The title of this article is the first 5 minutes, so this method is likely not to work for all, but for some it could be a quick way to gain a foothold.
This information is gathered from capturing several flags on HTB and following walkthroughs and writeups of mostly Easy boxes. The enumeration steps are almost identical to start enumeration to gain a foothold to pivot to privilege escalation.
Use this approach and see how much loot you can gather. If you don’t get enough for initial access, turn up the volume.
The quiet approach of knocking on only a few common ports to start. This approach was adopted since almost all these boxes that are Linux start with port 80.
Add hosts to your /etc/hosts file:
10.129.10.10 host host.htb
Since most of the HTB boxes use their hostname, you can start enumeration with that information for gobuster and ffuf:
gobuster dns -d host -w wordlist
gobuster dns -d host.htb -w wordlist
gobuster vhost -u http://host -w wordlist
gobuster vhost -u http://host.htb -w wordlist
ffuf -u http://host/FUZZ -w wordlist
This list is small and limited, but a good start.
nmap -p 21,22,23,25,80,443,8000,8080
Using -v will printer the headers.
curl -v http://host