Testing For Open Redirect Vulnerabilities

# Testing for Open Redirect Vulnerabilities

## When to Use
- When testing login/logout flows that redirect users to specified URLs
- During assessment of OAuth authorization endpoints with redirect_uri parameters
- When auditing applications with URL parameters (next, url, redirect, return, goto, target)
- During phishing simulation to chain open redirects with credential harvesting
- When testing SSO implementations for redirect validation weaknesses

## Prerequisites
- Burp Suite or OWASP ZAP for intercepting redirect requests
- Collection of open redirect bypass payloads
- External domain or Burp Collaborator for redirect confirmation
- Understanding of URL parsing and encoding schemes
- Browser with developer tools for observing redirect chains
- Knowledge of HTTP 301/302/303/307/308 redirect status codes


> **Legal Notice:** This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

## Workflow

### Step 1 — Identify Redirect Parameters
```bash
# Common redirect parameter names to test:
# ?url= ?redirect= ?next= ?return= ?returnUrl= ?goto= ?target=
# ?dest= ?destination= ?redir= ?redirect_uri= ?continue= ?view=

# Search for redirect parameters in the application
# Use Burp Suite to crawl and identify all parameters

# Test basic redirect
curl -v "http://target.com/login?next=https://evil.com"
curl -v "http://target.com/logout?redirect=https://evil.com"
curl -v "http://target.com/oauth/authorize?redirect_uri=https://evil.com"
```

### Step 2 — Test Basic Open Redirect Payloads
```bash
# Direct external URL
curl -v "http://target.com/redirect?url=https://evil.com"

# Protocol-relative URL
curl -v "http://target.com/redirect?url=//evil.com"

# URL with @ symbol (userinfo abuse)
curl -v "http://target.com/redirect?url=https://[email protected]"

# Backslash-based redirect
curl -v "http://target.com/redirect?url=https://evil.com\@target.com"