# UNFINISHED ARTICLE — UNDER CONSTRUCTION — BAD FORMATTING

# AMD CPU Family

Advanced Micro Devices, Inc. is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. This article is specifically about the CPUs that are produced by AMD and nothing else. The logo is one of many logos used by AMD, but the article is not about any one specific CPU. No rating is given because this is not an article about any specific product, and the rating system is difficult to fit into this article.

Modern CPU models produced by AMD contain an embedded ARM co-processor called the Platform Security Processor (PSP). Nearly all AMD CPUs produced since 2013 operate under the supervision of this separate, more privileged, environment consisting of an integrated ARM processor with access to isolated resources as well as main system memory and I/O. [1]

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http://www.uefi.org/sites/default/files/resources/UEFI_PlugFest_AMD_Security_and_Server_innovation_AMD_March_2013.pdf (page 11)

While ARM and AMD tout the “Trusted Execution Environment” as useful for secure payment, anti-theft and malware protection, they also discuss content protection or DRM as a use case. https://www.owasp.o../images/c/c8/OWASP_Security_Tapas_-_TrustZone%2C_TEE_and_Mobile_Security_final.pdf

Possible uses … DRM

Researchers have already been able to identify exploits in AMD’s Platform Security Processor. In 2018 researchers published a vulnerability in which a specially crafted certificate could lead to a stack overflow in the PSP’s TPM firmware allowing for remote code execution. (https://seclists.org/fulldisclosure/2018/Jan/12) Another group goes on to detail how an attacker might leverage exploits RYZENFALL or FALLOUT to gain foothold in networks with Ryzen based systems. (https://www.techpowerup.com/242386/cts-labs-responds-to-a-techpowerup-technical-questionnaire)

Please note that Family 16h and Family 15h-Models60h and later contain a PSP

## NOT TRUSTED:

- Kaveri (Steamroller “BDv3”) https://www.amd.com/system/files/TechDocs/51590_15h_Models_30h-3Fh_A-Series_PDS.pdf (page 6) https://arstechnica.com/information-technology/2012/06/amd-to-add-arm-processors-to-boost-chip-security/
- Carrizo/Bristol Ridge (Excavator “BDv4”) https://www.anandtech.com/show/8995/amd-at-isscc-2015-carrizo-and-excavator-details
- All Zen based CPUs (17h family)

## POTENTIALLY TRUSTED:

- Jaguar (the only 16h family CPU that does NOT have PSP): http://support.amd.com/TechDocs/52128_16h_Software_Opt_Guide.zip (page 8) https://en.wikipedia.org/wiki/Puma_(microarchitecture)#Improvements_over_Jaguar
- All K5-K10, Bobcat, Bulldozer (“BDv1”) and Piledriver (“BDv2”)
- All K5-K10, Bobcat, Bulldozer (“BDv1”) and Piledriver (“BDv2”)