Security experts have identified what appears to be the first malicious software package specifically targeting unlocked Apple iPhones.

Finnish security shop F-Secure said that the Trojan installation package contains false application installation information that causes legitimate third party applications to be removed when the Trojan is uninstalled from the iPhone.

F-Secure said that the malware, which claims to be a firmware update to 1.1.3, was created by “an 11-year-old kid playing with XML files”. Fortunately the only damage the Trojan does is display the word “shoes,” but it’s when users try to uninstall the software that the software breaks many other applications.

Web sites hosting the malicious package were taken offline soon after the discovery of the low-risk threat but F-Secure said that the incident raises concerns about what a skilled malware writer could achieve.

“Hopefully this serves as a warning for those who have opened their iPhones using a security hole in the system and then installing unverified software without a second thought to what they are doing,” F-Secure said.

The malware only affects user unlocked devices and not those sold as unlocked by Apple or an operator partner.