Table Of Links
Abstract
1. Introduction
2. Background
- Memory Tagging Extension
- Speculative Execution Attack
3. Threat Model
4. Finding Tag Leakage Gadgets
- Tag Leakage Template
- Tag Leakage Fuzzing
5. TIKTAG Gadgets
- TIKTAG-v1: Exploiting Speculation Shrinkage
- TIKTAG-v2: Exploiting Store-to-Load Forwarding
6. Real-World Attacks
6.1. Attacking Chrome
7. Evaluation
8. Related work
9. Conclusion And References
Related work
MTE Security Analysis. Partap et al. [51] analyzed the software-level MTE support in real-world memory allocators. Google Project Zero [38] explored speculative execution attacks against MTE hardware for the first time. StickyTags [22] identified an MTE tag leakage gadget (which is similar to TIKTAG-v1) and proposed a deterministic tagging-based defense that does not utilize random tags due to the potential tag leakage. Compared to StickyTags, our work identified a new type of MTE tag leakage gadget, TIKTAG-v2, and analyzed the root cause of both TIKTAG-v1 and TIKTAG-v2 gadgets.
We also demonstrated the realworld exploitation of TIKTAG gadgets in Google Chrome and the Linux kernel and proposed new defense mechanisms to mitigate the security risks posed by TIKTAG gadgets. While StickyTags proposed deterministic tagging due to the potential tag leakage, our work focuses on hardening the random tagging-based MTE defense, which are developed by major vendors including Google [39], the Linux kernel [26], and secure operating systems [23, 50, 63].
Speculative Attacks on Protection Mechanisms. Speculative probing [20] suggested that speculative execution can be used to probe address mappings and bypass address space layout randomization (ASLR). PACMAN [54] identified speculative gadgets that leak Pointer Authentication Code (PAC). ARMv8.6 FEAT_FPAC mitigates PACMAN attacks by authentication and memory access, allowing all memory accesses regardless of the authentication result [35]. MTE tag leakage can also be mitigated by separating tag check and memory access in the hardware, not allowing tag check results to affect memory access.
Transient Execution Attacks. Transient execution attacks exploit micro-architectural behaviors to leak secret information. Researchers have analyzed various micro-architectural implementations including speculative execution [30, 36, 66, 71], memory disambiguation prediction [24, 41, 45], and CPU internal buffers [67, 68]. Recent attacks exploited data prefetching behaviors to leak secret information or construct covert channels [14, 57, 59, 69]. Compared to these attacks, we identified for the first time that data prefetching behaviors can also be exploited to leak hardware exceptions, such as tag check faults (§5.1).
9. Conclusion
This paper explores the potential security risks posed by speculative execution attacks against ARM Memory Tagging Extension (MTE). We identify new MTE oracles, TIKTAG-v1 and TIKTAG v2, capable of leaking MTE tags from arbitrary memory addresses. TIKTAG gadgets can bypass MTE-based defense in real-world systems, including Google Chrome and the Linux kernel. Our findings provide significant insights into the design and deployment of both memory taggingbased hardware and software defenses.
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:::info
Authors:
- Juhee Kim
- Jinbum Park
- Sihyeon Roh
- Jaeyoung Chung
- Youngjoo Lee
- Taesoo Kim
- Byoungyoung Lee
:::
:::info
This paper is available on arxiv under CC 4.0 license.
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