CVE-2020-8918

TPM 1.2 key authorization values are vulnerable to a TPM transport eavesdropper

State: Published
Severity: 6.3 Medium
Published: Aug 11, 2020
Updated: Aug 4, 2024
Reserved: Feb 12, 2020

Description

An improperly initialized 'migrationAuth' value in Google's go-tpm TPM1.2 library versions prior to 0.3.0 can lead an eavesdropping attacker to discover the auth value for a key created with CreateWrapKey. An attacker listening in on the channel can collect both 'encUsageAuth' and 'encMigrationAuth', and then can calculate 'usageAuth ^ encMigrationAuth' as the 'migrationAuth' can be guessed for all keys created with CreateWrapKey. TPM2.0 is not impacted by this. We recommend updating your library to 0.3.0 or later, or, if you cannot update, to call CreateWrapKey with a random 20-byte value for 'migrationAuth'.

Scores

CVSS	Score	Vector	Source
3.1	6.3 Medium	CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N	Google

Weaknesses

CWE-665 Improper Initialization

Affected Products

Product	Versions
google/go-tpm libraryGoogle LLC	stable to before 0.3.0Affected

References

https://github.com/google/go-tpm/security/advisories/GHSA-5x29-3hr9-6wpw

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