On March 12, 2018, AMD received a communication from CTS Labs regarding research into security vulnerabilities involving some AMD products. Less than 24 hours later, the research firm went public with its findings.
Security and protecting users’ data is of the utmost importance to us at AMD and we have worked rapidly to assess this security research and develop mitigation plans where needed. This is our first public update on this research, and will cover both our technical assessment of the issues as well as planned mitigation actions.
The security issues identified by the third-party researchers are not related to the AMD “Zen” CPU architecture or the Google Project Zero exploits made public Jan. 3, 2018. Instead, these issues are associated with the firmware managing the embedded security control processor in some of our products (AMD Secure Processor) and the chipset used in some socket AM4 and socket TR4 desktop platforms supporting AMD processors. As described in more detail below, AMD has rapidly completed its assessment and is in the process of developing and staging the deployment of mitigations.
It’s important to note that all the issues raised in the research require administrative access to the system, a type of access that effectively grants the user unrestricted access to the system and the right to delete, create or modify any of the folders or files on the computer, as well as change any settings. Any attacker gaining unauthorized administrative access would have a wide range of attacks at their disposal well beyond the exploits identified in this research. Further, all modern operating systems and enterprise-quality hypervisors today have many effective security controls, such as Microsoft Windows Credential Guard in the Windows environment, in place to prevent unauthorized administrative access that would need to be overcome in order to affect these security issues. A useful clarification of the difficulties associated with successfully exploiting these issues can be found in this posting from Trail of Bits, an independent security research firm who were contracted by the third-party researchers to verify their findings.
The security issues identified can be grouped into three major categories. The table below describes the categories, the AMD assessment of impact, and planned actions.
|
Vulnerability Groups |
Problem Description & Method of Exploitation |
Potential Impact |
Planned AMD Mitigation |
|
MASTERKEY and PSP Privilege Escalation (AMD Secure Processor or “PSP” firmware) |
Issue: Attacker who already has compromised the security of a system updates flash to corrupt its contents. AMD Secure Processor (PSP) checks do not detect the corruption.
Method: Attacker requires Administrative access |
Attacker can circumvent platform security controls. These changes are persistent following a system reboot. |
Firmware patch release through BIOS update. No performance impact is expected.
AMD is working on PSP firmware updates that we plan to release in the coming weeks. |
|
RYZENFALL and FALLOUT
(AMD Secure Processor firmware) |
Issue: Attacker who already has compromised the security of a system writes to AMD Secure Processor registers to exploit vulnerabilities in the interface between x86 and AMD Secure Processor (PSP).
Method: Attacker requires Administrative access. |
Attacker can circumvent platform security controls but is not persistent across reboots.
Attacker may install difficult to detect malware in SMM (x86). |
Firmware patch release through BIOS update. No performance impact is expected.
AMD is working on PSP firmware updates that we plan to release in the coming weeks. |
|
“Promotory” |
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|
CHIMERA “Promontory” chipset used in many socket AM4 desktop and socket TR4 high-end desktop (HEDT) platforms. AMD EPYC server platforms, EPYC and Ryzen Embedded platforms, and AMD Ryzen Mobile FP5 platforms do not use the “Promontory” chipset. |
Issue: Attacker who already has compromised the security of a system installs a malicious driver that exposes certain Promontory functions.
Method: Attacker requires Administrative access. |
Attacker accesses physical memory through the chipset.
Attacker installs difficult to detect malware in the chipset but is not persistent across reboots. |
Mitigating patches released through BIOS update. No performance impact is expected.
AMD is working with the third-party provider that designed and manufactured the “Promontory” chipset on appropriate mitigations. |
AMD will provide additional updates on both our analysis of these issues and the related mitigation plans in the coming weeks.
