4

So, I need to know when my account in ubuntu is accessed. Is there any command that will show me the Exact Time when that happened. I need this because I suspect someone is remotely controlling my computer, and changing things.

7

last command to the rescue

The last command shows by a given user name or all user names:

$ last rick
rick     tty7         :0               Wed Apr 24 16:25    gone - no logout
rick     tty8         :1               Wed Apr 24 16:24 - down   (00:00)
rick     tty7         :0               Tue Apr 23 20:12 - down   (20:06)
rick     tty7         :0               Tue Apr 23 18:30 - crash  (01:42)
  (...SNIP...)
rick     tty7         :0               Tue Apr  2 16:52 - down   (00:31)
rick     tty7         :0               Tue Apr  2 03:14 - crash  (13:37)

By default it only shows history for the current month. If you need to go further back in history than one month, you can read the /var/log/wtmp.1 file with the last command.

last -f wtmp.1 rick will show the previous month's history of logins for user rick:

$ last -f /var/log/wtmp.1 rick
rick     tty7         :0               Sun Mar 31 16:53    gone - no logout
rick     tty7         :0               Sat Mar 30 19:18 - down   (13:20)
  (...SNIP...)
rick     tty7         :0               Fri Mar  1 20:55 - down   (11:55)

wtmp.1 begins Fri Mar  1 18:23:28 2019

Security is hardened such that normal users can't write or delete the file:

$ ll /var/log/wtmp.1
-rw-rw-r-- 1 root utmp 107520 Mar 31 16:53 /var/log/wtmp.1

Console only logins

The console uses the login command which records data to /var/log/lastlog:

$ ll /var/log/lastlog
-rw-rw-r-- 1 root utmp 292292 Apr 24 16:22 /var/log/lastlog

The lastlog file though cannot be tampered with so easily when you look at the File Owner and File Group above. "Normal" users just have read access. It's a binary file though so you can't just cat it and get meaningful information. Use this command instead:

$ lastlog
Username         Port     From             Latest
root                                       **Never logged in**
daemon                                     **Never logged in**
bin                                        **Never logged in**
sys                                        **Never logged in**
  (...SNIP...)
usbmux                                     **Never logged in**
rick             tty1                      Wed Nov 28 04:19:53 -0700 2018
vnstat                                     **Never logged in**

It's interesting to see all the different user IDs that could log in but never have and never should. I was surprised I haven't logged into the console / terminal since November last year.

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4

This would be shown in /var/log/auth.log if the 'person' controlling your system remotely is not smart enough to clean up the logs. You might be able to see login data by using:

sudo cat /var/log/auth.log | grep USERNAME

(where USERNAME is your user).

Beyond this, however, if there's nothing in this log, and you really do think you're being remote-controlled, I'd suggest clean-installing your system and starting from scratch with different passwords and better hardening your system.

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