CVE-2018-5407

A microprocessor side-channel vulnerability was found 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.

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.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

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.