Post Office Protocol (POP3)

Port: 110

1) Nmap scan

nmap --script "pop3-capabilities or pop3-ntlm-info" -sV -p 110 IP

2) Connect

telnet IP 110

3) Log in with a user

USER USERNAME
PASS PASSWORD

4) List all messages

LIST

5) Retrieve the first email

RETR 1

6) Brute force

hydra -l USER -P /usr/share/wordlists/rockyou.txt IP pop3