Summary

This is a proof-of-concept exploit of the PortSmash microarchitecture attack, tracked by CVE-2018-5407.

Setup

Prerequisites

A CPU featuring SMT (e.g. Hyper-Threading) is the only requirement.

This exploit code should work out of the box on Skylake and Kaby Lake. For other SMT architectures, customizing the strategies and/or waiting times in 

 is likely needed.

OpenSSL

Download and install OpenSSL 1.1.0h or lower:

cd /usr/local/src

wget https://www.openssl.org/source/openssl-1.1.0h.tar.gz

tar xzf openssl-1.1.0h.tar.gz

cd openssl-1.1.0h/

export OPENSSL_ROOT_DIR=/usr/local/ssl

./config -d shared --prefix=$OPENSSL_ROOT_DIR --openssldir=$OPENSSL_ROOT_DIR -Wl,-rpath=$OPENSSL_ROOT_DIR/lib

make -j8

make test

sudo checkinstall --strip=no --stripso=no --pkgname=openssl-1.1.0h-debug --provides=openssl-1.1.0h-debug --default make install_sw

If you use a different path, you’ll need to make changes to 

 and 

.

Tooling

freq.sh

Turns off frequency scaling and TurboBoost.

sync.sh

Sync trace through pipes. It has two victims, one of which should be active at a time:

1. The stock 
   openssl

    running 

   dgst

    command to produce a P-384 signature.

2. A harness 
   ecc

    that calls scalar multiplication directly with a known key. (Useful for profiling.)

The script will generate a P-384 key pair in 

 if it does not already exist.

The script outputs 

 which is what 

 signed, and you should be able to verify the ECDSA signature 

 afterwards with

openssl dgst -sha512 -verify secp384r1.pem -signature data.sig data.bin

In the 

 tool case, 

 and 

 are meaningless and 

 is not created.

For the 

 commands in 

, the cores need to be two logical cores of the same physical core; sanity check with

$ grep '^core id' /proc/cpuinfo

core id     : 0

core id     : 1

core id     : 2

core id     : 3

core id     : 0

core id     : 1

core id     : 2

core id     : 3

So the script is currently configured for logical cores 3 and 7 that both map to physical core 3 (

).

spy

Measurement process that outputs measurements in 

. To change the 

 strategy, check the port defines in 

. Only one strategy should be active at build time.

Note that 

 is actually raw clock cycle counter values, not latencies. Look in 

 to understand the data format if necessary.

ecc

Victim harness for running OpenSSL scalar multiplication with known inputs. Example:

./ecc M 4 deadbeef0123456789abcdef00000000c0ff33

Will execute 4 consecutive calls to 

 with the given hex scalar.

parse_raw_simple.py

Quick and dirty hack to view 1D traces. The top plot is the raw trace. Everything below is a different digital filter of the raw trace for viewing purposes. Zoom and pan are your friends here.

You might have to adjust the 

 variable if the plots are too aggressively clipped.

Python packages:

sudo apt-get install python-numpy python-matplotlib

Usage

Turn off frequency scaling:

./freq.sh

Make sure everything builds:

make clean

make

Take a measurement:

./sync.sh

View the trace:

python parse_raw_simple.py timings.bin

You can play around with one victim at a time in 

. Sample output for the 

 victim is in 

.

Credits

• Alejandro Cabrera Aldaya (Universidad Tecnológica de la Habana (CUJAE), Habana, Cuba)
• Billy Bob Brumley (Tampere University of Technology, Tampere, Finland)
• Sohaib ul Hassan (Tampere University of Technology, Tampere, Finland)
• Cesar Pereida García (Tampere University of Technology, Tampere, Finland)
• Nicola Tuveri (Tampere University of Technology, Tampere, Finland)