A vulnerability scan is an automated tool that conducts a nonintrusive scan of a merchant or service provider’s system to remotely review networks and Web applications based on the external-facing Internet protocol (IP) addresses provided by the merchant or service provider. The scan pinpoints vulnerabilities in operating systems, services and devices that could be used by hackers to target the company’s private network.  Approved Scanning Vendors (ASVs) do not require the merchant or service provider to install any software on their systems, and no denial-of-service attacks will be performed.