Privilege Escalation in 5 minutes: When you’re just one URL away from becoming the Boss…

In the world of cybersecurity, privilege escalation is the ultimate “level up.” Imagine this: you’re working on an engagement, and everything seems locked down tight. Then, you stumble upon a vulnerable endpoint or misconfiguration that catapults you from an underprivileged user to an all-powerful administrator. It’s thrilling, isn’t it?

In this blog, I’ll break down the concept of privilege escalation, show you how it can happen in minutes, and share tips on how to prevent it. If you’re into penetration testing, bug hunting, or just curious about cybersecurity, this one’s for you.

Privilege escalation occurs when an attacker gains higher-level permissions on a system than initially granted. This could mean moving from a regular user to an administrator or exploiting a process to execute commands at the system level.

There are two types of privilege escalation:

Horizontal Escalation: Gaining access to another user’s account with similar privileges.

Vertical Escalation: Escalating privileges from a low-level user to an administrator or root.

You log into a web app, minding your own business, when suddenly, the URL in your browser decides to play a starring role in a security drama. That URL holds an access token, a small bundle of three parameters: id, privilege, and current privilege. These are the digital keys that tell the app who you are and what you can do. Simple, right? Well, not quite.

Here’s where things get interesting. This access token wasn’t given the VIP treatment — it’s neither validated nor encrypted. That means an attacker with little creativity (and zero respect for boundaries) can tweak those values and level up their access in the blink of an eye.

Now when a Super Admin logs into the application the access token looks something like this.

Both the tokens look almost similar except for some values like name, username and current privilege.

Now we know how both tokens of AdminUser and superAdmin User look like. Now, simply try to login into the application with the credentials of a Admin User. The trick here is, we know how token of a Super Admin looks like so we will just replace some privilege values of normal user with the privilege values of a Super Admin user.

Boom! Just like that, the attacker has promoted themselves from “Admin user” to “super admin” without going through HR. Now they’ve got front-row seats to sensitive data and all the shiny buttons that should have been off-limits.

Prevention is better than cure, especially when it comes to cybersecurity. Here are a few measures organizations can take:

Enforce Least Privilege: Limit user permissions to only what’s necessary.Validate Access Controls: Regularly test role-based access control mechanisms.Never pass sensitive authentication tokens (such as JWT tokens, session IDs, API keys) or passwords as URL parameters.

Conclusion

Privilege escalation is a serious security threat that can have devastating consequences. By understanding the attack vector and taking steps to mitigate the vulnerability, we can protect our systems and applications from this type of attack. Remember, security is an ongoing process, and it is essential to stay vigilant and proactive in protecting our digital assets.

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