A flaw was found in microprocessor execution engine sharing on SMT (e.g. Hyper-Threading) architectures. An attacker running a malicious process on the same core of the processor as the victim process, can extract certain secret information.

The reporter is able to steal an OpenSSL (<= 1.1.0h) P-384 private key from a TLS server using this new side-channel vector. It is a local attack in the sense that the malicious process must be running on the same physical core as the victim (an openSSL-powered TLS server in this case). But in general any application which branches on a secret value may be affected.

References: https://seclists.org/oss-sec/2018/q4/123

A flaw was found in OpenSSL versions from 1.1.0 through 1.1.0i inclusive and version 1.1.1. The OpenSSL ECDSA signature algorithm has been shown to be vulnerable to a timing side channel attack. An attacker could use variations in the signing algorithm to recover the private key.

References: https://www.openssl.org/news/secadv/20181029.txt

Upstream Patch: https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=56fb454d281a023b3f950d969693553d3f3ceea1 https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=b1d6d55ece1c26fa2829e2b819b038d7b6d692b4