The leaking of a trove of nude images of celebrities, including those of actress Jennifer Lawrence, has triggered a manhunt for the culprits, with the US Federal Bureau of Investigation announcing it had joined the search.
The dominant theory among analysts is that the culprit or culprits hacked the celebrities' iCloud accounts and then published the images on 4chan, an online image-sharing website.
The event has raised many questions about online security for everyday internet users at a time when most are already living "in the cloud".
iCloud accounts are cloud-based personal storage accounts that connect to Apple's online services, such as the iTunes App Store. They are a popular mechanism by which users can back up or store the content of their Apple devices, such as photos taken on iPhones.
One theory is that this was a "brute force" attack, where the attacker uses a software tool to generate multiple passwords to log into an account until they hit on the right one.
While platforms such as iCloud usually have security measures in place to identify and protect against multiple logins from the same device, hackers may have been able to circumvent such measures via a potential bug in Apple's Find My iPhone feature, which Apple has now reportedly fixed.
Earlier this month, Russian hackers claimed to have amassed billions of users' online account details. Anyone with access to such data could identify a specific target's name and then check to see if their login works on iCloud. From there, they can access files stored on a user's account, including photos, documents, emails or other information.
Tracing the culprits via 4chan may prove equally difficult. Anyone can use the site as it requires no registration.
"The whole principle of 4chan and its anonymity goes back to a perceived golden age of the internet, prior to Facebook, prior to social media," says Steve Collins, a Macquarie University media lecturer.
The leaked images are reported to have first emerged on 4chan's notorious "/b/ board" – a message board devoted to graphic imagery, often of sex and violence.
Women are not welcome on the /b/ board. Those who identify as girls or women are told to "post an image showing your breasts or get the f--- out".
Once published on 4chan, the images spread to other photosharing websites, such as imgur.
Kirsten Dunst, one of the celebrities targeted by the hackers, was quick to point the finger at Apple, tweeting: "Thank you iCloud."
But CQR Security co-founder Phil Kernick said users must take some level of responsibility for their own online security.
"I'm not into blaming victims ... but we need to make sure we protect our information a little stronger – especially if we're going to be putting sensitive info on the cloud," Mr Kernick said.
"If you don't use the same password as anywhere else, and you use two-factor authentication, then iCloud is just fine."
With Lisa Visentin
