Bug 605414 (CVE-2016-7056)

Summary:	[TRACKER] ECDSA P-256 timing attack key recovery (CVE-2016-7056)
Product:	Gentoo Security	Reporter:	Thomas Deutschmann (RETIRED) <whissi>
Component:	Vulnerabilities	Assignee:	Gentoo Security <security>
Status:	RESOLVED FIXED
Severity:	normal	Keywords:	Tracker
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---
Bug Depends on:	605416, 605418
Bug Blocks:

Description Thomas Deutschmann (RETIRED) gentoo-dev

2017-01-11 21:51:23 UTC

The signing function in crypto/ecdsa/ecdsa_ossl.c in certain OpenSSL versions and forks is vulnerable to timing attacks when signing with the standardized elliptic curve P-256 despite featuring constant-time curve operations and modular inversion. A software defect omits setting the BN_FLG_CONSTTIME flag for nonces, failing to take a secure code path in the BN_mod_inverse method and therefore resulting in a cache-timing attack vulnerability. A malicious user with local access can recover ECDSA P-256 private keys.


References:

http://seclists.org/oss-sec/2017/q1/52
http://eprint.iacr.org/2016/1195

Comment 1 Aaron Bauman (RETIRED) gentoo-dev

2018-01-21 02:36:53 UTC

All dependent bugs closed.