CUPERTINO (CBS SF) — Apple says an investigation into the rogue posting of more than 100 nude celebrity photos stemmed from a targeted hacking attack on celebrity accounts, rather than a breach of security into the iCloud system as originally reported.

In a media statement, Apple said:

READ MORE: California Drought: Healdsburg Bans Sprinklers; Sets Personal Water Use To 74 Gallons A Day

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. None of the cases we have investigated has resulted from any breach in any of Apple’s systems including iCloud® or Find my iPhone. We are continuing to work with law enforcement to help identify the criminals involved.

Apple also said it urged users to always use strong passwords and enable two-step verification.

READ MORE: 3-Alarm Fire Burns 2 Buildings at West Oakland Recycling Center

The FBI said it was also investigating how the accounts of celebrities such as Jennifer Lawrence, Kate Upton, and Kim Kardashian had been hacked. The hacking led to a dozens of nude photos being leaked on the often not-safe-for-work message board 4chan before being spread to multiple other Internet sites.

One of the purported hackers suggested iCloud was the source of the photos, leading to accusations of some type of security hole in Apple’s cloud storage system.

Meawhile, a tool surfaced on code-sharing site Github that could have allowed hackers to breach the Find My iPhone application by allowing multiple attempts to enter a password without being locked out of the account.

MORE NEWS: Update: One Killed, Two Injured When Truck Crashes Into Diners at San Jose Sports Bar

PROTECT YOUR PICS: Your phone might be uploading every photo you take
ON TWITTER: Celebrities Rage, Claim Photos Fake; Ricky Gervais Jokes Via Tweet