FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

Mbed TLS -- Cache attack against RSA key import in SGX

Affected packages
mbedtls < 2.16.5


VuXML ID 056ea107-5729-11ea-a2f3-001cc0382b2f
Discovery 2020-02-18
Entry 2020-02-24

Janos Follath reports:

If Mbed TLS is running in an SGX enclave and the adversary has control of the main operating system, they can launch a side channel attack to recover the RSA private key when it is being imported.

The attack only requires access to fine grained measurements to cache usage. Therefore the attack might be applicable to a scenario where Mbed TLS is running in TrustZone secure world and the attacker controls the normal world or possibly when Mbed TLS is part of a hypervisor and the adversary has full control of a guest OS.