In one embodiment, an elimination point device in a network obtains a master secret from a network controller. The elimination point device assesses, using the master secret, whether an incoming packet received by the elimination point device from a redundant path between the elimination point device and a replication point device in the network includes a valid message integrity check (MIC). The elimination point device determines whether the incoming packet was injected maliciously into the redundant path, based on the assessment of the incoming packet. The elimination point device initiates performance of a mitigation action in the network, when the elimination point device determines that the incoming packet was injected maliciously into the redundant path.