In a move to swiftly quell a gathering storm, on Monday, Apple pulled applications in its App Store created by a Vietnam-based developer who may have manipulated ratings and hacked user accounts. The company also issued a warning to users to change their passwords.

The iTunes books category

The developer, Thuat Nguyen, allegedly entered iTunes accounts and manipulated the ratings for his book apps. On Sunday, several technology-enthusiast sites were reporting, including ours, that the developer’s applications had claimed 42 of the top 50 books in terms of revenue. At the same time, some users also reported unexplained iTunes charges on their accounts, reflecting hundreds of dollars for purchases of Nguyen’s books.

Fraudulent Purchase Patterns

On Tuesday, Apple said Nguyen and his apps “were removed from the App Store for violating the developer program license agreement, including fraudulent purchase patterns.” The titles in question, which have been removed from the App Store, were largely Japanese manga titles.

Apple noted that “developers do not receive any iTunes confidential customer data when an app is downloaded,” but it also recommended that all users change their iTunes account password “immediately.” The company also suggested that, if a credit-card or iTunes password was stolen and used, the credit-card company should be contacted right away.

The story has brought to the fore various reports of widespread hacking of iTunes accounts, many of which appear to be organized out of China. According to these reports, iTunes accounts are compromised for 24 hours or less, during which time hundreds of dollars of fraudulent charges are posted.

Some regular iTunes developers, such as Alex Brie, had noted suspicious activity in recent days and sent the information to Apple. Brie wrote on his blog that the App Store team started an investigation not long after he noted that his applications were mysteriously losing position to the low-quality manga titles.