CVE-2020-10932

Name	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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-3249-1
Debian Bugs	963159

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
mbedtls (PTS)	stretch (security), stretch (lts), stretch	2.4.2-1+deb9u4	vulnerable
	buster (security), buster, buster (lts)	2.16.9-0~deb10u1	fixed
	bullseye	2.16.9-0.1	fixed
	bookworm	2.28.3-1	fixed
	trixie	2.28.8-1	fixed
	sid	3.6.2-3	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
mbedtls	source	buster	2.16.9-0~deb10u1		DLA-3249-1
mbedtls	source	(unstable)	2.16.9-0.1			963159

Notes

[stretch] - mbedtls <no-dsa> (Minor issue)
https://tls.mbed.org/tech-updates/releases/mbedtls-2.16.6-and-2.7.15-released
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-04