Table of Contents
This is a timing side-channel flaw on processors which implement SMT/Hyper-Threading architectures. It can result in leakage of secret data in applications such as OpenSSL that has secret dependent control flow at any granularity level. In order to exploit this flaw, the attacker needs to run a malicious process on the same core of the processor as the victim process.
CVSS v3 metrics
|CVSS3 Base Score||4.8|
|CVSS3 Base Metrics||CVSS:3.0/AV:P/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N|
Red Hat Security Errata
|Red Hat Enterprise Linux 7 (openssl)||RHSA-2019:0483||2019-03-13|
AcknowledgementsRed Hat would like to thank Billy Bob Brumley, Cesar Pereida Garcia, Sohaib ul Hassan, Nicola Tuveri (Tampere University of Technology; Finland), and Alejandro Cabrera Aldaya (Universidad Tecnologica de la Habana CUJAE; Cuba) for reporting this issue.
At this time Red Hat Engineering is working on patches for openssl package in Red Hat Enterprise Linux 7 to address this issue. Until fixes are available, users are advised to review the guidance supplied in the L1 Terminal Fault vulnerability article: https://access.redhat.com/security/vulnerabilities/L1TF and decide what their exposure across shared CPU threads are and act accordingly.