Bypassing 403 Forbidden Errors: Manual and Automated Techniques
When you encounter a 403 Forbidden Error while bug hunting or exploring a web server, it means you lack authorization to view a particular page or resource. Many users give up at this point, but bypassing these restrictions can reveal hidden admin pages or other sensitive areas, potentially leading to valuable findings and bug bounty rewards. This tutorial walks you through several manual bypass techniques and introduces tools for automating the process.
Manual Bypass Techniques
1. Request Method Manipulation
Convert a GET request to a POST request to bypass certain restrictions.
GET /admin HTTP/1.1Host:target.com
Change to:
POST /admin HTTP/1.1Host:target.com
2. Overriding the Target URL via Non-Standard Headers
Use headers like X-Original-URL or X-Rewrite-URL to trick the server into serving restricted content.
GET /anything HTTP/1.1Host:target.comX-Original-URL: /admin
Or:
GET /anything HTTP/1.1Host:target.comX-Rewrite-URL: /admin
3. Appending %2e After the First Slash
Insert %2e (URL-encoded dot) after the first slash to bypass filters.
Original:
Bypass:
4. Using Dots (.), Slashes (/), and Semicolons (;) in the URL
Modify the URL structure with special characters to evade access controls.
Examples:
5. Adding “..;/” After the Directory Name
Append ..;/ to the directory path.
Original:
Bypass:
6. Uppercasing Characters in the URL
Change the case of letters in the URL.
Original:
Bypass:
7. Web Cache Poisoning
Leverage web cache behavior with headers to access restricted resources.
Automation Bypass
Several tools can automate the process of bypassing 403 and other 40X status codes. Here is a curated list:
These tools can automate header manipulation, URL fuzzing, and other techniques, saving time and increasing your chances of finding a successful bypass.
