Summary: Counterfeit security badges and credentials are readily available for sale on the Internet and other public sources and could be used by criminals, terrorists, and foreign spies to gain access to secure government buildings and airports. GAO's undercover agents acquired fictitious law enforcement badges and tried to gain access to secure government facilities. These agents were 100 percent successful in penetrating 19 federal sites and two commercial airports. GAO entered 18 of the 21 sites on its first attempt; the other three sites required a second visit before GAO was able to penetrate them. At no time during the undercover visits were the GAO agents' bogus credential or badges challenged by anyone. At the 21 sites that GAO's undercover agents successfully penetrated, they could have carried in weapons, listening devices, explosives, or chemical and biological agents. Sixteen of the sites GAO visited contained the offices of cabinet secretaries or agency heads. At 15 of these sites, GAO's undercover agents were able to reach the entry to the suites of the cabinet secretary or agency head. At 15 of the sites, GAO's agents entered a restroom near these offices and could have left a valise containing weapons or explosives without being detected. At a federal courthouse, GAO's agents were waved through a magnetometer but not screened. A briefcase that one agent carried went unchecked. The agents were escorted to a gunroom, which they were allowed to enter alone. They were then told to lock their weapons, but no one supervised the actual surrender of the agents' weapons. At the two airports GAO visited, the agents declared themselves to be armed law enforcement officers and displayed their fake badges and identification. The agents were issued law enforcement' boarding passes at the ticket counter. The agents then presented themselves at security checkpoints and were waved around the magnetometers. Neither the agents nor their valises were screened.