404 to $4,000: Exposed .git, .env, and Hidden Dev Files via Predictable Paths

How Bug Bounty Hunters Can Turn Common 404s Into Critical Information Disclosure Bounties

Monika sharma

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Jun 3, 2025

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Introduction

In the age of aggressive automation and CI/CD pipelines, developers often forget to secure files and directories not meant for public eyes. While these files return a 404 or remain hidden from the UI, they may still be accessible — and a goldmine for bug bounty hunters.

From .git/config to .env, debug.log, composer.lock, swp, and ~ backup files, even a single forgotten file can lead to source code disclosure, credential leakage, or privilege escalation.

In this article, you’ll learn how to hunt for these hidden dev files, tools to automate it, and what to do when you find one.

Common Hidden Files to Look For

File/Folder:

1. .git/config

Impact — Git repo leak, commit history

2. .env

Impact — AWS creds, DB passwords, JWT secrets

3. debug.log

Impact — Internal error stack traces

4. composer.lock