CVE-2020-10932
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-10932
Vendor advisory: arch — https://security.archlinux.org/ASA-202007-5
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| arch | fixed | 2.16.7-1 | |
| debian | bookworm | fixed | 2.16.9-0.1 |
| debian | bullseye | fixed | 2.16.9-0.1 |
| debian | forky | fixed | 2.16.9-0.1 |
| debian | sid | fixed | 2.16.9-0.1 |
| debian | trixie | fixed | 2.16.9-0.1 |
References
Verify integrity in audit chain (admin only). AS-IS.