Security Hardening

[jsolejr]

I am interested in branching to experiment with some ideas to harden the code and preventing exposure to potential security issues.

Possible security issues I am interested in trying to harden:

1. Lack of Input Validation: The code does not validate user inputs, such as the url, id, and text parameters. This can lead to various security vulnerabilities, including URL manipulation, injection attacks, and cross-site scripting (XSS) attacks. It is important to validate and sanitize user inputs before using them in the code.

2. Error Handling: The code uses a broad exception handling block with a generic except statement, which catches all exceptions without providing specific error messages. This can make it difficult to identify and handle specific errors, and it can also expose sensitive information in error messages. I think was identified in another issue thread.

3. Code Execution from User Input: The code uses the evaluate method to execute JavaScript code passed as strings. If user-supplied input is directly used in these evaluated JavaScript snippets, it can lead to code injection vulnerabilities. It is crucial to validate and sanitize user inputs before executing them as code.

4. Use of Global Variables: The code uses global variables (browser, page, client, page_element_buffer) to store state information. Using global variables can make the code more error-prone, harder to maintain, and vulnerable to potential race conditions in a multi-threaded environment. It is recommended to use local variables or encapsulate the state in a more controlled manner.

5. Lack of Content Security Policy (CSP): The code does not implement or enforce a Content Security Policy. CSP helps prevent various types of attacks, such as XSS and data injection, by restricting the sources from which certain types of content (e.g., scripts, stylesheets) can be loaded. Implementing a strong CSP can enhance the security of the application.

6. Potential Clickjacking Vulnerability: The code removes the target attribute from all <a> elements on the page using injected JavaScript. This can potentially introduce a clickjacking vulnerability, where an attacker tricks users into clicking on a hidden or disguised element by overlaying it with a malicious element. It is advisable to use other methods, such as adding the rel="noopener" attribute, to improve the security of links instead of removing the target attribute.

7. Blacklisted Elements: The code maintains a set of blacklisted elements and skips processing them. However, the list of blacklisted elements is limited and may not cover all potentially dangerous elements. It is recommended to use a whitelist-based approach instead, where only known safe elements are allowed, to mitigate potential security risks.