Objective: To manipulate the content or behavior of an AMP page, leading to user misinformation, redirection to malicious sites, or exfiltration of limited user data, all while bypassing AMP's validation and security mechanisms.
[Attacker's Goal: Manipulate AMP Page Content/Behavior] | {2. Exploit AMP Component Vulnerabilities} | {2.1 XSS via Vulnerable Component (e.g., amp-bind)} | --------------------- | | {2.1.1 Bypass <<2.1.2 Inject Sanitization} Malicious Code>>
Attack Tree Path: High-Risk Path: {2. Exploit AMP Component Vulnerabilities -> 2.1 XSS via Vulnerable Component -> 2.1.1 Bypass Sanitization}
Overall Description: This path represents the attacker's attempt to achieve Cross-Site Scripting (XSS) by exploiting a vulnerability in an AMP component, specifically focusing on components that handle dynamic content or user input (like amp-bind). The attacker aims to bypass the component's built-in sanitization mechanisms to inject malicious code.
Step 2: Exploit AMP Component Vulnerabilities:
Description: The attacker identifies an AMP component that is used on the target page and is potentially vulnerable to XSS. This could be due to a known vulnerability, a misconfiguration, or a newly discovered (zero-day) vulnerability. The attacker researches the component's functionality and input handling.
Example: The attacker targets amp-bind because it allows for dynamic data binding and expression evaluation, which can be complex and prone to vulnerabilities if not handled carefully. Other potential targets include components that handle user input, such as amp-form (though XSS is less direct there), or components that render external content, like amp-list (if fetching data from a compromised source).
Mitigation Strategies:
Use only necessary AMP components.
Regularly update all AMP components to the latest versions.
Thoroughly review the security documentation for each component used.
Implement a robust testing process, including security testing and fuzzing, specifically targeting the components used.
Step 2.1: XSS via Vulnerable Component (e.g., amp-bind):
Description: The attacker focuses on a specific component (e.g., amp-bind) and crafts input that is designed to trigger an XSS vulnerability. This often involves manipulating data that is used within amp-bind expressions.
Example: If a website uses amp-bind to display a user's name, and the name is not properly sanitized, the attacker might try to inject a name like <script>alert('XSS')</script>. If the sanitization fails, this script could be executed.
Mitigation Strategies:
Avoid using user-supplied data directly in amp-bind expressions without proper escaping and validation.
Use a whitelist approach to allow only specific, safe expressions.
Implement strict input validation and sanitization on any data that is used within amp-bind expressions, even if it appears to be coming from a trusted source.
Use a linter that specifically checks for potential amp-bind vulnerabilities.
Step 2.1.1: Bypass Sanitization:
Description: The attacker attempts to circumvent the component's built-in sanitization mechanisms. This might involve using obscure HTML entities, exploiting browser quirks, or finding flaws in the sanitization logic itself.
Example: The attacker might try to use HTML entities like < instead of < to bypass a simple filter that only looks for the literal < character. Or, they might try to use nested expressions or JavaScript events that are not properly handled by the sanitization routine.
Mitigation Strategies:
Use well-established and thoroughly tested sanitization libraries.
Regularly review and update the sanitization logic.
Perform penetration testing to identify potential bypasses.
Employ a Content Security Policy (CSP) as an additional layer of defense, even on AMP pages.
Attack Tree Path: Critical Node: <<2.1.2 Inject Malicious Code>>
Description: This is the pivotal point where the attacker successfully injects and executes malicious JavaScript code within the context of the AMP page. This means the attacker has bypassed all preceding security measures. Impact: Once malicious code is executed, the attacker can: Steal user cookies and session tokens, leading to account takeover. Redirect the user to a phishing site or a site that delivers malware. Deface the website by modifying its content. Exfiltrate sensitive data displayed on the page. Perform actions on behalf of the user (e.g., making posts, sending messages). Mitigation Strategies: All mitigation strategies listed above for the preceding steps are crucial to prevent this node from being reached. The focus should be on preventing the injection in the first place, through robust input validation, sanitization, and secure component usage.