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microcode

3 articles · Page 1 of 1
Black & White Path
Black & White Path
Jun 6, 2026 · Information Security

The Secret CPU Instructions Intel, AMD and ARM Keep Hidden (And Why They Matter)

The article explores the origins of undocumented CPU instructions—from early transistor‑saving tricks like SALC and POP CS to modern hidden backdoors such as Intel’s undocumented RISC core and the udbgrd/udbgwr commands—explaining how researchers like 0day_ninja use the MystFuzz tool to discover and exploit these covert opcodes.

CPUMystFuzzhardware security
0 likes · 8 min read
The Secret CPU Instructions Intel, AMD and ARM Keep Hidden (And Why They Matter)
Open Source Linux
Open Source Linux
May 29, 2025 · Information Security

First CPU‑Level Ransomware Proof‑of‑Concept Revealed – Why It Matters

Rapid7’s Chrstiaan Beek has created the world’s first CPU‑level ransomware proof‑of‑concept, exploiting AMD Zen microcode vulnerabilities to hijack BIOS and encrypt drives, a technique that can bypass traditional detection and remain active even after OS reinstall, though he promises not to release it.

AMDCPU ransomwareRAPID7
0 likes · 3 min read
First CPU‑Level Ransomware Proof‑of‑Concept Revealed – Why It Matters