CyberSecBulletin
CVE-2023-20529NVD status: Modified

2nd Gen EPYC: Improper Restriction of Operations within the Bounds of a Memory Buffer

Published Updated By the CyberSecBulletin desk

CVE-2023-20529 is a high-severity improper restriction of operations within the bounds of a memory buffer vulnerability in 2nd Gen EPYC from AMD, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected 2nd Gen EPYC versions: various. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Epyc 7h12 Firmware to romepi_1.0.0.c or a later version.
  2. Update Epyc 7f72 Firmware to romepi_1.0.0.c or a later version.
  3. Update Epyc 7f52 Firmware to romepi_1.0.0.c or a later version.
  4. Read the advisory on amd.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
AMD2nd Gen EPYCvariousNot stated
AMD3rd Gen EPYCvariousNot stated
AMDEpyc 7h12 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7f72 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7f52 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7f32 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7742 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7702p Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7702 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7662 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7642 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7552 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7542 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7532 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7502p Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7502 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7452 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7402 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7402p Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7352 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7302p Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7302 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7282 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7272 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c
AMDEpyc 7262 Firmwarebefore romepi_1.0.0.cromepi_1.0.0.c

Version data comes from the organisation that assigned the CVE; 27 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.5HighNVD
CVSS 3.17.5HighCISA (ADP)

Official description

Insufficient bound checks in the SMU may allow an attacker to update the from/to address space to an invalid value potentially resulting in a denial of service.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities (CWE-119)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in 2nd Gen EPYC

All 2nd Gen EPYC vulnerabilities

Recent Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities

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