The computer worm was a computer program that replicates itself onto other computers. It can be used as a software weapon. Unlike a computer virus, a worm does not need to attach itself to an existing program. During a briefing for a Starfleet Intelligence mission, Lieutenant Stephen Klisiewicz gave a red data card to Starfleet Intelligence agent Bridget McLellan. This card contained a computer worm that would erase the sensor data from the damaged Orion freighter Treana that was in custody of the Gorn Hegemony in 2268.