Metior Framework Quantifies Side-Channel Attacks Vulnerability

Thursday - July 6 2023, 19:07 UTC - 1 year ago

MIT researchers created a framework called Metior to quantitatively evaluate how much information an attacker could learn from a victim program with an obfuscation scheme in place. The framework allows users to study how different victim programs, attacker strategies and obfuscation schemes configuration affects the amount of sensitive information that is leaked and can be used by engineers when designing microprocessors.

A savvy hacker can obtain secret information, such as a password, by observing a computer program's behavior, like how much time that program spends accessing the computer's memory.Security approaches that completely block these "side-channel attacks" are so computationally expensive that they aren't feasible for many real-world systems. Instead, engineers often apply what are known as obfuscation schemes that seek to limit, but not eliminate, an attacker's ability to learn secret information.

To help engineers and scientists better understand the effectiveness of different obfuscation schemes, MIT researchers created a framework to quantitatively evaluate how much information an attacker could learn from a victim program with an obfuscation scheme in place.

Their framework, called Metior, allows the user to study how different victim programs, attacker strategies, and obfuscation scheme configurations affect the amount of sensitive information that is leaked. The framework could be used by engineers who develop microprocessors to evaluate the effectiveness of multiple security schemes and determine which architecture is most promising early in the chip design process.

"Metior helps us recognize that we shouldn't look at these security schemes in isolation. It is very tempting to analyze the effectiveness of an obfuscation scheme for one particular victim, but this doesn't help us understand why these attacks work. Looking at things from a higher level gives us a more holistic picture of what is actually going on," says Peter Deutsch, a graduate student and lead author of an open-access paper on Metior.

Deutsch's co-authors include Weon Taek Na, an MIT graduate student in electrical engineering and computer science; Thomas Bourgeat Ph.D. '23, an assistant professor at the Swiss Federal Institute of Technology (EPFL); Joel Emer, an MIT professor of the practice in computer science and electrical engineering; and senior author Mengjia Yan, the Homer A. Burnell Career Development Assistant Professor of Electrical Engineering and Computer Science (EECS) at MIT and a member of the Computer Science and Artificial Intelligence Laboratory (CSAIL). The research was presented last week at the International Symposium on Computer Architecture in Orlando, Florida.

Illuminating obfuscation .

While there are many obfuscation schemes, popular approaches typically work by adding some randomization to the victim's behavior to make it harder for an attacker to learn secrets. For instance, perhaps an obfuscation scheme involves a program accessing additional areas of the computer memory, rather than only the area it needs to access, to confuse an attacker. Others adjust how often a victim accesses memory or another a shared resource so an attacker has trouble seeing clear patterns.

But while these approaches make it harder for an attacker to succeed, some amount of information from the victim still "leaks" out. Yan and her team want to know how much.

They had previously developed CaSA, a tool to quantify the amount of information leaked by one particular type of obfuscation scheme. But with Metior, they had more ambitious go to quantify how much information is revealed by a range of obfuscation approaches — in any context.