x86 CPUs Found to Contain Hidden Hardware Backdoor
Original: Hardware backdoors in some x86 CPUs
Why This Matters
A hardware-level CPU backdoor bypassing OS privilege boundaries poses severe, patch-resistant security risks across affected systems.
Security researcher domas (@xoreaxeaxeax) has published 'project:rosenbridge,' revealing a hardware backdoor in certain x86 desktop, laptop, and embedded processors that allows userland (ring 3) code to bypass CPU protections and access kernel (ring 0) data.
The 'rosenbridge' project discloses a hardware backdoor embedded in some x86 CPUs, affecting desktop, laptop, and embedded systems. According to the researcher, the backdoor consists of a small, non-x86 core running alongside the main x86 core. It is controlled via a model-specific-register (MSR) bit and activated through a dedicated launch instruction. Once enabled, this embedded core accepts commands wrapped inside specially formatted x86 instructions and executes a 'deeply embedded instruction set' that bypasses all memory protections and privilege checks. While the backdoor normally requires ring 0 (kernel-level) access to activate, the researcher reports it is enabled by default on some systems — meaning userland code could potentially exploit it without elevated privileges. The GitHub repository includes utilities to detect whether a processor is affected, tools to close the backdoor if present, and the full research and analysis used to discover the vulnerability. The project has attracted significant attention, accumulating 2,500+ stars and 224 forks on GitHub.