An issue was discovered in Arm Mbed TLS before 2.16.6 and 2.7.x before 2.7.15. An attacker that can get precise enough side-channel measurements can recover the long-term ECDSA private key by (1) reconstructing the projective coordinate of the result of scalar multiplication by exploiting side channels in the conversion to affine coordinates; (2) using an attack described by Naccache, Smart, and Stern in 2003 to recover a few bits of the ephemeral scalar from those projective coordinates via several measurements; and (3) using a lattice attack to get from there to the long-term ECDSA private key used for the signatures. Typically an attacker would have sufficient access when attacking an SGX enclave and controlling the untrusted OS.
2020-04-15T14:15:20.123
2024-11-21T04:56:23.837
Modified
CVSSv3.1: 4.7 (MEDIUM)
AV:L/AC:M/Au:N/C:P/I:N/A:N
3.4
2.9
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | arm | mbed_tls | < 2.7.15 | Yes |
| Application | arm | mbed_tls | < 2.16.6 | Yes |
| Operating System | fedoraproject | fedora | 31 | Yes |
| Operating System | fedoraproject | fedora | 32 | Yes |
| Operating System | debian | debian_linux | 10.0 | Yes |