Vulnerability · Published Aug 11, 2020 · Assigned by Google

CVE-2020-8918TPM 1.2 key authorization values are vulnerable to a TPM transport eavesdropper

Medium 6.3

In plain English

A medium-severity security flaw in google/go-tpm library from Google LLC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.3Medium

Exploit odds (30 days)0.2%top 92.4% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official 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'.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/google/go-tpm	0.3.0	GHSA-5x29-3hr9-6wpw
Go	github.com/google/go-tpm	0.3.0	GO-2021-0095

Affected products (as reported)

Vendor	Product	Versions
Google LLC	google/go-tpm library	stable – before 0.3.0

Weakness: CWE-665 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

References

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