Obviously, a compromise like this undermines the entire point of the trophy system. Sony's Eric Lempel explained to us that the PSP couldn't support trophies due to the unsecured nature of that platform. "If people can artificially inflate their rankings ... it kills the whole [Trophy] system," he explained. Unfortunately, it appears Sony now faces the same issue on the PS3.
"We are aware of this, and are currently looking into it," a SCEE representative commented. "We will fix the issues through network updates, but because this is a security issue, we are not able to provide you with any more details."
Source: CVG