Security researchers have detected the first malware for Sony's Playstation Portable (PSP).

The Trojan masquerades as a download tool that promises to modify the firmware on the gaming device so that users can load unauthorised applications. Instead it deletes important system files and renders the device unbootable.

Security firm F-Secure has analysed and confirmed the report. Symantec refers to the exploit as Trojan.PSPBrick and labels it as a category 1 threat, the lowest level on its five-step scale as it does not spread to other devices. 

The file claims to be crafted by 'PSP Team', according to a report on the PSP Updates enthusiast website. 

Ever since Sony released the first version of the portable gaming device, the company has been trying to catch up with developers that use it for custom applications.

Sony designed the PSP for games, photos, music and internet browsing. Developers have added numerous applications that allow the device to display text files, for instance, or streaming music from the internet. 

The latest model ships with an upgraded version 2.0 of the firmware that blocks users from installing 'homebrew' applications.

But it was not long before developers discovered a buffer overflow vulnerability in the software that allowed them to install the previous 1.5 version.

Tools that made it easier to downgrade the firmware soon started circulating on the internet.

At the time of going to press Sony had not returned phone calls seeking further information.