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CVE-2023-22745

MEDIUMCVSS 6.4/10EPSS 0.52%

Last modified

CVE-2023-22745 is a medium-severity vulnerability rated 6.4/10 on the CVSS scale. tpm2-tss is an open source software implementation of the Trusted Computing Group (TCG) Trusted Platform Module (TPM) 2 Software Stack (TSS2). In versions prior to 4.1.0-rc0, 4.0.1, and 3.2.2-rc1, `Tss2_RC_SetHandler` and `Tss2_RC_Decode` both index into `layer_handler` with an 8 bit layer number, but the array only has `TPM2_ERROR_TSS2_RC_LAYER_COUNT` entries, so trying to add a handler for higher-numbered layers or decode a response code with such a layer number reads/writes past the end of the buffer. EPSS estimates a 0.52% chance of exploitation in the next 30 days.

Description

tpm2-tss is an open source software implementation of the Trusted Computing Group (TCG) Trusted Platform Module (TPM) 2 Software Stack (TSS2). In versions prior to 4.1.0-rc0, 4.0.1, and 3.2.2-rc1, `Tss2_RC_SetHandler` and `Tss2_RC_Decode` both index into `layer_handler` with an 8 bit layer number, but the array only has `TPM2_ERROR_TSS2_RC_LAYER_COUNT` entries, so trying to add a handler for higher-numbered layers or decode a response code with such a layer number reads/writes past the end of the buffer. This Buffer overrun, could result in arbitrary code execution. An example attack would be a MiTM bus attack that returns 0xFFFFFFFF for the RC. Given the common use case of TPM modules an attacker must have local access to the target machine with local system privileges which allows access to the TPM system. Usually TPM access requires administrative privilege. Versions 4.1.0-rc0, 4.0.1, and 3.2.2-rc1 fix the issue.

Metrics

CVSS 3.1
6.4/10

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.52%

40.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
Tpm2 Software Stack ProjectTpm2 Software Stack< 3.2.2
Tpm2 Software Stack ProjectTpm2 Software Stack>= 4.0.0, < 4.1.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2023-22745?
tpm2-tss is an open source software implementation of the Trusted Computing Group (TCG) Trusted Platform Module (TPM) 2 Software Stack (TSS2). In versions prior to 4.1.0-rc0, 4.0.1, and 3.2.2-rc1, `Tss2_RC_SetHandler` and `Tss2_RC_Decode` both index into `layer_handler` with an 8 bit layer number, but the array only has `TPM2_ERROR_TSS2_RC_LAYER_COUNT` entries, so trying to add a handler for higher-numbered layers or decode a response code with such a layer number reads/writes past the end of the buffer. This Buffer overrun, could result in arbitrary code execution. An example attack would be a MiTM bus attack that returns 0xFFFFFFFF for the RC. Given the common use case of TPM modules an attacker must have local access to the target machine with local system privileges which allows access to the TPM system. Usually TPM access requires administrative privilege. Versions 4.1.0-rc0, 4.0.1, and 3.2.2-rc1 fix the issue.
How severe is CVE-2023-22745?
CVE-2023-22745 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.52% probability of exploitation in the next 30 days.
How do I fix CVE-2023-22745?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST