[holyjaw]

I'm a bit confused by this:

> The challenge has kubernetes logo on the bottom of the page like the screenshot below, and the IP is 35.241.245.36.

> I immediately realized that is a GCP machine, so I tested the backend server by sending HTTP request to my server to see if it is also on GCP, and it is.

What about the IP address or k8s logo made you realize it was a GCP machine?

[supakeen]

A whois on the 35.241.245.36 returns a ownership by Google with the following comment:

Comment: * The IP addresses under this Org-ID are in use by Google Cloud customers *

He then uses the SSRF to issue a request to his own server after which he likely realizes that the IP address belonging to the backend service also runs on GCP.

[leetbulb]

After working with AWS a ton, I commonly spot their IP addresses while reviewing random data sets. 50., 52., etc... This person has probably just worked with GCE a bit.

[seadog007]

I think both make me think this is a GCP machine. like if you see a A record point to 104.xx.xx.xx, then you might think this is a Cloudflare protected record.