Violations (Star Trek: Voyager)

Violations is the fourth book in the main Star Trek Voyager series.
==Book Description==
Under the guise of helping the crew find a way home, a group of aliens board the U.S.S. Voyager, and then steal the main computer. To get it back, Captain Janeway is forced to negotiate with the thieves -- who are from a consortium of planets where thievery is a way of life. But as Janeway and the crew fight to retrieve their computer in time to save the barely functioning ship, they become embroiled in a political battle that could not only destroy the "U.S.S. Voyager," but the crew as well.
(Description from Amazon.com)