Apple said on Tuesday that user accounts belonging to some celebrities were compromised in a targeted attack, but said there were no signs of a wider breach of its iCloud service.
"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," Apple said in a statement.
"None of the cases we have investigated has resulted from any breach in any of Apple’s systems including iCloud® or Find my iPhone," the statement continued.
"We are continuing to work with law enforcement to help identify the criminals involved," Apple said.
“The hack was a two part attack. The first part of the attack was obtaining the email addresses (Apple IDs) of the targets," Philip Lieberman, President and CEO of Lieberman Software, told SecurityWeek. "The second part of the attack was understanding that the iCloud service had a flaw that allowed an unlimited number of bad password attempts without lockout or alerting. Knowing that the iCloud service did not lock out bad password attempts allowed the attacker to try different lists of works, phrases and character combinations from existing dictionaries of words (dictionary attack) and ultimately use every possible combination of letters, numbers and punctuation via a brute force attack if desired."
"Apple should have logs containing IP addresses of all parties connecting to their services and using this information, they should be able to quickly identify attackers executing large numbers of logon attempts," Lieberman continued.
"This does beg the question of Apple’s incompetence in security operations. They should have detected large numbers of logon attempts from a specific address in a short period of time, and their iCloud system should have provided lockout functionality after a fixed number of bad passwords. The technology to protect their clients from these attacks is trivial to implement and costs little to operate."
"To be clear, Apple was not penetrated, they simply were using a lock on their customer’s accounts that was commercially incompetent," Lieberman said. "However, since Apple customers agree to an End User License Agreement (EULA) that effectively limits Apple’s liability to effectively zero, Apple has little to no direct financial damage, but reputation damage could be significant. Users should remember that they are using a consumer grade service with Apple and that much more secure systems exist for file storage and should be used for sensitive data.”
Apple advised users to always use a strong password and enable two-step verification.