Row Hammer: Flipping Bits in Memory Without Accessing Them - Papers We Love #026

Cool. So. I'm the second talk of the day.

And my talk is gonna be about

a paper with a pretty long title.

It's called Row Hammer

Flipping Bits in Memory

Without Accessing Them

colon, even more stuff.

And experimenting something

but that doesn't really matter.

So, my name is Vishnu

And I'm a year 4 Computer Science student

just like Chin.

and we are actually part of NUS Hackers.

It is a club/society in NUS.

This is my second time here.

I was here exactly 12 Papers We Love ago.

One year ago.

Audience: aww "Anniversary!"

... presenting the Diffie-Hellman Key Exchange

Which is also a security related paper

And today is another security related paper

Even though I have no academic experience

in security at all,

just seems to click with my interests.

So, the paper,

It's called... ah, colon... An Experimental Study of DRAM Disturbance Errors

This is a joint publication

by CMU and Intel Labs

The reason why it fascinated me so much is

We always talk about software exploits

as something to do with software.

It's a bug in software.

Either programmer made a mistake.

Or is usually a programmer made

a mistake somewhere

Or you forgot to check something.

But this is a hardware bug.

That affects software.

And that fascinated me.

A mistake in hardware,

or so-called mistake in hardware,

which you can not fix.

Because you can't patch hardware.

Is now affecting software forever.

And it's almost unpatchable.

Just because of the way hardware is.

Once you release hardware.

That's it.

So before we talk about

what this paper is about

let me just give you a brief history lesson

on what DRAM is.

DRAM stands for

Dynamic RAM

And that's the kind of RAM

that we have in all of our machines

Chinmay: Sorry, memory lane...

Thank you.

Yep, a lot of jokes like that

sprinkled inside this talk.

So DRAM stands for Dynamic RAM.

And it's the kind of RAM

that we have in every single machine

that we touch these days.

Previously in the 90s there was

a thing called SRAM

but it wasn't performing enough

so they made this thing called DRAM

for Dynamic RAM.

Here's an example of a kind of DRAM module

This is the Micron something

and this is a 1 MB chip.

So this entire chip holds exactly

1 megabyte of information

Which means that... one million...

Sorry...?

Rahul: RAM chips are normally sold

Rahul: in terms of bits.

Rahul: So when you say 1024

Rahul: that's 1024 megabit, usually.

Sorry, megabit. Which makes it 128 KB.

Sorry, you are right. it's actually 128 KB.

And, yea, so there's actually like

1 million dots in here.

If you count.

So each single dot here

Is called DRAM cell

And to understand the flaw here

We actually need to learn

exactly how a DRAM cell works.