In what's clearly been a busy weekend for hackers, reports are appearing that there has been suspicious activity over at the iTunes App Store.
Users are reporting that unauthorized purchases are appearing on their accounts - purchases of book applications from Vietnamese developer Thuat Nguyen. Most of these are rather poor-quality Manga titles.
At one point, the high volume of sales propelled Nguyen's apps to take over 40 of the top 50 book app slots in the store.
"I recently checked my credit card account activity online and found the same pattern described throughout this thread. Unauthorized iTunes charges that, for me, came out to about $188," wrote one user on the MacRumours Forum.
"First one was $1.29, then the next five were between $40 - $50 (although one was for $12.68), then another for $2.11 this month. So far seven charges in all before I caught it and closed down my account. Not sure if some are still in the pipeline."
The attacks appear not to have happened on a massive scale, and Apple has now removed the offefnding books from the store.
"This is a new kind of internet theft - the first of its kind that I hear of - and such a vulnerability is a major threat to all that Apple’s AppStore ecosystem means: a safe, secure place for people to download legitimate and curated apps," says rival developer Alex Brie.
Brie says Apple's senior vice president of worldwide product marketing Phillip Schiller has promised to investigate.
He adds: "The developer itself doesn’t seem to be legit – both the company site and support page are missing. No reference to them could be found on Google."
YouTube was also hacked over the weekend, with Justin Beiber fans being redirected to porn sites.