You're listening to the CyberWire's research Saturday.

I'm Dave Bitner and this is our weekly conversation with researchers and analysts tracking down the threats

and vulnerabilities, solving some of the hard problems and protecting ourselves in a rapidly

evolving cyberspace.

Thanks for joining us.

Last year we published a paper called Half and Half, where the rumors engineered the intricate

details of the branch predictor within a modern Intel processors.

That's Hossain Yavazarday, a PhD student at the University of California, San Diego.

Today we're discussing his work on Pathfinder, High Resolution Control flow attacks exploiting the conditional branch predictor.

So for example, as you know the vendors like Intel

AMD etc are very secretive about their branch predictor and all the other macro predictor

optimization. So what we did in our previous research was to find out like how is

this branch prediction mechanism implemented in modern Intel processor?

So we reverse engineered every single detail of the branch predictor in our previous research and building upon that we ended up doing some side channel

attacks on the branch predictor. So yeah it started from our previous research

gotcha well for folks who aren't familiar with it can you describe to us what exactly is the function of the branch predictor in a modern processor?

Yeah, so in computer architecture and computer systems, a branch predictor is a vital optimization to the CPU to the processor that tries to guess like which way a

branch will go for example think about and think about an if then else's structure.

So it guesses which way a single branch,

for example, if a statement focal,

will it be taken or not taken before this is known definitely so the purpose

of the branch predictor is to sort of improve the flow of the instructions

...