Special Register Buffer Data Sampling Advisory
A potential security vulnerability in some Intel® Processors may allow information disclosure. Intel is releasing firmware updates to mitigate this potential vulnerability.
Description: Incomplete cleanup from specific special register read operations in some Intel(R) Processors may allow an authenticated user to potentially enable information disclosure via local access.
CVSS Base Score: 6.5 Medium
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
A list of impacted products can be found here.
Intel recommends that users of affected Intel® Processors update to the latest version firmware provided by the system manufacturer that addresses this issue.
Intel has released microcode updates for the affected Intel® Processors that are currently supported on the public github repository. Please see details below on access to the microcode:
GitHub*: Public Github: https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files
The microcode updates also provide an opt-out mechanism (RNGDS_MITG_DIS) to disable the mitigation for RDRAND and RDSEED instructions executed outside of Intel® Software Guard Extensions (Intel® SGX) enclaves. Please refer to technical details to find additional information on the opt-out mechanism here.
Note that inside of an Intel SGX enclave, the mitigation is applied regardless of the value of RNGDS_MITG_DIS.
Additional technical details about SRBDS can be found here.
To address this issue, an SGX TCB recovery will be required in Q3 2020. Refer to Intel® SGX Attestation Technical Details for more information on the SGX TCB recovery process.
Intel would like to thank Alyssa Milburn, Hany Ragab, Kaveh Razavi, Herbert Bos, Cristiano Giuffrida from the VUSec group at VU Amsterdam for reporting this issue.
This issue was also identified by Intel employees. Intel would like to thank Rodrigo Branco (formerly Intel), Kekai Hu (formerly Intel), Gabriel Negreira Barbosa (Intel), and Ke Sun (Intel).
Intel, and nearly the entire technology industry, follows a disclosure practice called Coordinated Disclosure, under which a cybersecurity vulnerability is generally publicly disclosed only after mitigations are available.
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