Global, location-aware security information is generated, and used to provide location-aware computer security to portable computing devices. A global, location-aware security system receives local, location-aware security information from a large number of portable devices. The local information from each device comprises their locations at the times of detection of threat indicators. The global system transforms the received local information into global information, and maps detected threat indicators to specific locations. Each device monitors activity occurring thereon, detects threat indicators and current locations, and builds local information, which is periodically transmitted to the global system. When a device is activated or moved to a new location, it determines its current location, and requests global information concerning that location from the global system. The global system transmits global information, which the portable device uses to apply a location-based risk level policy to provide location-aware computer security.