Avast tries to get unauthorized access to my FTP server

Avast Free Antivirus / Premium Security
1

I have the Windows 2003 based home server. Every time I start avast intellegent scan my event log reports about trying to access to my FTP server with the different logins-passwords. About 50 attempts for each time. Here is an example of the message in the log:

Event Type: Warning
Event Source: MSFTPSVC
Event Category: None
Event ID: 100
Date: 27.07.2017
Time: 20:09:54
User: N/A
Computer: ASPIREKOSSERV
Description:
The server was unable to logon the Windows NT account ‘user’ due to the following error: Logon failure: unknown user name or bad password. The data is the error code.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 2e 05 00 00 …

Such attemptes are take place while manual scanning or while sheduled scanning.
Last names the avast tried are:
user
sysadm
support
smc
root
manager
login
customer
cusadmin
comcast
etc.

What a nasty bug?

2
What a nasty bug?
[b]Avast Antivirus: Running Smart Scan [/b] >> https://www.avast.com/faq.php?article=AVKB159
Smart Scan is an all-in-one scan that detects malware, out-of-date software, browser add-ons with poor reputations, network threats, performance issues, [b]and passwords that are weak, duplicated, or compromised.[/b]
I guess what you see is related to avast password check ....
3

I beleave that such behaviour of the AV compromises it. What should I think about when I see that?