Apple on Tuesday offered more insight into the hack that started a massive online leak of celebrity nude photos over the long weekend.
Celebrities' accounts were individually targeted, Apple said. There was no systemic hack of its iCloud storage system.
"After more than 40 hours of investigation, we have discovered that certain celebrity accounts were compromised by a very targeted attack on user names, passwords and security questions, a practice that has become all too common on the Internet," the company said.
Apple is working with law enforcement to help catch the person responsible, and recommends that iCloud users take advantage of two-step verification to keep their personal photos safe from prying eyes. (Here's a guide to keeping your iPhone photos safe from hacks.)
Apple made it clear in its statement that no specific bug or vulnerability in its code caused the attack.
"None of the cases we have investigated has resulted from any breach in any of Apple’s systems including iCloud® or Find my iPhone," Apple said in a statement on Tuesday.