Analyzing the ACK Counterfeiting Attack in Delay and Disruption Tolerant Networks

The routing protocols proposed for Delay and Disruption Tolerant Networks (DTNs) often employ acknowledgements. The goal is to increase the available space in buffers and also to avoid messages from being dropped unnecessarily due to buffer overflow. Protocols that employ such technique, however, are prone to suffer with from the acknowledgement counterfeiting attack. In this attack, malicious nodes counterfeit acknowledgements in order to force legitimate nodes to drop messages that are not already delivered to destination. Thus, the network performance is degraded. In this work, we analyze a countermeasure for this attack, in which nodes ignore acknowledgements for messages that were not previously received by this node. Three real mobility traces and a well-known mobility model are used in simulations and results show that when approximately 12% of the nodes in the network are malicious, the message delivery rate decreases up to 61 percentage points.