In a presentation late yesterday during the Black Hat security conference in Las Vegas, a white-paper (PDF warning) of which has already been published, researcher Christopher Domas revealed what he describes as a 'This flaw, Domas explains, allows malicious code to jump from 'ring 0,' typically the most privileged level of execution, to 'ring -2,' the System Management Mode. While running under SMM, said code is able to preempt code running in any other ring, including the 'ring -1' hypervisor, and can even bypass protections such as Trusted Execution Technology. 'During the presentation, Domas revealed a working exploit - tested only on Intel processors, but believed effected on any x86 chips from the last couple of decades - which was able to jump code from ring 0 to ring -2. '' he explains. 'While Intel has not yet commented publicly on the flaw, Domas claims the company is aware of his research and has already worked to close the vulnerability in its latest processor designs. The company is also claimed to be releasing firmware updates for its older chips, but Domas has warned that not all processors can or will be patched to guard against the flaw. Thankfully, exploitation of the vulnerability requires low-level access to the host system - meaning that an attacker wishing to make use of the flaw to implant malicious code in ring -2 would already need to have ring 0 access, the highest level of access typically available to user-level code.Neither Intel nor AMD have released statements regarding Domas' findings.