OpenSSH Now Stores Only Encrypted Keys in the Memory of the Operating System. The latest update protects the system against almost all types of side-channel attacks. It should be noted that this patch just mitigates the threat and is not a permanent solution. It will remove this protection in a few years when computer architecture becomes less unsafe, developer Damien Miller says. Miller: “Attackers must recover the entire prekey with high accuracy before they can attempt to decrypt the shielded private key, but the current generation of attacks have bit error rates”
Source: https://thehackernews.com/2019/06/openssh-side-channel-vulnerability.html