Interesting blocklist traffic

I just started using a new IP Blocklist and while reviewing Firewall log (blocklist), I found very interesting traffic involving Protocol 47

Just for information

It is possible that the attacker is attempting to exploit vulnerabilities in the GRE protocol.

e.g.

Regards

What would be the reason behind an attack using Protocol 47 ?

There is not even a destination port recorded.

GRE doesn’t use ports.

https://david-waiting.medium.com/a-beginners-guide-to-generic-routing-encapsulation-fb2b4fb63abb