Apparatus, system, method and computer program product for verifying the integrity of remote network devices that request access to network services and resources. Unintended computer programs such as viruses, worms, or Trojan horses, may compromise remote devices. The invention involves downloading verification software over the web into the web browser of a client for the purpose of performing checks to verify the integrity and security of the client's device or system. The results of such checks are returned over the web to be used in security decisions involving authentication and the grant of authorization to access services and resources.