Security experts at the Invisible Things lab have found a new vulnerability in certain Intel processors.

The SINIT feature of SMM (System Management Mode) can interfere with TXT (Trusted eXecution Technology), allowing it to elevate privileges, trick the SENTER instruction into not protecting a newly-loaded hypervisor or kernel. The upshot of one acronym influencing another is that rootkits can be developed which run at the most basic, privileged level of the processor.

Intel has put its hand up to the flaw and issued an advisory conceding the error and announcing a new SINIT ACM (Authenticated Code Module) to fix the problem. Systems with Q35, GM45, PM45 Express, Q45, and Q43 Express chipsets are affected.

It is the second TXT flaw found by Invisible Things Lab. A similar, but unrelated attack was disclosed by them and patched by Intel in February.