This malicious software is sent as an e-mail attachment disguised a PDF document and if open, will infect the victim's computer.
This Avast antivirus imitating Trojan will try to disable legitimate antivirus software and will steal your usernames and passwords (for your e-mail account, online banking etc).
This is how the Antivirus taskbar tray icon looks:
If you double click on the icon, the following dialog box will be displayed:
The text in the dialog box translates to: "Your Avast! Antivirus is being updated, wait."
If you receive any e-mail attachments, always check the file name extension; not because an e-mail attachment looks like a PDF or Word document, it doesn't mean it is. So, be careful when opening an e-mail attachment even if it appeared as if came from someone you know.
Any e-mail attachments with the following file name extensions should not be open: .exe, .scr, .com, .bat and .msi.