The first worm for Apple’s iPhone has been unleashed and is infecting phones.

Security experts say the worm, Ikee, is only a thread to users who have jailbroken their phones to let them run unauthorized software.

Ikee doesn’t do anything particularly bad but it could be modified to do something more dangerous such as stealing sensitive information from the iPhone.

The worm affects those IPhone with jailbroken that are running a UNIX utility called SSH (secure shell) with the iPhone’s default password “alpine”. It doesn’t affect users who used the phone in conjunction with Network Address Translation (NAT).

The worm was written Wednesday by Ashley Towns, a 21 year-old unemployed programmer from Wollogong, Australia. Towns wanted to make the point that people should change their default iPhone passwords, especially if they are using SSH.

Once the worm adds the Rick Astley wallpaper, it disable the iPhone’s SSH daemon and then looks around on the Internet for other vulnerable iPhone to infect.

Tricking victims into playing a video or looking at a picture of Rick Astley, best known for his hit “Never Gonna Give You Up” is a popular Internet prank called Rickrolling.