From bitdefender.com
Bitdefender researchers have identified and demonstrated a new side-channel attack. The attack builds on previous research which led to the Spectre and Meltdown attacks. This newly disclosed attack bypasses all known mitigation mechanisms implemented in response to Spectre and Meltdown. Bitdefender Hypervisor Introspection renders Windows systems impervious to this new attack.
The SWAPGS Attack affects newer Intel CPUs that use speculative execution.
In pursuit of ever-faster CPUs, vendors have implemented various versions of speculative execution. This functionality has the CPU making educated guesses about instructions that may be required before it determines whether the instructions are, in fact, required. This speculative execution may leave traces in cache that attackers can use to leak privileged, kernel memory.
This attack takes advantage of a combination of Intel speculative execution of a specific instruction (SWAPGS) and use of that instruction by Windows operating systems within what is known as a gadget.