avast! detects all types of malware.
Definition of malware : Malware includes computer viruses, ransomware, worms, trojan horses, rootkits, keyloggers, dialers, spyware, adware, malicious BHOs, rogue security software, and other malicious programs; the majority of active malware threats are usually worms or trojans rather than viruses.
Source :
http://en.wikipedia.org/wiki/Malware