The FBI is investigating allegations that intimate pictures of celebrities have been stolen and circulated online.
Around 20 personalities including Rihanna, Kim Kardashian and US actress Jennifer Lawrence have been targeted by the hackers.
It is believed that some of the images were obtained from online services, such as Apple's iCloud, which automatically backs up devices on the Internet.
Ms Lawrence, famous for her role as Katniss Everdeen in The Hunger Games films, has requested an investigation after photos containing graphic content were posted online.
A spokeswoman for the actress said the Internet posts were a "flagrant violation of privacy."
Apple is currently investigating the matter, but the incident has led a number of experts to question the security of cloud storage sites.
"It is important for celebrities and the general public to remember that images and data no longer just reside on the device that captured it," said Ken Westin, security analyst at Tripwire.
"Although many cloud providers may encrypt the data communications between the device and the cloud, it does not mean that the image and data is encrypted when the data is at rest.
The images were originally leaked on imageboard website 4chan, before being spread to other online services, such as Reddit, Imgur and Twitter.
While some of the images were fakes, a number of celebrities have confirmed the authenticity of the pictures.
According to the BBC (opens in new tab), an FBI spokesman told the Associated Press that it was aware of the leaked images and was "addressing the matter."
Raj Samani from Intel Security said that more often than not it is a human weakness that gives hackers the opportunity to compromise accounts. Often, "phishing" people, or tricking them into revealing their password, is the simplest way to gain access.
"Almost every service used online requires a password, and to ensure your passwords are secure, they must be complex," he added.