How does Virus Blocker compare to "brand-name" virus blockers? Virus Blocker is based on the Bitdefender AV Engine, which is consistently in top 10 for detecting zero-hour threats. It also uses Scout IQ. Virus Blocker Lite is based on ClamAV, the well-respected open source virus scanner. Follow Have more questions? Submit a request Comments 0 comments Please sign in to leave a comment.