The correct answer is 'Deploy a reverse shell with a listener on the attacker's machine'. A reverse shell is designed to bypass firewall restrictions by initiating the connection from within the target network back to the attacker's controlled environment. This type of connection is less likely to be flagged by security systems compared to a bind shell, which requires the attacker to connect directly into the compromised system, thus triggering firewalls or intrusion detection systems. A VPN can provide secure communications but is not designed for establishing covert remote access from an exploited system. SSH is a secure method for remote administration but does not inherently grant persistence or stealth. Lastly, installing a new software package increases the footprint on the system and could be very conspicuous to system administrators.