CVE-2021-3565: 
NixOS vulnerability analysis and mitigation

CVE-2021-3565 is a security vulnerability discovered in tpm2-tools versions before 5.1.1 and before 4.3.2. The vulnerability was identified in the tpm2_import command, which used a fixed AES key for the inner wrapper. The issue was disclosed on June 4, 2021, affecting various versions of the tpm2-tools package, which provides utilities for management and utilization of Trusted Platform Module (TPM) 2.0 devices (NVD, CVE).

The vulnerability stems from the tpm2import command's implementation, where it utilized a fixed AES wrapping key for the inner wrapper. This implementation weakness becomes particularly significant when no encrypted session with the TPM is used ([Red Hat Bugzilla](https://bugzilla.redhat.com/showbug.cgi?id=1964427)).

The primary impact of this vulnerability is on data confidentiality. When no encrypted session with the TPM is used, an attacker performing a Man-in-the-Middle (MITM) attack could potentially unwrap the inner portion and reveal the key being imported (CVE).

The vulnerability has been addressed in tpm2-tools versions 5.1.1 and 4.3.2. Users are advised to upgrade to these or later versions. Red Hat has released security updates through RHSA-2021:4413 for affected versions (Red Hat Advisory).