I don't get it.

A friend of mine back in 2005 cloned a school computer's drive to his iPod, took it home, and brute forced the admin password using rainbow tables on his gaming PC.

It was Admin_2000, and it was shared by every computer in the school district.

https://emudhra.we-have-a-problem.com/

Thanks, but I read all of it and I still don't understand what it has to do with "Mellon" and "4"

ELI5?

One of the private keys was just “4”. This is basically the certificate authority’s master password, which allows them to securely sign their certificates. It is supposed to be hilariously long and complex, to make brute-forcing it virtually impossible. And it was just… 4.

Not sure where Mellon comes into play though.

Isn't it the password for the Moria in LOTR ? And a pretty simple one ?

Reminds me of a story from my mom's childhood: growing up in the 50s far out in the country, people having telephones was somewhat of a rarity, so the numbers were quite short.

"How short?", you ask?

The telephone number of the local butcher was "1".

Yeah, the "riddle" is "speak friend and enter" and it turns out that all you have to do is say "friend" in Sindarin (Grey-Elven), which is "mellon"