Usage of manual HTML sanitization (XSS)

• Rule ID: javascript_lang_manual_html_sanitization
• Languages: javascript
• Source: manual_html_sanitization.yml

Description

Sanitizing HTML manually is error prone and can lead to Cross Site Scripting (XSS) vulnerabilities.

Remediations

❌ Avoid manually escaping HTML:

const sanitizedUserInput = user.Input
  .replaceAll('<', '&lt;')
  .replaceAll('>', '&gt;');
const html = `<strong>${sanitizedUserInput}</strong>`;

✅ Use a HTML sanitization library:

import sanitizeHtml from 'sanitize-html';

const html = sanitizeHtml(`<strong>${user.Input}</strong>`);

Resources

• OWASP XSS explained

Associated CWE

• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

OWASP Top 10

• A03:2021 - Injection

Configuration

To skip this rule during a scan, use the following flag

bearer scan /path/to/your-project/ --skip-rule=javascript_lang_manual_html_sanitization

To run only this rule during a scan, use the following flag

bearer scan /path/to/your-project/ --only-rule=javascript_lang_manual_html_sanitization