CyberSecBulletin
CVE-2024-32883NVD status: Deferred

mcuboot: Improper Validation of Integrity Check Value

Published Updated By the CyberSecBulletin desk

CVE-2024-32883 is a high-severity improper validation of integrity check value vulnerability in mcuboot from Mcu-tools, with a CVSS 3.1 base score of 7.7 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected mcuboot versions: <= 1.11.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of mcuboot you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Mcu-toolsmcuboot<= 1.11.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
LowSome restricted data can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:H. Scored by CNA (github.com).

Official description

MCUboot is a secure bootloader for 32-bits microcontrollers. MCUboot uses a TLV (tag-length-value) structure to represent the meta data associated with an image. The TLVs themselves are divided into two sections, a protected and an unprotected section. The protected TLV entries are included as part of the image signature to avoid tampering. However, the code does not distinguish which TLV entries should be protected or not, so it is possible for an attacker to add unprotected TLV entries that should be protected. Currently, the primary protected TLV entries should be the dependency indication, and the boot record. An injected dependency value would primarily result in an otherwise acceptable image being rejected. A boot record injection could allow fields in a later attestation record to include data not intended, which could cause an image to appear to have properties that it should not have. As a workaround, disable the boot record functionality.

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

The underlying weakness: Improper Validation of Integrity Check Value

The product does not validate or incorrectly validates the integrity check values or checksums of a message.

How developers prevent this class of flaw

  • The protocol specification describes the algorithm used for calculating the checksum. It is then a matter of implementing the calculation and verifying that the calculated checksum and the received checksum match.

More Improper Validation of Integrity Check Value vulnerabilities (CWE-354)

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

Recent Improper Validation of Integrity Check Value vulnerabilities

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