One of the drawbacks to jailbreaking your device is that it is no longer running the way that Apple had originally intended for it to run. This means that your device could be open to more crashes, apps could modify it in a bad way, and there could be security holes as well.
According to a recent discovery by security research, Stefan Esser, it has been discovered that there is a piece of malware that has infected jailbroken devices, thus causing them to crash. Not only is a device that crashes pretty annoying, but it turns out that this piece of malware has a more sinister purpose, which is to steal Apple ID and password information from said device.
According to Esser’s discovery, “This malware appears to have Chinese origin and comes as a library called Unflod.dylib that hooks into all running processes of jailbroken iDevices and listens to outgoing SSL connections. From these connections it tries to steal the device’s Apple-ID and corresponding password and sends them in plaintext to servers with IP addresses in control of US hosting companies for apparently Chinese customers.”
However thankfully the malware does not appear to have originated from Cydia, but rather an outside source. It has also been discovered that the malware only affects 32-bit devices so if you have an iPhone 5s, an iPad Air, or an iPad mini with Retina display, you should be safe. Unfortunately removing the malware is not a particularly easy task and will require users to fully restore their devices, thus removing the jailbreak.