Unsanitized user input in raw HTML strings (XSS)

Description

Including unsanitized user input in HTML exposes your application to cross-site scripting (XSS) attacks. This vulnerability allows attackers to inject malicious scripts into web pages viewed by other users.

Remediations

  • Do not include user input directly in HTML strings. This practice can lead to XSS vulnerabilities.
    html = f"<h1>{user_input}</h1>" # unsafe
  • Do use a framework or templating language that automatically handles the encoding and sanitization of user input when constructing HTML. This approach minimizes the risk of XSS attacks.
  • Do sanitize user input if you must use HTML strings directly. Utilize libraries designed for input sanitization to ensure that user input does not contain malicious content.
    from html_sanitizer import Sanitizer

    sanitizer = Sanitizer()
    sanitized_value = sanitizer.sanitize(user_input)
    html = f"<h1>{sanitized_value}</h1>"

References

Associated CWE

OWASP Top 10

Configuration

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

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

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

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