ARMageddon: Cache Attacks on Mobile Devices

TL;DR

This paper demonstrates novel cross-core cache attacks on non-rooted Android smartphones with ARM CPUs, enabling covert channels and monitoring sensitive user activities, including cryptographic operations, across millions of devices.

Contribution

It introduces techniques to perform powerful cache attacks on ARM-based smartphones without privileges, addressing key challenges and enabling new attack vectors.

Findings

Successfully performed cross-core cache attacks on non-rooted Android devices

Achieved covert channels outperforming previous methods on Android

Monitored user interactions and cryptographic primitives in Java

Abstract

In the last 10 years, cache attacks on Intel x86 CPUs have gained increasing attention among the scientific community and powerful techniques to exploit cache side channels have been developed. However, modern smartphones use one or more multi-core ARM CPUs that have a different cache organization and instruction set than Intel x86 CPUs. So far, no cross-core cache attacks have been demonstrated on non-rooted Android smartphones. In this work, we demonstrate how to solve key challenges to perform the most powerful cross-core cache attacks Prime+Probe, Flush+Reload, Evict+Reload, and Flush+Flush on non-rooted ARM-based devices without any privileges. Based on our techniques, we demonstrate covert channels that outperform state-of-the-art covert channels on Android by several orders of magnitude. Moreover, we present attacks to monitor tap and swipe events as well as keystrokes, and even derive the lengths of words entered on the touchscreen. Eventually, we are the first to attack cryptographic primitives implemented in Java. Our attacks work across CPUs and can even monitor cache activity in the ARM TrustZone from the normal world. The techniques we present can be used to attack hundreds of millions of Android devices.