Whats the most anonymous active scanning technique?

[0x00pf (pico)]

@SapereAude

Yes, I’m searching and learning about that. But my concern is about the IP leakage when Nmap bypasses the Proxychain during the part of the execution, as mentioned here

If you want to understand why/how nmap leaks IPs maybe these post two post may help you to get started:

SELFPROMO MODE ON

How do those hackers' tools work? Proxychains

Welcome to this new series intended to explain the guts of all those hacker’s tools out there you use or want to use… Basically, we are going to explain you how does they work and how do you can build your own… Keep reading if you do not want to be a Skid ;). We will start the series with Proxychains. Before, keeping on reading, make sure you had read the 0x00sec introduction from @OilSlick to () ProxyChains. To understand how ProxyChains works we first need to understand how does a proxy work…

How do those hacking tools work? The Art of Port Scanning

LEVEL: Beginner Port scanning is the process of finding out which ports are open in a given machine. An open port usually means a program listening on that port, and a program means bugs, and bugs means exploits… roughly :). OK, everybody in the world uses nmap for this task. It would be stupid to write your own port scanner when such an advanced and polished tool is available. However, knowing how nmap does its magic and also, why not?, write your own simple scanner just for fun, are two valu…

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TL;DR;

Normal HTTP proxies, as well as SOCKSv4, only support TCP traffic, therefore any nmap flag that requires the transmission of UDP or ICMP packets will just not go through the proxy connection. That’s why, in your table you need to use -Pn to avoid leaking your IP by ICMP packets.

SOCKSv5 supports UDP, but looks like nmap does not support that (not yet) so, also anything that sends UDP packets will also be transmitted outside the proxy connection and therefore leak your IP. This is what happens with the -O flag. This flag will force nmap to send some UDP packets even when you specify -sT. Check the nmap documentation or the man page for details.

Anyway, as @Nitrax said, the best you can do is to try yourself and see what happens. You can use VMs or some cheap computer (Rpi) to set up a test environment and then just fire tcpdump at each end and see what you get.

Hope it helps.