How Large is the Security Threat from "Air-Gapped" Computers?

In environments where networks or devices are rated to handle different levels of classified information, the two disconnected devices/networks are referred to as "low side" and "high side", low being unclassified and high referring to classified, or classified at a higher level. This is also occasionally referred to as red (classified) and black (unclassified). To move data from the high side to the low side, it is necessary to write data to a physical medium, and move it to a device on the latter network. Traditionally based on the Bell-La Padula Confidentiality Model, data can move low-to-high with minimal processes while high-to-low requires much more stringent procedures to ensure protection of the data at a higher level of classification.

Air-gapped computers are isolated — separated both logically and physically from public networks — ostensibly so that they cannot be hacked over the Internet or within company networks. Researchers at the Ben-Gurion University of the Negev (BGU) Cyber Security Research Center have discovered that virtually any cellphone infected with a malicious code can use GSM phone frequencies to steal critical information from infected “air-gapped” computers. Just how serious is the "air-gapped" computer threat? Send us your comments here at the Cloud and Cyber Security Center.