Star Trek: Every Auxiliary Craft Explained
3. Attack Fighters
Although most Starfleet vessels were not designed primarily for combat, there were exceptions. Of course, the Defiant was created to fight the Borg threat, but Starfleet also produced attack fighters for large-scale conflicts.
These fighters were about the size of a runabout (halfway between a shuttle and a typical starship) and Issue 68 of Star Trek: The Official Starships Collection listed it's maximum speed at an incredibly fast warp 9, with a crew complement of only 2. They were used frequently in battles during The Dominion War, and some were even stolen and upgraded by the Maquis, who used them to fight back against the Cardassians.
Attack fighters didn't typically engage hostiles on their own, instead relying on support from a fleet of starships like we saw in the DS9 episode Sacrifice Of Angels, which is why we're including them here as auxiliary craft.