this post was submitted on 30 Sep 2024
134 points (99.3% liked)

Self Hosted - Self-hosting your services.

11287 readers
145 users here now

A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don't control.

Rules

Important

Beginning of January 1st 2024 this rule WILL be enforced. Posts that are not tagged will be warned and if not fixed within 24h then removed!

Cross-posting

If you see a rule-breaker please DM the mods!

founded 3 years ago
MODERATORS
 

I accidentally attempted to SSH into one of my servers from a device that did not contain my ssh key. I configure all of my servers to only allow authentication via cryptographic keys. Root ssh as well as password auth are disabled.

To my surprise, I was able to log in to my server with a password despite this. Baffled, I first tried some other servers. 2 of the 5 other servers I tried were accessabke via password.

After some swift investigation the culprit was found, a cloud-init ssh config in sshd_config.d/ with one line: password_authentication Yes.

So TLDR PSA....if you run a server in any type of virtualized environment, including a VPS, check your /etc/ssh/sshd_config.d/ folder. And more broadly, actually thoroughly test your ssh access to confirm everything is working as you intend it to.

top 6 comments
sorted by: hot top controversial new old
[–] friend_of_satan 43 points 2 days ago

Show your effective sshd server config: sudo sshd -T

[–] [email protected] 18 points 2 days ago* (last edited 2 days ago)

This is good advice in general. Think of it like penetration testing. You really should verify what you can actually access remotely on a device and not assume you have any level of protection until you’ve tried it.

Log files can also contain signs of attack like password guessing. You should review these on a regular basis.

[–] Boris_NotTooBadinoff 4 points 2 days ago* (last edited 1 day ago)

Had a similar issue with tlp recently. I just happened to notice the laptop battery was at 100%, and said it was charging. I double and triple checked the config file, but the tlp-stat -b still showed the thresholds at 90%-100%.

Turns out tlp, at some point, started ignoring /etc/tlp.conf, and was pointing to /etc/default/tlp

[–] [email protected] 10 points 2 days ago

Good advice. One should always test, for correctness, not just infer.

[–] [email protected] 8 points 2 days ago

I could even go further into saying: always test every change you make, do not assume the change has been made because you updated a file.

[–] [email protected] -4 points 2 days ago

OpenSSH right? What version?
No issues with Dropbear