I have been thinking about self-hosting my personal photos on my linux server. After the recent backdoor was detected I'm more hesitant to do so especially because i'm no security expert and don't have the time and knowledge to audit my server. All I've done so far is disabling password logins and changing the ssh port. I'm wondering if there are more backdoors and if new ones are made I can't respond in time. Appreciate your thoughts on this for an ordinary user.
if you are self hosting and enjoy over-engineering systems... VLANS, ACLs between subnets and IDS/IPS should be part of.your thinking. separate things into zones of vulnerability / least-privilege and maintain that separation with an iron fist. this is a great rabbit hole to fall down if you have the time. however, given a skilled adversary with enough time and money, any network can be infiltrated eventually. the idea is to try to minimize the exposure when it happens.
if the above is not a part of your daily thinking, then don't worry about it too much. use a production OS like Debian stable, don't expose ports to the public internet and only allow systems that should initiate communication to the internet to actually do so (preferably only on their well known protocol ports - if possible).