# Cross-Site Request Forgery (CSRF) (CWE-352)

The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.

**Stack:** Python

- Prevalence: 中 3 言語をカバー
- Impact: ハイ 3 件の重大度ハイのルール
- Prevention: 文書化済み 3 件の修正例

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

## Description

When a web server is designed to receive a request from a client without any mechanism for verifying that it was intentionally sent, then it might be possible for an attacker to trick a client into making an unintentional request to the web server which will be treated as an authentic request.

## Prevention

1 件の Shoulder 検出ルールに基づく Cross-Site Request Forgery の予防策。

### Python

Ensure CsrfViewMiddleware is enabled and never use @csrf_exempt on state-changing views

## Warning Signs

- [HIGH] View handles POST/PUT/DELETE without @csrf_protect or @ensure_csrf_cookie decorator
- [HIGH] Django views that handle POST/PUT/DELETE requests without CSRF
protection

## Consequences

- アプリケーションデータの変更
- 権限の取得
- 未承認コードの実行

## Mitigations

- 状態を変更するすべてのリクエストで CSRF 対策トークンを使用する
- Referer ヘッダーを確認する
- Cookie に SameSite 属性を設定する

## Detection

- Total rules: 3
- Languages: javascript, typescript, python, go

## Rules by Language

### Python (1 rules)

- **Django Missing CSRF Protection** [HIGH]: Detects Django views that handle POST/PUT/DELETE requests without CSRF
protection. CSRF tokens prevent malicious sites from performing actions
on behalf of authenticated users.
  - Remediation: Add CSRF protection:

```python
# Option 1: Use csrf_protect decorator
from django.views.decorators.csrf import csrf_protect

@csrf_protect
def my_view(request):
    if request.method == 'POST':
        # Handle POST
        pass

# Option 2: Enable CSRF middleware (recommended)
# In settings.py MIDDLEWARE:
'django.middleware.csrf.CsrfViewMiddleware',
```