A modified wireless transmission that bypasses all installation approvals and safety checks of the receiving ship, as best as it can, ignoring firewalls and security measures. This means that only especially hardened ships (such as capitals or other ECM/EW suite ships) can 100 percent effectively nullify the transmission. Other ships... I guess it would be dependent on how quickly someone picks up on what is going on, and their ability to lock it down before the virus can get to any of it's target systems. Of course, if the full electronic firepower of the Ljus was unleashed at a single ship, something would go down at least temporarily.