Bug Hunting is easy if you KNOW this

Summary

This video reveals the simplicity of exploiting Insecure Direct Object References (IDOR), a web application vulnerability that can lead to significant data breaches. The presenter shares seven effective techniques for bug bounty hunters to identify IDORs, including examining URL parameters, manipulating UUIDs, and testing various HTTP methods. A notable example from 2021 illustrates how a bug hunter earned $49,500 by exploiting this vulnerability on Instagram. Additionally, the video highlights the risks of combining IDOR with cross-site scripting (XSS). Viewers are encouraged to access a free cheat sheet for further insights and learning.

Takeaways

• 😀 IDOR (Insecure Direct Object Reference) is a significant web application vulnerability that allows attackers to access unauthorized resources by modifying parameters in URLs or API requests.
• 😀 A bug hunter earned a $49,500 bounty from Facebook in 2021 by exploiting an IDOR vulnerability in Instagram, which allowed them to change thumbnails of other users' reels.
• 😀 Key parameters to look for when hunting for IDOR vulnerabilities include user IDs, media IDs, and file IDs in URLs.
• 😀 Universally Unique Identifiers (UUIDs) may seem secure but can still have vulnerabilities; look for leaks in logs and test for custom UUID generation weaknesses.
• 😀 Parameter pollution can be used to exploit vulnerabilities by adding multiple user IDs to requests, potentially gaining access to data of multiple users.
• 😀 Testing different HTTP methods (GET, POST, PUT, PATCH, DELETE) can reveal additional IDOR vulnerabilities that might not be evident with just GET and POST.
• 😀 If encountering encoded parameters (like Base64), decoding and modifying them can lead to unauthorized access to different files or data.
• 😀 Fuzzing endpoints by changing version numbers and appending different terms can uncover hidden or undocumented endpoints susceptible to IDOR vulnerabilities.
• 😀 When no ID is present in the URL, appending potential ID parameters can help identify access points, especially in cases where generic terms like 'self' are used.
• 😀 Combining IDOR vulnerabilities with Cross-Site Scripting (XSS) can create severe security issues, allowing attackers to store malicious scripts in other users' workspaces.

Q & A

What is Insecure Direct Object Reference (IDOR)?

IDOR is a type of access control vulnerability where an application allows users to access objects directly using user-supplied input without proper authorization checks.

How can IDOR vulnerabilities impact users?

IDOR vulnerabilities can lead to unauthorized access to sensitive data, personal information leaks, and manipulation of data, potentially affecting millions of users.

What notable example demonstrates the severity of IDOR?

In 2021, a bug hunter earned a $49,500 bounty from Facebook for exploiting an IDOR vulnerability in Instagram Reels, which allowed them to change thumbnails on other users' reels.

What are the key parameters to look for when hunting IDOR vulnerabilities?

Focus on URL or API request parameters, especially those involving IDs, such as user IDs or media IDs, which may be susceptible to manipulation.

What techniques can be used to test UUIDs for IDOR vulnerabilities?

Check for leaks in logs or error messages, verify if UUIDs are genuinely non-guessable, and try replacing complex UUIDs with simpler numeric sequences.

What is parameter pollution and how can it help in finding IDOR vulnerabilities?

Parameter pollution involves adding multiple user IDs to a request to see if the backend accepts them, which may expose data from other users.

Why is it important to test different HTTP methods in IDOR hunting?

Different HTTP methods like PUT, PATCH, and DELETE may reveal vulnerabilities that are not apparent through standard GET or POST requests.

How can encoded or hashed IDs be exploited in IDOR hunting?

By decoding encoded parameters (e.g., Base64), modifying the ID, and re-encoding it, attackers may gain access to restricted files.

What is fuzzing and how can it be used to find IDOR vulnerabilities?

Fuzzing is a testing technique where various inputs are submitted to an application to uncover hidden endpoints or security flaws, such as incorrect handling of ID parameters.

What is the significance of combining IDOR with Cross-Site Scripting (XSS)?

Combining IDOR with XSS can greatly amplify the impact of an attack, allowing malicious scripts to affect other users, particularly if an attacker can manipulate parameters that affect multiple user sessions.