I rebooted my Linux box into Windows Vista several times in the last two days while moving things over to VMWare Fusion. All day today, my disk drive has given a little spin every two or three seconds.
When I first noticed it, I tried searching around with iostat and top to see if I had some process run amok. Finding nothing, I tried rebooting.
The magical reboot was not so magical. My machine was still merrily hitting the disk every couple seconds.
I searched around the web for “disk activity” linux and “disk activity” ubuntu. I found recommendations that I:
- Kill processes that poll for new media
- Eliminate access time tracking on my filesystem, and
- Set syslog not to flush some of its logs
All of those seemed bogus to me. None of them seemed like anything that would have changed yesterday or today. But, the last one got me thinking. What logs do I have that do get flushed on every message? Are any of them going batty today?
Sure enough, /var/log/auth.log was getting hit every two or three seconds. Someone was trying to guess logins on my machine.
; logname= uid=0 euid=0 tty=ssh ruser= rhost=nitro.xyzdns.net user=backup
May 28 04:57:59 evariste sshd: Failed password for backup from 209.51.159.
194 port 54874 ssh2
May 28 04:57:59 evariste sshd: Invalid user guest from 18.104.22.168
May 28 04:57:59 evariste sshd: pam_unix(sshd:auth): check pass; user unkno
May 28 04:57:59 evariste sshd: pam_unix(sshd:auth): authentication failure
; logname= uid=0 euid=0 tty=ssh ruser= rhost=nitro.xyzdns.net
May 28 04:58:01 evariste sshd: Failed password for invalid user guest from
22.214.171.124 port 54992 ssh2
Looking back through the last week, I’ve had a few spats of bogus login attempts. Most of them were just four or five attempts in a row. This one today had gone for twelve hours.
I threw that IP address into /etc/hosts.deny. Now, all is quiet. Well, except my need to make sure I don’t let things go for twelve hours again….