Description

Detects insecure Cross-Origin Resource Sharing (CORS) configuration in Python Starlette applications where CORSMiddleware is configured to allow any origin. This creates a security risk by bypassing Same-Origin Policy restrictions, potentially allowing malicious websites to make requests to your application.

Detection Strategy

• Identifies usage of Starlette's CORSMiddleware through middleware registration

• Checks for calls to 'add_middleware' method with CORSMiddleware as the first argument

• Examines middleware configuration parameters to detect if CORS settings allow requests from any origin ('*')

• Reports a vulnerability when CORSMiddleware is configured with overly permissive origin settings

Vulnerable code example

from starlette.applications import Starlette
from starlette.middleware.cors import CORSMiddleware
from starlette.responses import JSONResponse

app = Starlette()

# ❌ Dangerous: Allows any origin with credentials enabled
app.add_middleware(...

✅ Secure code example

from starlette.applications import Starlette
from starlette.middleware.cors import CORSMiddleware
from starlette.responses import JSONResponse
from starlette.requests import Request

app = Starlette()

# ✅ Secure: Define allowed origins explicitly and restrict CORS settings...