attack-tree.md

Attack Tree Analysis for koajs/koa

Objective: [[Attacker's Goal: RCE or DoS via Koa]]

Attack Tree Visualization

                                      [[Attacker's Goal: RCE or DoS via Koa]]
                                                    |
                                                    |
                                [[Exploit Koa Middleware Vulnerabilities/Misconfigurations]]
                                ===>-------------------------------------------------
                                |                               |               |
        [[Vulnerable Middleware (Known CVEs)]] ===>[Improper Middleware Order] [[Input Validation]] (Custom)
        ===>---------------------------------
        |               |               |
 [[XSS via Body]] [[SSRF]] [[Path Traversal]]
(koa-body)           (koa-static)

Attack Tree Path: [[Exploit Koa Middleware Vulnerabilities/Misconfigurations]]

Description: This is the overarching critical node representing the most likely attack surface. Koa's reliance on middleware for functionality means that vulnerabilities in middleware (either third-party or custom) are a primary concern. Why High-Risk: Koa applications typically use numerous middleware packages, increasing the attack surface. Many developers don't rigorously audit or update their middleware dependencies. Why Critical: Compromising middleware can often lead directly to the attacker's goal (RCE or DoS) or provide a significant stepping stone.

Attack Tree Path: ===>[[Vulnerable Middleware (Known CVEs)]]

Description: This represents exploiting publicly known vulnerabilities (with assigned CVE identifiers) in commonly used Koa middleware packages. Why High-Risk: Public exploits are often readily available, making attacks easy to execute. Many applications run outdated or unpatched middleware. Vulnerability scanners can easily identify these issues, making them low-hanging fruit for attackers. Why Critical: Known CVEs often have documented exploits that can lead directly to RCE, data breaches, or other high-impact outcomes. Attack Steps (Example - XSS via vulnerable koa-body version): Attacker identifies a vulnerable version of koa-body is being used (e.g., via version disclosure, fingerprinting, or vulnerability scanning). Attacker crafts a malicious payload (e.g., containing JavaScript code) designed to exploit the known XSS vulnerability. Attacker sends a request to the Koa application containing the malicious payload in the request body. The vulnerable koa-body middleware processes the request body without proper sanitization. The application renders the unsanitized output (containing the attacker's payload) in a web page. The attacker's JavaScript code executes in the victim's browser, potentially leading to session hijacking, data theft, or other malicious actions.

Attack Tree Path: ===>[Improper Middleware Order]

Description: This refers to vulnerabilities arising from the incorrect sequencing of middleware. Security-critical middleware (authentication, authorization, input validation) must execute before any middleware that might be vulnerable or that processes user input. Why High-Risk: This is a common configuration error, especially in larger applications with many middleware components. It can create easily exploitable vulnerabilities even if the individual middleware components are themselves secure. Attack Steps (Example - Authentication Bypass): The application has a middleware that parses user input (e.g., koa-body) before the authentication middleware. The attacker crafts a request that manipulates the request body or headers in a way that bypasses the authentication logic. The input parsing middleware processes the malicious request before authentication. The authentication middleware, relying on the (now manipulated) request data, incorrectly grants access. The attacker gains unauthorized access to protected resources or functionality.

Attack Tree Path: [[Input Validation]] (under Custom Middleware Flaws)

Description: This represents vulnerabilities specifically stemming from inadequate or missing input validation within custom-written middleware. Why High-Risk: Custom code is more prone to errors than well-vetted, widely used libraries. Input validation is a complex task, and developers often make mistakes or overlook edge cases. Why Critical: Input validation failures are the root cause of many common web application vulnerabilities, including XSS, SQL injection, command injection, and path traversal. Attack Steps (Example - SQL Injection via custom middleware): The custom middleware takes user input (e.g., from a query parameter) and uses it directly in a database query without proper sanitization or parameterization. The attacker crafts a malicious input string that includes SQL code. The middleware constructs the SQL query by concatenating the attacker's input with the base query. The database executes the attacker's injected SQL code, potentially allowing them to read, modify, or delete data, or even execute operating system commands.

Attack Tree Path: [[XSS via Body (koa-body)]], [[SSRF]], [[Path Traversal (koa-static)]]

Description: These are specific, high-impact vulnerabilities that are often associated with particular middleware packages (though they can occur in custom code as well). They are highlighted as examples of the types of critical vulnerabilities that can arise from vulnerable or misconfigured middleware. Why Critical: XSS: Allows for client-side code execution, potentially leading to session hijacking, data theft, and defacement. SSRF: Allows the attacker to make requests to internal or external resources that the application server can access, potentially exposing sensitive data or internal systems. Path Traversal: Allows the attacker to access files outside of the intended web root directory, potentially exposing sensitive configuration files, source code, or other data.