Network problems - nmap and ping

Off-topic
1

Hi all,

I am facing some strange behavior with my openVpn connection, which I identified when nmap behaved inconsistent.

Sometimes it works, sometime I do get this

└─$ nmap -sC -sV 178.62.0.100
Starting Nmap 7.91 ( https://nmap.org ) at 2021-01-06 22:10 CET
Note: Host seems down. If it is really up, but blocking our ping probes, try ->Pn
Nmap done: 1 IP address (0 hosts up) scanned in 4.39 seconds

also

nmap -F 178.62.0.100
works sometimes, sometimes not.

I checked my IP, I have tun0 in ifconfig and on the HTB WebApp Dashboard the IP is the same.

When I do ping the host, in this case the “Youknow 0xDiablos” machine, I get 100% packet loss.

I also changed the .ovpn from UDP to TCP and still I have the same issues.

Someone experienced the same behavior? What did you do to fix this issue?

Any help appreciated.

2

So a lot of this is down to what target you are scanning. In general troubleshooting tracert/traceroute works well but here I think its something else.

The IP address 178.62.0.100 is not on the HTB private network, so you shouldn’t need to connect via OpenVPN.

When you start the instance for this challenge you are given an IP:PORT which is accessible over the public internet. You can’t nmap it because only a single port is exposed to you. Generally this port is outside the normal range for nmap (often in the 3xxxx range)

This isn’t a pentest challenge - its a pwn challenge, so the binary listening on the port which you can download to examine, responds to your exploit attacks.

3

Hi TazWake,

thanks a lot for that explanation, it explains everything.

So when the IP is 10.10.. it is inside VPN and I need a connection.

Really interesting.

4

@P3ntbtt3r said:

Hi TazWake,

thanks a lot for that explanation, it explains everything.

So when the IP is 10.10.. it is inside VPN and I need a connection.

Really interesting.

10.x.y.z, to be more precise, because the Fortress and Endgame machines (and ProLabs probably, too) are in other subnets than just 10.10.x.y :wink:

5

Hi HomeSen,

didn’t touch one of those, I am new to HTB.

Thanks!

6

No problem. I just wanted to mention it, in case you look at them, later :wink:

As a rule of thumb: When it’s a private IP address, you will need the VPN. All other IPs can be reached directly from any computer, but only on the port(s) mentioned at the according challenge/page.

7

I faced the same issue when I updated my Kali and somehow managed to mess up installing grub. After reinstalling Kali and properly checked the right drive to install grub the openvpn connection works again.