The attacks, which are ongoing, were particularly effective on the night of 1 November, 2004, said Paller, who outlined how the hackers first scanned then broke into US government computers. At 22:23(PST) the Titan Rain hackers exploited vulnerabilities at the US Army Information Systems Engineering Command at Fort Huachuca, Arizona. A few hours later, at 01:19(PST), they exploited the same hole in computers at the Defense Information Systems Agency in Arlington, Virginia.