I have Windows 8.
You understood everything right, but i thought, that Aida should report the newest antivirus base, not the oldest one. I was wrong.
Btw, I've found solution!
Symantec 12 (SEP) by default disables (without uninstalling) Windows Defender, so Defender database stops updating.
So, to remove reporting about Defender old virus databases from AIDA, "/Program Files/Windows Defender" folder should be renamed to something else, for example "/Program Files/Windows Defender OLD"