Summary:
Automatic disk unlocking with TPM2 and systemd-cryptenroll/clevis can leave your system vulnerable to decryption by attackers with brief physical access. Most setups fail to verify LUKS identity, susceptible to filesystem confusion attacks. By exploiting real systems, attackers can mimic the original root filesystem, decrypt the partition, and introduce malicious software. One recommended solution involves deriving a value from the volume key and extending Platform Configuration Registers (PCR) 15 to confirm volume authenticity. Guides for TPM2 disk unlocking are abundant, but many overlook security concerns. Notably, adding PCRs 0-7 opens vulnerabilities to rogue operating systems. Careful PCR selection and manual verification are essential to protect against these vulnerabilities.
https://oddlama.org/blog/bypassing-disk-encryption-with-tpm2-unlock/