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

2020-08-1118:35:11

CWE-665

Google

www.cve.org

6.3 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

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

6.8 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

20.4%

JSON

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’.

CNA Affected

[
  {
    "product": "google/go-tpm library",
    "vendor": "Google LLC",
    "versions": [
      {
        "lessThan": "0.3.0",
        "status": "affected",
        "version": "stable",
        "versionType": "custom"
      }
    ]
  }
]