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.

Weakness classification

• nvd@nist.gov: CWE-203

Primary references

• cve@mitre.org — Mailing List, Third Party Advisory
• cve@mitre.org — Mailing List, Third Party Advisory
• cve@mitre.org — Mailing List, Third Party Advisory
• cve@mitre.org — Release Notes
• cve@mitre.org — Vendor Advisory
• cve@mitre.org — Vendor Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Mailing List, Third Party Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Mailing List, Third Party Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Mailing List, Third Party Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Release Notes
• af854a3a-2127-422b-91ae-364da2661108 — Vendor Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Vendor Advisory