Trusted Firmware-m: Incorrect Comparison
CVE-2023-40271 is a high-severity incorrect comparison vulnerability in Trusted Firmware-m from TrustedFirmware, 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 Trusted Firmware-m versions: 1.6.0; 1.6.1; 1.7.0, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.39% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Trusted Firmware-m you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on git.trustedfirmware.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Trustedfirmware | Trusted Firmware-m | 1.6.0; 1.6.1; 1.7.0; 1.8.0 | Not stated |
Version data comes from NVD's product matching. 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
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by NVD.
Official description
In Trusted Firmware-M through TF-Mv1.8.0, for platforms that integrate the CryptoCell accelerator, when the CryptoCell PSA Driver software Interface is selected, and the Authenticated Encryption with Associated Data Chacha20-Poly1305 algorithm is used, with the single-part verification function (defined during the build-time configuration phase) implemented with a dedicated function (i.e., not relying on usage of multipart functions), the buffer comparison during the verification of the authentication tag does not happen on the full 16 bytes but just on the first 4 bytes, thus leading to the possibility that unauthenticated payloads might be identified as authentic. This affects TF-Mv1.6.0, TF-Mv1.6.1, TF-Mv1.7.0, and TF-Mv1.8.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Comparison
The product compares two entities in a security-relevant context, but the comparison is incorrect.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/security/security_advisories/cc3xx_partial_tag_…Exploit, Mitigation, Technical Description
Patches and release notes
Other vulnerabilities in Trusted Firmware-m
- 7.0 High severity
- 9.8 Critical severity
- 5.5 Medium severity
Arm Trusted Firmware Out-of-Bounds Write Exploited
Recent Incorrect Comparison vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
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