2013 — A man guessed or accessed the Social Security numbers…
Data compromised
Personal
Technical writeup
A man guessed or accessed the Social Security numbers of Macy's customers in order to exploit a Macy's policy for the purpose of making fraudulent purchases. He then created ID cards that paired his picture with the customer information. A Macy's policy allowed him to charge purchases to the accounts of other Macy's customers by using their Social Security numbers and showing his falsified IDs.
Root cause
Hacking: Brute force