Masscan scan udp results need to check if it is in the target

[Fxyer]

First of all, thank you for your wonderful work, a little bug here..

Phenomenon： in host 10.10.10.10 when I scan 20.20.20.20 running a task like：/bin/masscan --rate 10000 -pU:1-65535 20.20.20.20 at the some time，in host 30.30.30.30 I scan 10.10.10.10 by this command：/bin/masscan --rate 10000 -pU:1-65535 10.10.10.10 in host 10.10.10.10, I get a result that "30.30.30.30's udp port 7777 is up"，like this： Discovered open port 7777/udp on 30.30.30.30 but in host 10.10.10.10,my target is 20.20.20.20 not 30.30.30.30

Analysis： in host 10.10.10.10, host need choose a random local port as source port for packets that sniff 20.20.20.20's all udp ports , for example local port is 5555 in host 30.30.30.30, host scan all the udp ports of host 10.10.10.10, including port 5555, in host 10.10.10.10, there is a packet like: 10.10.10.10:5555 --> 20.20.20.20:1234 at the some time, host 10.10.10.10 recevie a udp packet like : 30.30.30.30:7777 --> 10.10.10.10:5555 10.10.10.10 think target response a udp packet towards it's port 5555, so report tasget's 7777 is up,but In fact 30.30.30.30 is not in targets.

because of tcp's three-way handshake model,tcp is not affected.

Solution: When find an udp port up,check if it is in the target

Wish you a happy life~~

[ameidatou]

We also encountered the same issue when using udp as some ip results were not part of our target list.

[tatulea]

I have the same issue

[TheTechromancer]

I've noticed this even on TCP scans. My system's DNS server sometimes pops up in the results, even though it's not in the target list:

{   "ip": "8.8.8.8",   "timestamp": "1716789975", "ports": [ {"port": 53, "proto": "udp", "status": "open", "reason": "none", "ttl": 56} ] }

I assume this is a side effect of masscan having its own TCP stack.

For me, this happened when running the following command:

masscan --rate 300 --wait 5 --open-only -oJ - -iL targets.txt --top-ports 100

Where targets.txt contained:

23.220.132.93/32
104.85.4.91/32
23.218.192.46/32
96.16.108.43/32
104.80.228.227/32