@Rayiizzz

Microarchitectural Security | PhD Candidate at CISPA | Ex Research Intern @Google | #StackWarp #CacheWarp

zhangruiyi.me/
Joined August 2019
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5Media
Today we reveal StackWarp: a new CPU vulnerability exploiting a synchronization bug in AMD’s stack engine across Zen 1–5 CPUs. It enables deterministic manipulation of Confidential VM's stack pointer, allowing RCE and privilege escalation via both control- and data-flow hijacking
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Ruiyi Zhang retweeted
Michael Schwarz@misc0110Jul 28
The uASC'27 submission deadline has been extended by one week to August 4, 2026. We welcome work on all aspects of microarchitectural security, including attacks, defenses, analysis, and hardware-software interactions. uasc.cc/ #uASC #Microarchitecture
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Daniel Weber@weber_danielApr 17
After an embargo of 256 days, I'm happy to reveal our newest work: we present TREVEX, a black-box CPU fuzzer that detects transient execution vulnerabilities in an automated manner. Running TREVEX on AMD, Intel, and Zhaoxin CPUs discovered multiple new CPU vulnerabilities!
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HOSEIN YAVARZADEH@hosein_yzApr 2
Private AI in Confidential VMs isn't as private as we thought. 🤯 We just showed how to reconstruct user LLM prompts word-for-word from inside an encrypted Intel TDX enclave—without breaking any cryptography. Introducing TDXRay (IEEE S&P 2026): tdxray.cpusec.org/ (1/4)
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To clear up some confusion: the root cause lies in the stack engine, a CPU frontend optimization that manages the Stack Pointer (RSP) to reduce backend overhead. We discovered that an undocumented MSR bit acts as a toggle for this optimization. (1/2)
Ruiyi Zhang@RayiizzzJan 15
Today we reveal StackWarp: a new CPU vulnerability exploiting a synchronization bug in AMD’s stack engine across Zen 1–5 CPUs. It enables deterministic manipulation of Confidential VM's stack pointer, allowing RCE and privilege escalation via both control- and data-flow hijacking
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If an SMT sibling disables it, the RSP delta becomes 'frozen' and is only released to a future execution context when the bit is toggled again. While the underlying bug exists across Zen 1-5, it only poses a security risk in specific scenarios, like within confidential computing.
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SecurityWeek
@SecurityWeekJan 15
New StackWarp Attack Threatens Confidential VMs on AMD Processors securityweek.com/new-stackwa…

New ‘StackWarp’ Attack Threatens Confidential VMs on AMD Processors

Researchers have disclosed technical details on a new AMD processor attack that allows remote code execution inside confidential VMs.

securityweek.com
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For more details on the discovery process and our findings, we refer to our research paper, which is published at USENIX Security 2026. paper: stackwarpattack.com/ github: github.com/cispa/StackWarp \cc Tristan Hornetz, @weber_daniel, @fth0mas, @misc0110
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Blogpost: roots.ec/blog/stackwarp/

StackWarp: Exploiting Stack Layout Vulnerabilities in Modern Processors | Rootsec

We are disclosing a novel CPU bug affecting AMD Zen 1-5 microarchitectures.

roots.ec
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Kav@kavehrazaviJan 12
The program for uASC'26 is online uasc.cc/program.html We have some very interesting papers which are already available, so be sure to check them out. Better yet, join us in Leuven next month to listen to the authors! Registration is still open and free but seats are limited.
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🔓 Heracles @acm_ccs'25: Breaking AMD’s Confidential Computing! We show that the hypervisor can read and move hardware-encrypted memory on AMD SEV-SNP. We build a chosen-plaintext oracle to leak kernel memory, auth keys, and cookies from "confidential" VMs heracles-attack.github.io/

Heracles Attack

Breaking AMDs confidential computing solution using a Chosen Plaintext Attack

heracles-attack.github.io
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Kav@kavehrazavi20 May 2025
I am chairing the second edition of the microarchitecture security conference (uASC'26). Paper deadline for the first cycle is July 15. Please spread the word, submit, and/or join us in charming Leuven in February 2026! More info: uasc.cc
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Kav@kavehrazavi13 May 2025
long embargo, but there is a demo with good music at least: youtu.be/jrsOvaN7PaA
Sandro@sparchatus13 May 2025
Disclosing Branch Predictor Race Conditions (BPRC), a new class of vulnerabilities where asynchronous branch predictor operations violate hardware-enforced privilege and context separation in virtually all recent Intel CPUs. @wiknerj @kavehrazavi : comsec.ethz.ch/bprc
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✅ Write constant-time crypto code ☠️ Compiler introduces timing side-channels Do Compilers Break Constant-time Guarantees? fc25.ifca.ai/preproceedings/… TL;DR: Yes!🥲 👏👏👏Great work @misc0110 & team!
oh yeah, oh no meme. oh yeah: "Implementing constant-time crypto algorithm." oh no: "Compiler introduces timing side-channels."

ALT oh yeah, oh no meme. oh yeah: "Implementing constant-time crypto algorithm." oh no: "Compiler introduces timing side-channels."

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github.com/google/security-r… Our newest research project is finally public! We can load malicious microcode on Zen1-Zen4 CPUs!

AMD: Microcode Signature Verification Vulnerability

### Summary Google Security Team has identified a security vulnerability in some AMD Zen-based CPUs. This vulnerability allows an adversary with local administrator privileges (ring 0 from outside...

github.com
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Super excited to present our (L. Niemann, @____salmon____, @jan__reineke, @misc0110) newest paper at #ACSAC2024! We show how modern CPU hardware can be leveraged to stop side-channel attacks almost instantly (~200 CPU cycles)! Code/Paper: github.com/cispa/IRQGuard
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Excited to announce the release of the Rapid Data Analysis (RDA) framework! RDA streamlines side-channel analysis with plotting, processing, and analysis tools—usable directly from the terminal or in scripts. Check it out: github.com/0xhilbert/rda #SideChannel
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🤔 Want to know how we developed a hardware fuzzer that found the GhostWrite vulnerability? 🔓 This critical hardware flaw bypasses all security isolations on affected CPUs, raising serious concerns for security. 👉 hardwear.io/netherlands-2024… #rowhammer #hardware #hw_ioNL2024
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Congratulations Andi! It's been awesome working with you. Good luck with everything ahead!
Andreas Kogler@0xhilbert25 Aug 2024
I defended my PhD with distinction at @tugraz last friday! 🎉 Thank you to all the friends and folks who made this journey unforgettable. Special shoutout to @lavados, who went above and beyond by designing a game based on a "beer"-idea: Werewolves in the context of academia 🐺🎓
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First week as a Research Intern at @Google! Excited to dive into cutting-edge research and solve real-world problems.
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