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teus

Member

Registered: 2020-09-26

Posts: 2

failed SSH logins in dmesg

How do I keep failed SSH logins from flooding dmesg and the system log? Besides switching to key logins, fail2ban or disabling SSH logging....
For example: [ 4164.178415] audit: type=1100 audit(1630246439.795:656): pid=1959 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:authentication grantors=? acct="admin" exe="/usr/bin/sshd" hostname=31.184.198.71 addr=31.184.198.71 terminal=ssh res=failed'
I can't really wrap my mind around the audit thing. The audit daemon isn't running on boot (inactive, dead). I had to create /var/log/audit/audit.log and now succesful logins go there, after a reboot, but the failed ones not.
Perhaps I could disable the kernel parameter, but sysctl -a doesn't list audit as a paremeter ( https://wiki.archlinux.org/title/Audit_framework )
Auditctl -l says there are no active rules.

Slithery

Administrator

From: Norfolk, UK

Registered: 2013-12-01

Posts: 5,776

Re: failed SSH logins in dmesg

https://bbs.archlinux.org/viewtopic.php?id=268868

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seth

Member

Registered: 2012-09-03

Posts: 51,543

Re: failed SSH logins in dmesg

You should™ block off the offenders rather than silencing the attacks, but https://wiki.archlinux.org/title/Audit_ … d_messages
(… -F exe="/usr/bin/sshd" … should™ work)

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ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,802

Re: failed SSH logins in dmesg

Well, the obvious first question:  Do you need to have your system accesible from the Internet?    The address indicates the attack you referenced did not come from your LAN. 
If you have an open port at a well known address on the Internet, it will be probed.  Continuously. 
If you don't want to block, and it is only for your use, you might consider port knocking.

https://wiki.archlinux.org/title/Port_knocking

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ugjka

Member

From: Latvia

Registered: 2014-04-01

Posts: 1,813

Website

Re: failed SSH logins in dmesg

2FA is also something you can consider if you really need password auth

Last edited by ugjka (2021-08-29 17:13:31)

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