Описание
EVE Seals Vault Key With SHA1 PCRs
Impact
The vault key is sealed using SHA1 PCRs instead of SHA256 PCRs
Thus an attacker with physical access to an EVE-OS device can try to brute force creating a kernel or rootfs image which produces the same SHA1 PCR but with malicious content.
Patches
Fixed in 9.4.3-lts and 10.1.0
Workarounds
None
Пакеты
github.com/lf-edge/eve
< 0.0.0-20230519072751-977f42b07fa9
0.0.0-20230519072751-977f42b07fa9
Связанные уязвимости
Vault Key Sealed With SHA1 PCRs The measured boot solution implemented in EVE OS leans on a PCR locking mechanism. Different parts of the system update different PCR values in the TPM, resulting in a unique value for each PCR entry. These PCRs are then used in order to seal/unseal a key from the TPM which is used to encrypt/decrypt the “vault” directory. This “vault” directory is the most sensitive point in the system and as such, its content should be protected. This mechanism is noted in Zededa’s documentation as the “measured boot” mechanism, designed to protect said “vault”. The code that’s responsible for generating and fetching the key from the TPM assumes that SHA256 PCRs are used in order to seal/unseal the key, and as such their presence is being checked. The issue here is that the key is not sealed using SHA256 PCRs, but using SHA1 PCRs. This leads to several issues: • Machines that have their SHA256 PCRs enabled but SHA1 PCRs disabled, as