ARM Memory Tagging Extension (MTE) is a new hardware feature introduced in ARMv8.5-A architecture, aiming to detect memory corruption vulnerabilities. The low overhead of MTE makes it an attractive solution to mitigate memory corruption attacks in modern software systems and is considered the most promising path forward for improving C/C++ software security. This paper explores the potential security risks posed by speculative execution attacks against MTE. Specifically, this paper identifies new Tiktag gadgets capable of leaking the MTE tags from arbitrary memory addresses through speculative execution. With Tiktag gadgets, attackers can bypass the probabilistic defense of MTE, increasing the attack success rate by close to 100%. We demonstrate that Tiktag gadgets can be used to bypass MTE-based mitigations in real-world systems, Google Chrome and the Linux kernel. Experimental results show that Tiktag gadgets can successfully leak an MTE tag with a success rate higher than 95% in less than 4 seconds. We further propose new defense mechanisms to mitigate the security risks posed by Tiktag gadgets.

Data-only attacks are emerging as a new threat to the security of modern operating systems. As a typical data-only attack, memory corruption attacks can compromise the integrity of kernel data, which effectively breaks the premises of access control systems. Unfortunately, the prevalence of memory corruption vulnerabilities allows attackers to exploit them and bypass access control mechanisms. Given the arbitrary memory access capability, attackers can overwrite access control policies or illegally access the kernel resources protected by the access control systems.

Temporal memory safety violations, such as use-after-free (UAF) vulnerabilities, are a critical security issue for software written in memory-unsafe languages such as C and C++.

Cache side-channel attacks abuse microarchitectural designs meant to optimize memory access to infer information about victim processes, threatening data privacy and security. Recently, the ARM architecture has come into the spotlight of cache side-channel attacks with its unprecedented growth in the market.

The security of ARM TrustZone relies on the idea of splitting system-on-chip hardware and software into two worlds, namely normal world and secure world. In this paper, we report cross-world covert channels, which exploit the world-shared cache in the TrustZone architecture. We design a Prime+Count technique that only cares about how many cache sets or lines have been occupied. The coarser-grained approach significantly reduces the noise introduced by the pseudo-random replacement policy and world switching. Using our Prime+Count technique, we build covert channels in single-core and cross-core scenarios in the TrustZone architecture. Our results demonstrate that Prime+Count is an effective technique for enabling cross-world covert channels on ARM TrustZone.