How to URLing for Bug Bounties -Mastering URLs : Edition 2025

Hi everyone,

I am Aditya Shende (Kong) from India. A Bounty Hunter , Biker and Researcher.

This is my 14th article , If you found any spell error. Let it be….. Lets start

In the world of bug bounty hunting, understanding URLs isn’t just a skill — it’s a necessity. URLs hold the key to hidden vulnerabilities, misconfigurations, and overlooked security loopholes. Whether you’re a beginner or a seasoned hunter, mastering URL manipulation, parsing, and enumeration can significantly boost your success rate. I have written articles where you can understand How to JS for Bug Bounties 2023 Edition and JS for Bug Bounties 2024 Extreme Edition after reading this articles you will understand how we use JS for extreme hunt and once both are done you will get to know how you exploit by reading APIs , Token Article , But let me clear , you will find method , tools for it which you can do by just copy pasting and following steps . But in this lets talk about URL research how you can do it more aggressively

What is a URL?

A URL (Uniform Resource Locator) is the address of a web resource, allowing users and systems to locate and access websites, files, or APIs on the internet. Think of it as the digital equivalent of a home address — every webpage has a unique URL that directs browsers to its exact location.

A URL is structured into key components:

• Protocol (e.g., https://) defines how data is transmitted securely.
• Subdomain (www.) serves as a subset of the main domain.
• Root Domain (hostwinds.com) is the core address of a website.
• Top-Level Domain (TLD) (.com, .org, .net) categorizes sites by type or region.
• Subdirectory & Path (/blog/url-structure) indicate specific sections or content within the website.

What is Important for us right now ?

The path of URL is very important , Lets go from basics. The inurl operator helps refine Google searches by filtering results that contain specific words or patterns within the URL. This is useful for finding:

• Admin panels
• Login pages
• Debugging interfaces
• Exposed API endpoints
• Misconfigured or vulnerable web pages

By analyzing these dorks, we can identify common paths used across websites. However, to achieve more efficient results, we can combine multiple dorks for deeper exploration. But what if we shift our focus towards sensitive paths within websites and APIs? This approach could potentially lead us to discovering hidden or exposed files, revealing critical information that might otherwise go unnoticed .

To achieve this, we utilize URLscan.io or other similar search engines. Now, let’s discuss sensitive functions within a website that could expose vulnerabilities.

One such function is inviting users to a website, product, or group. Platforms like Slack, WhatsApp Groups, Instagram Groups, and other role-based websites often have invitation mechanisms. If not properly secured, these functionalities can lead to unauthorized access, information leaks, or abuse of user roles

In this URL, I initially added the path /api/user/ as part of a random search. However, if you look closely at the third URL, you’ll notice a default path that is much easier to identify—/api/user/confirm/.

The key takeaway here is to observe and analyze default paths within URLs, as they can reveal structured API endpoints or sensitive functionalities. Here’s the result of this observation:

Result is this

Now as a bug bounty POV we have to check our websites functions which are useful or not . Focus on 1. Reset Password 2. Invite User 3. Bill Payment URL on email . Just look for URLs and their paths

This is one of my email invoices containing a default path with a non-guessable string. As a bug bounty hunter, the first thing that stands out is that this URL might be indexed or accessible through external sources.

To investigate further, I checked it on the Web Archive (Wayback Machine) and discovered the following:

so here we see the path is /patron/event/view/ so my query will be : page.url:’’patron/event/view/” .

For Instagram reset here is screenshot

Now see the path and its /accounts/password/reset/confirm” and even if I take small path it can show other information for example

Understanding how URLs function and how they can expose sensitive information is crucial for bug bounty hunters. By analyzing default paths, common API endpoints, and indexed links, researchers can uncover vulnerabilities that might otherwise go unnoticed. A significant observation is that even non-guessable URLs, such as those containing invoice details or API confirmation links, can sometimes be found through various internet sources. Tools like URLscan.io and the Wayback Machine allow security researchers to check if a URL has been archived or indexed, making it publicly accessible. This approach helps identify exposed APIs, forgotten endpoints, and invitation links that could pose security risks if not properly secured.

To effectively use URLscan.io for discovering such URLs, follow these steps:

1. Basic URL Search — Use page.url:"example.com" in URLscan.io to find all publicly scanned URLs related to the target domain.
2. Searching for API Endpoints — Query page.url:"example.com/api/" to uncover exposed API routes that might contain sensitive information.
3. Identifying Sensitive Paths — Look for specific directories such as page.url:"example.com/invite/" or page.url:"example.com/payment/" to detect invitation or payment links that could be publicly accessible.
4. Checking Archived URLs — Cross-check discovered URLs with the Wayback Machine or Google Dorks to see if they were previously indexed or archived.
5. Monitoring URL Changes — Regularly analyze URL patterns on target websites to detect new paths that could reveal unintended exposure of sensitive data.
6. Responsible Disclosure — If a vulnerability is found, report it through the appropriate bug bounty program while adhering to ethical hacking guidelines.

By systematically applying these steps, bug bounty hunters can enhance their reconnaissance process and identify potential security flaws before they are exploited.

In the ever-evolving field of bug hunting, mastering URL reconnaissance can give you a significant edge in discovering vulnerabilities. By leveraging tools like URLscan.io and analyzing URL patterns, you can uncover hidden endpoints, exposed APIs, and sensitive information that others might overlook. Staying consistent, refining your techniques, and always following ethical guidelines will set you apart as a skilled security researcher.

Thank you for reading, and keep pushing forward in your bug bounty journey.

“Opportunities don’t happen. You create them.” — Chris Grosser