Vulnerability CVE-2020-8918


Published: 2020-08-11

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'.

Type:

CWE-665

(Improper Initialization)

CVSS2 => (AV:L/AC:L/Au:N/C:P/I:P/A:N)

CVSS Base Score
Impact Subscore
Exploitability Subscore
3.6/10
4.9/10
3.9/10
Exploit range
Attack complexity
Authentication
Local
Low
No required
Confidentiality impact
Integrity impact
Availability impact
Partial
Partial
None
Affected software
Google -> Go-tpm 

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

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