This means that iPhone owners who don't have a jailbroken device could rest assured that their phone has not been hacked. Jailbreaking is actually the name of a process that allows iPhone owners to access parts of their phone's file systems which are normally restricted by Apple, precisely for security reasons.
The new hack, named KeyRaider, is believed to be mostly found on Chinese websites that provide software to jailbreak iPhones or apps for jailbroken devices. However, this does not mean that only Chinese owners of jailbroken iPhones were affected by this hack. The malware is known to have spread beyond China, about 18 countries being affected until this point.
The malware is quite strong and has the ability to access all the information that users might have on their devices. This includes usernames, passwords, but also unique iPhone IDs. The malware also steals user's information on App Store purchases. This is quite a serious situation for customers, as this means that purchases can be made from their accounts.
Some of the victims of this hack have been in the situation of seeing their accounts paying for purchases from the App Store, made by other people. This means that hackers have sold users information or have allowed other people to take advantage of the hacked accounts. A software used by hackers allows other people to make purchases from these accounts for free. This software has actually been accessed by no less than 20,000 people, who had stolen from the 225,000 iPhone owners affected by the hack.
Apple has not commented on this situation, but the company bears no responsibility for the devices that have been jailbroken. Apple puts a lot of efforts and focus into avoiding such hacks, this is why its security is so enhanced. However, when iPhone owners jailbreak their devices, that security is easy to compromise and Apple has no responsibility for what might happen.