ClamAV is an Opensource Antivirus option for Linux/Unix O/S and protects your system against Trojans, malware and other security threats.
Linux is known for its security and believed as one of the most secure O/S. You might have heard people talking about how secure it is, and guaranteed for no Virus Attack on Linux Operating Systems. But in reality, Linux Operating Systems are also being infected by viruses.
If you want to protect your Linux O/S, Network or VPC and looking for an Open-Source Antivirus Software, you can go for ClamAV.