Los Angeles (CA) - Responding almost immediately to news of the discovery of a buffer overflow exploit in Sony's PlayStation Portable firmware version 2.0, enabling some homebrew code to run from memory stick without running a so-called "downgrader" first, Sony has released a version 2.01 patch that should disable the exploit.

Sony PlayStation officially acknowledged the exploit just yesterday.

News of the discovery of the buffer overflow was first reported on 24 September; and in the short intervening time, an entire cottage industry may have been born, nurtured, attacked, and squelched. Normally, the term "buffer overflow exploit" is associated with the creation of a virus. In this case, the concept was explored in order to make the PSP run ordinary programs, created not by software manufacturers but by individual experimenters and hobbyists. The products of their work are often not pirated programs, but programming experiments such as chess engines and emulators of older hardware. Up to now, many of these hobbyists had resisted upgrading to version 2.0, knowing that doing so would render their PSPs unable to perform the tricks they'd discovered to run their code from memory stick rather than UMD disc. By not upgrading, however, they wouldn't be able to take advantage of new PSP functionality, such as WiFi connectivity and the new built-in Web browser.

For perhaps the first time, the hobbyists themselves found themselves the victim of malicious software attacks. When the exploit was discovered, hopes were raised that it could be used to deliver the long-awaited "holy grail" of homebrew development, the version 2.0 downgrader. Such a program would be capable of replacing the 2.0 firmware image inside the PSP's internal flash memory, with a complete older image - assuming the user has made a legal copy of that image. Why would one want to do this? To re-enable homebrew functionality under an older firmware version, even if only to replace it later with 2.0...and go back and forth at will. It could also enable newly purchased PSPs to be adapted to run homebrew software.

Capitalizing on all the excitement, however, a malicious developer released a false downgrader program, reportedly through Usenet, which also takes advantage of the exploit, but which instead reportedly irreversibly destroyed the PSP's firmware when run.

So Tuesday morning, a developer with the sig "Dark Killer" released what could very well be the PSP's first anti-malware utility, called PSafeP. It's actually a Windows program which scans the code of downloaded archive files before they're transferred to memory stick, looking for and identifying instructions which attempt to make direct access to flash memory. Of course, this program could conceivably identify any downgrader as potentially malicious, although it should certainly point out any homebrew program that passes itself off as completely benign, but isn't.

Just before PSafeP's release, a presumably legitimate program called the MPH Downgrader was released to PSP homebrew Web sites. Not long afterward (which is the general interval of time between generational events in the PSP world), one homebrew site posted a video demonstrating how users can downgrade version 2.0 PSPs to version 1.5, partly set to the tune of the Jedi theme from "Star Wars." The downgrader should not be functional, or should not be tried, with version 2.01 firmware. At this point, Sony might want us to mention that following the instructions depicted in this video will likely invalidate your PSP's warranty.

Source : Tom's Hardware US