CVE-2023-5036, a bunch of scary sounding numbers and letters, right? But what exactly does it mean? In simple terms, it's an identifier—a ticket, if you will—to a known software vulnerability. In this in-depth post, we'll look at a particular vulnerability affecting the usememos/memos GitHub repository prior to version .15.1 and talk about its details, how it can be exploited, and ways to protect against it. Strap in, it's going to be a wild ride!

Context: A Quick Look at usememos/memos

Before diving into the vulnerability itself, let's provide some context. Usememos/memos is an open-source project hosted on GitHub. It's a web-based application designed to help users easily create and organize memos, acting as a _very_ useful digital sticky note wall.

Vulnerability: Cross-Site Request Forgery (CSRF) Explained

Cross-Site Request Forgery (CSRF) is a type of web security vulnerability that lets an attacker trick an innocent user into performing an unwanted action on a website. Imagine the following scenario: you're logged into your bank's website and, unknowingly, visit a malicious site that wants to perform an unauthorized transfer from your account. If the bank's website is vulnerable to CSRF, the attacker can execute the transfer _as if_ it's coming from you. In most cases, the user doesn't even realize anything has happened.

Exploit Details: The Nitty-Gritty of CVE-2023-5036 in usememos/memos

In the case of CVE-2023-5036, the usememos/memos project has a CSRF vulnerability that affects all versions prior to .15.1. This means an attacker can create a malicious link or script that, when clicked or executed by a user, can perform unwanted actions on a user's memos. This could include editing, deleting, or even sharing these memos without the user's knowledge or consent.

As an example, consider the following piece of code, which demonstrates an exploit

<!DOCTYPE html>
<html>
	<body>
		<form action="https://usememos.example.com/memo/12345/edit"; method="POST" id="csrf_form">
			<input type="hidden" name="memoContent" value="This memo has been edited without your knowledge!" />
			<input type="hidden" name="submit" value="Save" />
		</form>
		<script>
			document.getElementById("csrf_form").submit();
		</script>
	</body>
</html>

In this code snippet, we create a hidden form that sends a POST request to the Usememos server to edit a memo (let's say memo ID 12345). The malicious script inside the form then gets executed automatically once loaded, submitting the form and changing the content of the targeted memo. If you're not familiar with HTML or JavaScript, don't worry; just know that this is not something users would want to happen!

The vulnerability (CVE-2023-5036) was first publicly disclosed in the following advisory

- Vulnerability Advisory: CSRF in Usememos/memos

Additionally, the usememos/memos GitHub repository has information about the issue and the patched version:

- usememos/memos GitHub Repository

Solution: How to Protect Yourself

The best way to protect against this vulnerability is to update your usememos/memos installation to the latest version (.15.1 or newer). You can do this by following the official upgrade instructions provided on the GitHub repository.

Using Security Headers like Content-Security-Policy and SameSite attribute for cookies can also help protect against CSRF vulnerabilities.

Conclusion

We have explored CVE-2023-5036—a Cross-Site Request Forgery vulnerability affecting the usememos/memos GitHub repository. We talked about the context of the usememos/memos project, the details of the CSRF exploit, where to find original references, and how to protect against this type of vulnerability. Vulnerability management is an essential part of any software project, and staying up-to-date with the latest patches and best practices is key to ensuring the safety of your web applications. Remember to keep an eye on your project dependencies and subscribed advisories to stay ahead of potential threats.

Timeline

Published on: 09/18/2023 06:15:00 UTC
Last modified on: 09/19/2023 13:18:00 UTC