Self Cross Site Scripting

The tester discovered that the URL parameter is susceptible to XSS payload injection. Upon clicking the button, the injected script is executed.

Step by Step

1. Insert payload to URL “javascript:alert(/xss/)”, “javascript:alert(document.domain)”.
2. Click the button.
3. The JavaScript payload was executed as expected.

Solution

Self-XSS (Cross-Site Scripting) typically involves a user inadvertently executing malicious code within their own context, often through social engineering techniques. This can occur when a user is tricked into pasting and executing malicious JavaScript code into the browser's developer console or address bar.

Mitigating self-XSS vulnerabilities involves a combination of user education, proper security measures, and platform-specific defenses. Here are some strategies to mitigate self-XSS:

1. Content Security Policy (CSP): Implement a Content Security Policy that restricts the execution of inline JavaScript and limits the sources from which scripts can be loaded. CSP can help prevent the execution of injected scripts, including those entered through the address bar or developer console.
2. Input Sanitization: Validate and sanitize user input on the server-side to prevent the insertion of malicious scripts into the application's data. Use strict input validation and sanitize user-generated content before rendering it in the browser.
3. Client-Side Input Validation: Implement client-side input validation and filtering to prevent users from submitting potentially harmful content. However, keep in mind that client-side validation alone is not sufficient and can be bypassed by determined attackers.
4. Developer Console Warnings: Display warnings in the developer console or browser's console when users attempt to execute code that may be malicious or could compromise their account security. This can help raise awareness and prompt users to exercise caution.
5. Rate Limiting: Implement rate limiting or restrictions on the frequency and volume of requests made by users to help detect and mitigate automated attacks or attempts to exploit self-XSS vulnerabilities.
6. Reporting Mechanisms: Provide users with mechanisms to report suspicious activities or content, including potential instances of self-XSS. Promptly investigate and address reports to prevent further exploitation.
7. Session Management: Implement secure session management practices, including the use of secure cookies, session timeouts, and mechanisms to detect and prevent session hijacking attacks.