Sana Security, a San Mateo, Ca. seller of software that helps consumers detect and removes things like comptuer viruses and worms, said it has raised $12 million more in venture capital.

Don Listwin, a former Cisco exec, has also taken over as chief executive.

This is the company’s fifth round of investment, and was led by El Dorado Ventures and Listwin himself.

The company has already raised at least $29 million from investors since 2000, including Bay Partners, Sevin Rosen Funds and The Entrepreneurs Fund.