(ABC News) - Oscar-winner Jennifer Lawrence and supermodel Kate Upton are among dozens of celebrity women who had risque photos allegedly of them leaked by an online bulletin board in an apparent hacking campaign.
According to the apparent leaker, the photos were obtained through the celebrities' cloud accounts.
The photos showed the A-listers in various states of undress.
"This is a flagrant violation of privacy," a spokesperson for Lawrence told ABC News. "The authorities have been contacted and will prosecute anyone who posts the stolen photos of Jennifer Lawrence."
Upton's attorney, Lawrence Shire, echoed those sentiments.
"This is obviously an outrageous violation of our client, Kate Upton's, privacy," he said. "We intend to pursue anyone disseminating or duplicating these illegally obtained images to the fullest extent possible."
Meantime, a representative for Ariana Grande called her allegedly leaked photos "completely fake."
Singer Victoria Justice and Olympic gymnast McKayla Maroney did the same via Twitter.
Actress Mary Elizabeth Winstead said she had deleted the photos later posted of her.
"Even if you have deleted those photos from your phone, often times they've already been uploaded into the cloud," said Clifford Neuman, the director of the USC Center for Computer System Security. "When you deleted them from the phone, they continue to exist."
Representatives for other celebrities who allegedly were hacked didn't immediately return calls for comment.
Hacking of celebrities' personal accounts has happened before. In a separate case in 2012, a Florida man was sentenced to 10 years in prison after he pleaded guilty to hacking into email accounts and stealing compromising photos of celebrities, including Scarlet Johansson, Mila Kunis and Christina Aguilera.