Documentation or source on liveness detection?

[dietervds]

Hi folks!

Can anyone point me to code or documentation that shows how liveness is determined when Nuclei scans a (private) IP range?

For example, when we run nuclei -u 192.168.1.0/24, will it just send a probe to 80 and 443 and depend on, for example, Naabu or Nmap to do the discovering, or is there more at work?

I've combed through the docs trying to find the answer but came up short. Apoligies if I did overlook it.

[dogancanbakir]

Could you clarify what you mean by liveness? For example, there's probing with httpx that isn't explicitly documented, but you can find some related configuration options. I'm happy to help if you'd like more details! Also, for the docs see here https://docs.projectdiscovery.io/opensource/nuclei

[dietervds]

@dogancanbakir Thanks for the reply! And apoligies for the lateness of mine.

I indeed meant to find out what kind of probes Nuclei (/httpx) sends to determine if a host is alive or not, before it "unleashes" all the appropriate templates. From my testing back then it seemed like it only sent web-based probes (80 and 443), which meant it didn't seem to notice hosts that only had an RDP port open, for example.

It would be wonderful to read more about how httpx does its probing, but either way, we ended up putting Naabu in front of the Nuclei scan, and use that to explicitly gather a list of live hosts, before handing it to Nuclei for proper vulnerability scanning. I presume that that is the way to go, but I didn't realise that at the time.

Any feedback on the above is welcome, even just for posterity. But most of all: thank you for the awesomeness that your team brings to the open source world :-) Cheers!

[dogancanbakir]

No worries! I won't be able to say much without knowing the whole pipeline and the definitions. But, this one thing I believe is worth recommending, knowing the tool you're using is the most important when it comes to system design in general.

I'm happy to chat more, but thank you for replying and your kind words!