Webroot, the 450-strong California enterprise, plans to integrate Prevx's technology into its cloud security services, and will retain its 20-member staff.
"Webroot and Prevx share a common vision for revolutionising what we believe is a market in need of dramatic change," said Dick Williams, chief executive officer at Webroot.
Mel Morris, Prevx founder, said cybercrime has become too sophisticated for traditional malware detection. "Webroot shares our desire to innovate at a time when our industry has fallen behind in the war against online crime," he said.
The deal follows Webroot's acquisition of BrightCloud in July and Email Systems Scandinavia in March.
This story was first published by Computer Weekly