It is call ed a false trigger and can happen when you run an anti-virus program while playing the game.
Anti-virus programs have no clue what a data packet is intended for. Game packets look like garbage to an anti-virus program and occasionally a data packet can have a pattern which resembles a virus, and then the amti-virus false-triggers, blocking that packet.
It is not a virus. it is just a game data packet which has a similar pattern as a virus.