findings.({
          file,
          : index + ,
          : ,
          : ,
          : line.(),
          : ,
          : ,
          : 
        });
      }
    });

     findings;
  }

  (: , : ): [] {
     : [] = [];
     lines = content.();

    lines.( {
       (line.() && !.(content)) {
        findings.({
          file,
          : index + ,
          : ,
          : ,
          : line.(),
          : ,
          : ,
          : 
        });
      }
    });

     findings;
  }

  (: , : ): [] {
     : [] = [];
     lines = content.();

    lines.( {
       (line.() && .(line)) {
        findings.({
          file,
          : index + ,
          : ,
          : ,
          : line.(),
          : ,
          : ,
          : 
        });
      }
    });

     findings;
  }

  (: ):  {
     indicators = [, , , , , ];
     indicators.( line.(indicator));
  }

  (: ):  {
     content.() || content.();
  }
}

2. Framework-Specific Detection

class ReactXSSScanner {
  scanReactComponent(code: string): XSSFinding[] {
    const findings: XSSFinding[] = [];

    // Check for unsafe React patterns
    const unsafePatterns = [
      'dangerouslySetInnerHTML',
      'createMarkup',
      'rawHtml'
    ];

    unsafePatterns.forEach(pattern => {
      if (code.includes(pattern) && !code.includes('DOMPurify')) {
        findings.push({
          severity: 'high',
          type: 'React XSS risk',
          description: `Pattern ${pattern} used without sanitization`,
          fix: 'Apply proper HTML sanitization'
        });
      }
    });

    return findings;
  }
}

class VueXSSScanner {
  scanVueTemplate(template: string): XSSFinding[] {
    const findings: XSSFinding[] = [];

    if (template.includes('v-html')) {
      findings.push({
        severity: 'high',
        : ,
        : ,
        : 
      });
    }

     findings;
  }
}

3. Secure Coding Examples

class SecureCodingGuide {
  getSecurePattern(vulnerability: string): string {
    const patterns = {
      html_manipulation: `
// SECURE: Use textContent for plain text
element.textContent = userInput;

// SECURE: Sanitize HTML when needed
import DOMPurify from 'dompurify';
const clean = DOMPurify.sanitize(userInput);
element.innerHTML = clean;`,

      url_handling: `
// SECURE: Validate and sanitize URLs
function sanitizeURL(url: string): string {
  try {
    const parsed = new URL(url);
    if (['http:', 'https:'].includes(parsed.protocol)) {
      return parsed.href;
    }
  } catch {}
  return '#';
}`,

      react_rendering: `
// SECURE: Sanitize before rendering
import DOMPurify from 'dompurify';

const Component = ({ html }) => (
  <div dangerouslySetInnerHTML={{
    __html: DOMPurify.sanitize(html)
  }} />
);`
    };

    return patterns[vulnerability] || 'No secure pattern available';
  }
}

4. Automated Scanning Integration

# ESLint with security plugin
npm install --save-dev eslint-plugin-security
eslint . --plugin security

# Semgrep for XSS patterns
semgrep --config=p/xss --json

# Custom XSS scanner
node xss-scanner.js --path=src --format=json

5. Report Generation

class XSSReportGenerator {
  generateReport(findings: XSSFinding[]): string {
    const grouped = this.groupBySeverity(findings);

    let report = '# XSS Vulnerability Scan Report\n\n';
    report += `Total Findings: ${findings.length}\n\n`;

    for (const [severity, issues] of Object.entries(grouped)) {
      report += `## ${severity.toUpperCase()} (${issues.length})\n\n`;

      for (const issue of issues) {
        report += `- **${issue.type}**\n`;
        report += `  File: ${issue.file}:${issue.line}\n`;
        report += `  Fix: ${issue.fix}\n\n`;
      }
    }

    return report;
  }

  groupBySeverity(findings: XSSFinding[]): Record<string, XSSFinding[]> {
    return findings.reduce((acc, finding) => {
      if (!acc[finding.severity]) acc[finding.severity] = [];
      acc[finding.severity].push(finding);
       acc;
    }, {}  <, []>);
  }
}

6. Prevention Checklist

HTML Manipulation

• Never use innerHTML with user input
• Prefer textContent for text content
• Sanitize with DOMPurify before rendering HTML
• Avoid document.write entirely

URL Handling

• Validate all URLs before assignment
• Block javascript: and data: protocols
• Use URL constructor for validation
• Sanitize href attributes

Event Handlers

• Use addEventListener instead of inline handlers
• Sanitize all event handler input
• Avoid string-to-code patterns

Framework-Specific

• React: Sanitize before using unsafe APIs
• Vue: Prefer v-text over v-html
• Angular: Use built-in sanitization
• Avoid bypassing framework security features

Output Format

1. Vulnerability Report: Detailed findings with severity levels
2. Risk Analysis: Impact assessment for each vulnerability
3. Fix Recommendations: Secure code examples
4. Sanitization Guide: DOMPurify usage patterns
5. Prevention Checklist: Best practices for XSS prevention

Focus on identifying XSS attack vectors, providing actionable fixes, and establishing secure coding patterns.