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CVE Vulnerabilities

CVE-2023-40550

Out-of-bounds Read

Published: Jan 29, 2024 | Modified: Nov 21, 2024
CVSS 3.x
5.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 2.x
RedHat/V2
RedHat/V3
5.5 MODERATE
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Ubuntu
MEDIUM
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Additional information
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2023-40550
CWEhttps://cwe.mitre.org/data/definitions/125.html

An out-of-bounds read flaw was found in Shim when it tried to validate the SBAT information. This issue may expose sensitive data during the systems boot phase.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

NameVendorStart VersionEnd Version
ShimRedhat*15.8 (excluding)
Red Hat Enterprise Linux 7RedHatshim-0:15.8-3.el7*
Red Hat Enterprise Linux 7RedHatshim-signed-0:15.8-1.el7*
Red Hat Enterprise Linux 8RedHatshim-0:15.8-4.el8_9*
Red Hat Enterprise Linux 8.2 Advanced Update SupportRedHatshim-0:15.8-2.el8_2*
Red Hat Enterprise Linux 8.2 Telecommunications Update ServiceRedHatshim-0:15.8-2.el8_2*
Red Hat Enterprise Linux 8.2 Update Services for SAP SolutionsRedHatshim-0:15.8-2.el8_2*
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportRedHatshim-0:15.8-2.el8_4*
Red Hat Enterprise Linux 8.4 Telecommunications Update ServiceRedHatshim-0:15.8-2.el8_4*
Red Hat Enterprise Linux 8.4 Update Services for SAP SolutionsRedHatshim-0:15.8-2.el8_4*
Red Hat Enterprise Linux 8.6 Extended Update SupportRedHatshim-0:15.8-2.el8_6*
Red Hat Enterprise Linux 8.8 Extended Update SupportRedHatshim-0:15.8-2.el8*
Red Hat Enterprise Linux 8.8 Extended Update SupportRedHatshim-unsigned-x64-0:15.8-2.el8*
Red Hat Enterprise Linux 9RedHatshim-0:15.8-4.el9_3*
Red Hat Enterprise Linux 9.0 Extended Update SupportRedHatshim-0:15.8-3.el9*
Red Hat Enterprise Linux 9.0 Extended Update SupportRedHatshim-unsigned-aarch64-0:15.8-2.el9*
Red Hat Enterprise Linux 9.0 Extended Update SupportRedHatshim-unsigned-x64-0:15.8-2.el9*
Red Hat Enterprise Linux 9.2 Extended Update SupportRedHatshim-0:15.8-3.el9_2*
Secureboot-dbUbuntubionic*
Secureboot-dbUbuntulunar*
Secureboot-dbUbuntutrusty*
Secureboot-dbUbuntuxenial*
ShimUbuntubionic*
ShimUbuntudevel*
ShimUbuntuesm-infra-legacy/trusty*
ShimUbuntuesm-infra/focal*
ShimUbuntuesm-infra/xenial*
ShimUbuntufocal*
ShimUbuntujammy*
ShimUbuntulunar*
ShimUbuntumantic*
ShimUbuntunoble*
ShimUbuntuoracular*
ShimUbuntuplucky*
ShimUbuntuquesting*
ShimUbuntutrusty*
ShimUbuntutrusty/esm*
ShimUbuntuxenial*
Shim-signedUbuntubionic*
Shim-signedUbuntudevel*
Shim-signedUbuntuesm-infra-legacy/trusty*
Shim-signedUbuntuesm-infra/focal*
Shim-signedUbuntuesm-infra/xenial*
Shim-signedUbuntufocal*
Shim-signedUbuntujammy*
Shim-signedUbuntulunar*
Shim-signedUbuntumantic*
Shim-signedUbuntunoble*
Shim-signedUbuntuoracular*
Shim-signedUbuntuplucky*
Shim-signedUbuntuquesting*
Shim-signedUbuntutrusty*
Shim-signedUbuntutrusty/esm*
Shim-signedUbuntuxenial*

Potential Mitigations

  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

References

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