AMD Server Vulnerabilities - May 2022
Bulletin ID: AMD-SB-1028
Potential Impact: Varies by CVE, see descriptions below
Severity: Varies by CVE, see descriptions below
Summary
During security reviews in collaboration with Google, Microsoft, and Oracle, potential vulnerabilities in the AMD Secure Processor (ASP), AMD System Management Unit (SMU), AMD Secure Encrypted Virtualization (SEV), and other platform components were discovered and have been mitigated in AMD EPYC™ AGESA™ PI packages.
CVE Details
Refer to Glossary for explanation of terms
CVE |
CVSS Score |
CVE Description |
|
7.2 (High) |
Insufficient bound checks in the System Management Unit (SMU) may result in a system voltage malfunction that could result in denial of resources and/or possibly denial of service. |
CVE-2021-26347 |
6.1 (Medium) |
TOCTOU (time-of-check to time-of-use) issue in the System Management Unit (SMU) may result in a DMA (Direct Memory Access) to invalid DRAM address that could result in denial of service. |
CVE-2021-26376 |
6.1 (Medium) |
Insufficient checks in System Management Unit (SMU) FeatureConfig may result in reenabling features potentially resulting in denial of resources and/or denial of service. |
CVE-2021-26375 |
6.1 (Medium) |
Insufficient General Purpose IO (GPIO) bounds check in System Management Unit (SMU) may result in access/updates from/to invalid address space that could result in denial of service. |
CVE-2021-26378 |
6.1 (Medium) |
Insufficient bound checks in the System Management Unit (SMU) may result in access to an invalid address space that could result in denial of service. |
CVE-2021-26372 |
6.1 (Medium) |
Insufficient bound checks related to PCIE in the System Management Unit (SMU) may result in access to an invalid address space that could result in denial of service. |
CVE-2021-26339 |
5.5 (Medium) |
A bug in AMD CPU’s core logic may allow for an attacker, using specific code from an unprivileged VM, to trigger a CPU core hang resulting in a potential denial of service. AMD believes the specific code includes a specific x86 instruction sequence that would not be generated by compilers. |
CVE-2021-26348 |
4.7 (Medium) |
Failure to flush the Translation Lookaside Buffer (TLB) of the I/O memory management unit (IOMMU) may lead an IO device to write to memory it should not be able to access, resulting in a potential loss of integrity. |
CVE-2021-26342 |
4.1 (Medium) |
In SEV guest VMs, the CPU may fail to flush the Translation Lookaside Buffer (TLB) following a particular sequence of operations that includes creation of a new virtual machine control block (VMCB). The failure to flush the TLB may cause the microcode to use stale TLB translations which may allow for disclosure of SEV guest memory contents. Users of SEV-ES/SEV-SNP guest VMs are not impacted by this vulnerability. |
CVE-2021-26388 |
4.1 (Medium) |
Improper validation of the BIOS directory may allow for searches to read beyond the directory table copy in RAM, exposing out-of-bounds memory contents, resulting in a potential denial of service. |
CVE-2021-26349 |
4.1 (Medium) |
Failure to assign a new report ID to an imported guest may potentially result in an SEV-SNP guest VM being tricked into trusting a dishonest Migration Agent (MA). |
CVE-2021-26364 |
4.1 (Medium) |
Insufficient bounds checking in an SMU mailbox register could allow an attacker to potentially read outside of the SRAM address range which could result in an exception-handling leading to a potential denial of service. |
CVE-2021-26312 |
4.1 (Medium) |
Improper ECC (error correction code) protections implemented in ASP hardware may allow side-channel exposure potentially resulting in information disclosure. |
CVE-2021-26350 |
3.9 ( Low) |
A TOCTOU race condition in SMU may allow for the caller to obtain and manipulate the address of a message port register which may result in a potential denial of service. |
Affected Products
CVE |
1st Gen AMD EPYC™ |
2nd Gen AMD EPYC™ |
3rd Gen AMD EPYC™ |
CVE-2021-26373 |
● |
● |
● |
CVE-2021-26347 |
NA |
● |
● |
CVE-2021-26376 |
NA |
● |
● |
CVE-2021-26375 |
NA |
● |
● |
CVE-2021-26378 |
NA |
● |
● |
CVE-2021-26372 |
NA |
● |
● |
CVE-2021-26339 |
NA |
NA |
● |
CVE-2021-26348 |
NA |
NA |
● |
CVE-2021-26342 |
● |
NA |
● |
CVE-2021-26388 |
NA |
● |
● |
CVE-2021-26349 |
NA |
NA |
● |
CVE-2021-26364 |
NA |
● |
● |
CVE-2021-26312 |
● |
● |
● |
CVE-2021-26350 |
NA |
● |
● |
Mitigation
The AGESA™ versions listed below have been released to the Original Equipment Manufacturers (OEM) to mitigate these issues. Please refer to your OEM for the BIOS update specific to your product.
Platform |
AGESA Version |
Release Date |
1st Gen AMD EPYC |
NaplesPI-SP3_1.0.0.H |
12/14/2021 |
2nd Gen AMD EPYC |
RomePI-SP3_1.0.0.D |
12/16/2021 |
3rd Gen AMD EPYC |
MilanPI-SP3_1.0.0.7 |
11/11/2021 |
Acknowledgement
AMD thanks the following for reporting these issues and engaging in coordinated vulnerability disclosure.
- Reported by Shawn Hoffman (Microsoft Offensive Security Research): CVE-2021-26347, CVE-2021-26350, CVE-2021-26372, CVE-2021-26373, CVE-2021-26375, CVE-2021-26376, CVE-2021-26378
- Reported by Cfir Cohen, Jann Horn, Mark Brand of Google: CVE-2021-26348, CVE-2021-26349, CVE-2021-26312
- Found by “Silifuzz (Google)”: CVE-2021-26339
- Internally reported: CVE-2021-26342, CVE-2021-26364, CVE-2021-26388
Revisions
Revision Date |
Description |
05/10/2022 |
Initial publication |
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