## Cryptology ePrint Archive: Report 2019/613

MeltdownDetector: A Runtime Approach for Detecting Meltdown Attacks

Taha Atahan Akyildiz and Can Berk Guzgeren and Cemal Yilmaz and Erkay Savas

Abstract: In this work, we present a runtime approach, called MeltdownDetector, for detecting, isolating, and preventing ongoing Meltdown attacks that operate by causing segmentation faults. Meltdown exploits a hardware vulnerability that allows a malicious process to access memory locations, which do not belong to the process, including the physical and kernel memory. The proposed approach is based on a simple observation that in order for a Meltdown attack to be successful, either a single byte of data located at a particular memory address or a sequence of consecutive memory addresses (i.e., sequence of bytes) need to be read, so that a meaningful piece of information can be extracted from the data leaked. MeltdownDetector, therefore, monitors segmentation faults occurring at memory addresses that are close to each other and issues a warning at runtime when these faults become suspicious.'' Furthermore, MeltdownDetector flushes the caches after every suspicious segmentation fault, preventing even a single byte of data from being leaked. In the experiments we carried out to evaluate the proposed approach, MeltdownDetector successfully detected all the attacks, correctly isolated all the malicious processes, and did so at the earliest possible time after the attacks have started with an average runtime overhead of 0.34% and without even leaking a single byte of information.

Category / Keywords: Meltdown; side-channel attacks; countermeasures; runtime detection, prevention, and isolation