# sip_server_sim.py - SIP server that accepts replayed authenticated requests
from flask import Flask, request

app = Flask(__name__)
# Simulated nonce storage: doesn't track used nonces
used_nonces = set()

@app.route('/call', methods=['POST'])
def call():
    auth_header = request.headers.get('Authorization')
    if not auth_header:
        return 'Unauthorized', 401, {'WWW-Authenticate': 'Digest realm="test", nonce="abc123"'}
    # Vulnerability: no replay protection; accepts the same nonce repeatedly
    # In real SIP, a nonce should be used once; here we skip that check.
    return "Call connected"

if __name__ == '__main__':
    app.run(port=5060)