Red Hat Security Advisory 2017-2563-01 - OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix: A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses.
6772db3539ac28058a8dcd85adcd01f09d836815a6d2fd1a69ba5c6d44438755