Embodiments of the invention provide methods and systems for using policy enforcement for securing open devices and networks. The method includes accessing, by a policy enforcer, a plurality of policies configured to enforce network integrity and monitoring programs and/or services running on a device. The method further includes based on at least one of the plurality of policies, comparing the programs and/or services running on the device against the programs and/or services allowed by the at least one of the plurality of policies, and based on the comparison, determining that the device is running at least one program and/or service disallowed by the at least one policy. Further, the method includes in response, prohibiting access of the device to the network.