The signal is Steam Guard emails. I do assume it is brute force/password spray. More details in sibling reply: https://news.ycombinator.com/item?id=25739283 h

The signal is Steam Guard emails. I do assume it is brute force/password spray. More details in sibling reply: https://news.ycombinator.com/item?id=25739283 https://news.ycombinator.com/item?id=25739283