Junglewise Threat Intelligence

CVE-2023-28746: Intel Atom Processors Register File Data Sampling Information Disclosure

CVE-2023-28746 · Severity: medium · CVSS 6.5 · Published 2024-03-14

Technologies: Xen Project Xen. Vendors: Intel, Xen Project.

Executive brief

A vulnerability in certain Intel Atom processors could allow a local user to access sensitive data they should not be able to see. This issue, known as Register File Data Sampling (RFDS), occurs when the processor fails to properly clear internal storage areas (registers) during specific operations. An attacker could potentially use this to steal information from other programs or more privileged parts of the operating system running on the same computer.

Technical details

Register File Data Sampling (RFDS) is a microarchitectural vulnerability (CWE-1342) affecting Intel Atom cores from the Goldmont to Gracemont microarchitectures. The flaw allows an attacker to infer the contents of data previously held in floating-point, vector, or integer register files on the same logical processor through transient execution side channels. While these processors do not support HyperThreading (reducing cross-thread exposure), data can still be leaked from more privileged contexts (e.g., kernel to user or guest to host). Mitigation requires both microcode updates from Intel—which extend the VERW instruction to scrub these register files—and operating system/hypervisor patches to correctly invoke these scrubbing mechanisms during context switches.

Affected products

  • Intel Atom Processors (Goldmont through Gracemont) Microarchitectures Goldmont through Gracemont, including Alder Lake and Raptor Lake hybrid systems
  • Xen Project Xen All versions

Timeline

  • 2024-03-12: disclosed: Intel and Xen Project disclosed RFDS details
  • 2024-03-14: advisory: NVD entry published
  • 2024-05-04: patched: Debian released updated intel-microcode packages

References

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