Big Breaches

Challenge:

How many unique emails were exposed in the biggest single collection of breached usernames/passwords? Provide the answer (flag) in the format MetaCTF{number}

Solution:

Performing a Google search for biggest single collection of breached usernames/passwords returns a result for an article on Troy Hunt’s blog, The 773 Million Record “Collection #1” Data Breach

The fourth paragraph of the article contains the answer needed for the challenge, “The unique email addresses totaled 772,904,991.”.

The accepted flag was, MetaCTF{772,904,991}