Methods and systems for Data Leak Prevention (DLP) in an enterprise network are provided. According to one embodiment a data leak protection method is provided. Information regarding a watermark filtering rule is received by a network device. The information includes a sensitivity level and an action to be applied to files observed by the network device that match the watermark filtering rule. A file attempted to be passed through the network device is received by the network device. A watermark embedded within the received file is detected by the network device. A sensitivity level associated with the watermark is compared by the network device to the sensitivity level of the watermark filtering rule after the watermark is detected. If the comparison results in a match, then the action specified by the watermark filtering rule is performed by the network device.