Antivirus kernel based on certified antivirus engine.
Resident protection comprising individual modules or "shields", each of which can be individually configured or disabled:
Standard Shield — Real-time protection against viruses and other malware threats.
IM shield — Instant Messaging protection. (Scanning of files transferred through instant messaging applications)
P2P shield — P2P protection.
Internet Mail — E-mail scanning.
Outlook/Exchange — Microsoft Outlook/Exchange scanning.
Web Shield — HTTP protection (local transparent proxy). Version 4.8 also allows the blocking of URLs.
Script blocker — Professional version only; scans webpages for malicious scripts.
Network Shield — Basic protection against well-known network worms. Acts as an Intrusion Detection System.
Anti-spyware capabilities
Anti-rootkit capabilities
Virus Recovery Database (VRDB) — Allows repair of malware infected files.
Self-Protection — Prevents malware from terminating avast! processes and damaging avast! files.
Automatic incremental updates — Updates of both the program and the virus database which is used to identify potential threats — Avast! updates its virus definitions on a regular basis (sometimes multiple updates daily) and this process is automated by default.
Audible alarms — Vocal warnings and notices such as "Caution, a virus has been detected!" and "Virus database has been updated."
Boot-time scan — Users can schedule a boot-time scan to remove infections that load during Windows startup.
Virus Chest — Quarantine; folder where infected files can be stored. The virus chest also stores vital system files to protect them from damage by malware. Users can also add their own files to the virus chest. Once in the chest, a file cannot be executed; double-clicking the file will instead display information about the file.
Skinnable user interface