The hardware-based mitigations introduced in Intel and ARM CPUs over the past few years to fix a serious flaw called Spectre are not as strong as believed. Researchers have devised a new attack method that can defeat the defenses, but exploitation is not as easy as with the original flaw.The new attack, discovered by researchers from the Systems and Network Security Group at VU Amsterdam (VUSec) is called Spectre-BHI, for Branch History Injection, or Spectre-BHB, for Branch History Buffer, because Intel and ARM assigned different names to it.