Written by James Orme Tue 4 Jun 2019

FPGA chips are generally considered secure, but a newly discovered vulnerability opens a gateway for side-channel attacks

Scientists have discovered a vulnerability in Field-programmable gate arrays (FPGAs) that might serve as a gateway for hackers to attack cloud services and IoT devices.

Unlike conventional computer chips that are built to perform one specific task, FPGAs are highly modifiable even after they are produced, often making them the first choice when developing new devices or systems. Experts expect the chips to address accelerating compute requirements in 5G, network function virtualization (NFV), automotive, industrial, and military/aerospace applications.

As they offer comparatively low power consumption compared to other processors, the major cloud providers, particularly Microsoft, stack their hyperscale data centres with FPGAs to power cloud services. For instance, FPGAs are considered more efficient and powerful than GPUs for running certain machine learning algorithms.

As the chips can also be partitioned between different users, they are particularly useful for cloud services involving databases, AI or financial application workloads.

The use of such services has not previously raised any red flags in cyber security, as FPGAs are generally considered secure. However, researchers at Karlsruhe Institute of Technology (KIT) have described a new vulnerability that enables hackers to execute side-channel attacks — whereby hackers exploit a chip’s energy consumption to retrieve decryption information.

In a press release, researchers Dennis Gnad and Jonas Krautter said the same multi-access versatility that makes FPGAs so popular in the data centre provides a gateway for clever hackers. As multiple cloud users can access the chips to track energy consumption, it is possible for a malicious customer to spy on another user and tamper with their energy calculations.

“It is possible to tamper with the calculations of other customers or even to crash the chip altogether, possibly resulting in data losses,” Krautter said.

Gnad and Krautter added that the vulnerability can be prevented if cloud providers restrict the immediate access of users to the FPGAs, but the side effect of this is that legitimate users will also be impacted.

“The challenge is to reliably filter out malicious users without tying up the legitimate ones too much,” Gnad said.