# URL Redirection to Untrusted Site ('Open Redirect') (CWE-601)

A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect.

**Stack:** Python

- Prevalence: Moyenne 3 langages couverts
- Impact: Moyen Revue recommandée
- Prevention: Documentée 4 exemples de correctifs

**OWASP:** Broken Access Control (A01:2021-Broken Access Control) - #1

## Description

An open redirect vulnerability occurs when an application takes user input and uses it to redirect the user to a different URL. Attackers can exploit this to redirect users to malicious sites.

## Prevention

Stratégies de prévention pour Open Redirect basées sur 1 règles de détection Shoulder.

### Python

Validate redirect URLs against a domain allowlist or use relative paths

## Warning Signs

- [MEDIUM] unvalidated redirects using user input

## Consequences

- Obtenir des privilèges
- Contourner le mécanisme de protection

## Mitigations

- Validez les URL par rapport à une liste d'autorisation de domaines de confiance
- Utilisez un système de mapping plutôt que des paramètres d'URL directs
- Affichez des pages d'avertissement avant de rediriger vers des sites externes

## Detection

- Total rules: 4
- Languages: go, javascript, typescript, python

## Rules by Language

### Python (1 rules)

- **Open Redirect** [MEDIUM]: Detects unvalidated redirects using user input.
  - Remediation: Validate redirect URLs against an allowlist of permitted domains.

```python
from urllib.parse import urlparse
ALLOWED_DOMAINS = {"myapp.com"}
if urlparse(url).netloc not in ALLOWED_DOMAINS:
    url = "/"
```

Learn more: https://shoulder.dev/learn/python/cwe-601/open-redirect