Ubuntu Security :: Log Files - 2 Users Logged In?

I read the log

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I found this print out:

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The line in bold is the security issue. There is only 1 user account on the system. There should only be 1 user logged in, not 2 users logged in. The remainder of the log file lists 1 user logged in, for similar log output. 2 users logged in does not appear again in the log file.

Does the second line of bold indicate that an attempt was made to log in to the system using SSH?

There was an internet connection interruption (no service) around the time of the log file event. The service did return, later.

Does that line indicate that an unauthorized user logged in to the system?