Tracking Down Ubuntu BASH Session Closing
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I have an Ubuntu server (not mine, and it has a GUI installed) that was running 16.04 that we just updated to 18.04. For the most part, everything is running fine. One weird issue is that SSH sessions are closed quickly. I have no idea where it is coming from. I've not found anything oddly configured, yet. Basically you get logged out every fifteen seconds or so, but it does not log you out if some command is running, thankfully. So running an update, or top, you are fine. But seconds after they stop, you are out.
KeepAlives are on. I can't find any odd time outs. When you sudo to root (aka sudo -i su) it literally types in "exit" and you drop to your user after X seconds. Then as the user, it types "logout" in your session and the session drops.
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Hopefully one of these links can help.
https://www.linuxquestions.org/questions/linux-newbie-8/ssh-session-automatically-closing-698502/
https://unix.stackexchange.com/questions/166975/ssh-connection-to-server-closed-after-authentication-immediately
https://unix.stackexchange.com/questions/193044/ssh-connection-to-server-closed-immediately-after-authentication -
@scottalanmiller said in Tracking Down Ubuntu SSH Session Closing:
When you sudo to root (aka sudo -i su) it literally types in "exit" and you drop to your user after X seconds. Then as the user, it types "logout" in your session and the session drops.
have never even heard of something like this.. how the hell would anything type characters into your sessions.
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For CIS compliance they recommend you set under
/etc/profile.d/to set auto logout. Is there anything set there?
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@JaredBusch said in Tracking Down Ubuntu SSH Session Closing:
@scottalanmiller said in Tracking Down Ubuntu SSH Session Closing:
When you sudo to root (aka sudo -i su) it literally types in "exit" and you drop to your user after X seconds. Then as the user, it types "logout" in your session and the session drops.
have never even heard of something like this.. how the hell would anything type characters into your sessions.
IKR? It's really odd.
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@IRJ what's odd here is that it will time out as you are typing. So it isn't a timeout in the normal sense. You can run a command, and run another say within one second. Literally that fast. And it might kick you in between.
And when it does, it puts "logout" into the session.
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Just tested one and I logged in and within two seconds it had logged me out again.
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@scottalanmiller said in Tracking Down Ubuntu SSH Session Closing:
Just tested one and I logged in and within two seconds it had logged me out again.
Could it be some strange cron job or something? Or did this start after a system upgrade?
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Can you scp files?
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I would try to download some config files so I could look at them
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@IRJ said in Tracking Down Ubuntu SSH Session Closing:
Can you scp files?
I'm sure that I can. I'll get some.
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@dafyre said in Tracking Down Ubuntu SSH Session Closing:
@scottalanmiller said in Tracking Down Ubuntu SSH Session Closing:
Just tested one and I logged in and within two seconds it had logged me out again.
Could it be some strange cron job or something? Or did this start after a system upgrade?
Could be, definitely. But I looked and haven't found one.
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Created a new user from scratch. Same issue just seconds after first login.
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I'm pretty sure that it is not SSH related, because sudo sessions get closed, too.
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I've switched my shell to zsh and so far, no logouts.
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If I use zsh, I'm good. If I enter BASH from zsh, I get kicked out after several seconds. Definitely is something to do with BASH.
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@IRJ TMOUT variable never appears in /etc
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I manually set the TMOUT variable to 0 to disable it, and it still happens. So that is not what is being used.
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Tried disabling AppArmor, but that did nothing.
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