Yes, there is now a Trojan for the Mac OS X-based iPhone. Reports say that this Trojan is “mild”. If you are an iPhone user who has modified the phone to install third party utilities, you are at risk.

This new iPhone Trojan goes by the name “iPhone firmware 1.1.3 prep.” It is also called “113 prep”. You may be fooled that it is an essential system upgrade. If you install this Trojan onto your iPhone, it seems to do little more than displaying “shoes” on your iPhone screen.

However, this Trojan overwrites applications such as “Erica’s utities” along with “Open SSH”. If you try to uninstall the Trojan, even these applications get deleted. Although this Trojan is not extremely risky and does not cause a great deal of harm, it is still a source of worry.

After uninstalling the Trojan, you will need to reinstall the deleted apps to get back to normal. It seems this Trojan was created by a 11 year old kid while playing with XML files.

According to security vendors, this will serve as a warning to people opening iPhones through a security hole and installing unverified software.