> So you could either use readonly media (like Blurays) or PULL is mandatory.
Or like someone already commented you can use a server that allows push but doesn't allow to mess with older files. You can for example restrict ssh to only the scp command and the ssh server can moreover offer a chroot'ed environment to which scp shall copy the backups. And the server can for example daily rotate that chroot.
The push can then push one thing: daily backups. It cannot log in. It cannot overwrite older backups.
Short of a serious SSH exploit where the ransomware could both re-configure the server to accept all ssh (and not just scp) and escape the chroot box, the ransomware is simply not destroying data from before the ransomware found its way on the system.
My backup procedure does that for the one backup server that I have on a dedicated server: a chroot'ed ssh server that only accepts scp and nothing else. It's of course just one part of the backup procedure, not the only thing I rely on for backups.
P.S: it's not incompatible with also using read-only media
TacticalCoder's comments appear to be auto-deaded for the last week or so.
I did not see a likely reason in a quick review of their comment history.
You can view a comment directly by following the "... ago" link, and from there you can use the "vouch" link to revive the comment. I vouched for a few of TacticalCoder's recent comments.
Or like someone already commented you can use a server that allows push but doesn't allow to mess with older files. You can for example restrict ssh to only the scp command and the ssh server can moreover offer a chroot'ed environment to which scp shall copy the backups. And the server can for example daily rotate that chroot.
The push can then push one thing: daily backups. It cannot log in. It cannot overwrite older backups.
Short of a serious SSH exploit where the ransomware could both re-configure the server to accept all ssh (and not just scp) and escape the chroot box, the ransomware is simply not destroying data from before the ransomware found its way on the system.
My backup procedure does that for the one backup server that I have on a dedicated server: a chroot'ed ssh server that only accepts scp and nothing else. It's of course just one part of the backup procedure, not the only thing I rely on for backups.
P.S: it's not incompatible with also using read-only media