In the final stage, APT3 attempts to exfiltrate sensitive data using encrypted channels, aiming to evade detection mechanisms. The operation was detected when unusual encrypted traffic was observed between internal host 192.168.1.45 and an external IP address 203.0.113.5. The malicious file 'encrypted_payload.zip' with hash 'd41d8cd98f00b204e9800998ecf8427e' was involved in the exfiltration attempt.