Blank named user ftp logfile

[Johnny5_Hull]

This is a strange one, I have never noticed this before, and not sure if it is a bug or if someone has been accessing my server somehow.

 

Within the TCA logfiles, under useractivity, there are the log files for each users ftp activity. However I have just noticed one called FTP..txt which is odd, as they are usually FTP.username.txt.

 

It appears that either TCA hasnt registered the log file correctly, or someone was able to use the ftp function, but without actually being a registered user!

 

Has anyone else come across this, or have any ideas on why it has just appeared?