Snapchat usernames and phone numbers were lifted in an attack by hackers after the company basically ignored the warnings that they were vulnerable.

The hackers have released a redacted database of 4.6 million usernames and phone numbers (minus two digits) through a site called SnapchatDB.

Snapchat put out a memo dismissing the lack of rate-limiting as no great concern:

"Theoretically, if someone were able to upload a huge set of phone numbers, like every number in an area code, or every possible number in the U.S., they could create a database of the results and match usernames to phone numbers that way. Over the past year we’ve implemented various safeguards to make it more difficult to do. We recently added additional counter-measures and continue to make improvements to combat spam and abuse."

Hackers picked up the implied challenge to prove Snapchat wrong.