Insufficient Entropy in libtpms - CVE-2021-3505

Vulnerability identifier: #VU54502

CSH Severity: Low

CVSS v4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-3505

CWE-ID: CWE-331

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to decrypt data.

The vulnerability exists in the TPM 2 implementation, which returns 2048 bit keys with ~1984 bit strength due to a bug in the TCG specification. The bug is in the key creation algorithm in RsaAdjustPrimeCandidate(), which is called before the prime number check.

libtpms
openEuler
Fedora
PowerVM Hypervisor
libtpms
libtpms-debugsource
libtpms-devel
libtpms-debuginfo

Install updates from vendor's website.

libtpms - update to 0.8.0
PowerVM Hypervisor - update to FW1050.00
libtpms - update to 0.7.3-7
libtpms-debugsource - update to 0.7.3-7
libtpms-devel - update to 0.7.3-7
libtpms-debuginfo - update to 0.7.3-7
libtpms - update to 0.8.2-0.20210426git729fc6a4ca.fc33

• https://bugzilla.redhat.com/show_bug.cgi?id=1950046
• https://github.com/stefanberger/libtpms/issues/183
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUCZX4S53TUNTSGTCRDNOQZV2V2RI4RJ/

• Insufficient Entropy in libtpms
• Insufficient entropy in IBM PowerVM Hypervisor
• openEuler 20.03 LTS SP1 update for libtpms
• Fedora 33 update for libtpms