The malicious software, called YiSpecter, hijacks apps and the Safari browser to show full-page ads. It fools users into installing it by claiming to circumvent China's Web censorship.
An infected, counterfeit version of Apple's Xcode developer software apparently led to dozens of compromised apps.
Despite warnings from Apple, users continue to alter their iPhones to be more flexible.
Demoed in a YouTube video, the untethered jailbreak works on the latest version of iOS, though devices with A5 chips or higher apparently are out of the running for now.
A developer has released an image of a jailbroken iPhone 5 running the latest version of iOS 6, likely to be superseded by iOS 7 very soon.
A vulnerability could allow hackers to trick users into downloading fake apps, which could siphon off their personal information, researchers warn.
The vulnerability affects roughly 95 percent of all Apple mobile devices currently in use, according to a new report.
A new kind of malicious software strikes at Mac OS X and iPhone users in China, according to a just-released security report.
FinSpy spyware can hack its way into Android, BlackBerry, and older versions of Windows Phone but can't touch iOS unless the device is jailbroken, according to a leaked report from Gamma Group.
The video shows a jailbroken iPhone 5C restarted and then still able to access Cydia to manage the device.