Spooks (2002)

S2E3 Spiders

MI5's central system has fallen victim to a cyber attack. Tom and his team believe they might have a breakthrough with an I.T. teacher as a suspect. To gather intel, Zoe goes undercover to infiltrate his world and uncover what he knows. Time is of the essence as they race to thwart the hacker's plans before sensitive information about every agent is exposed.