Cyber Flag 21-1 United Kingdom defensive cyber operators test their skills and ability to detect enemy presence, expel it, and identify solutions to harden simulated networks alongside international partners from 23 countries during U.S. Cyber Command's Cyber Flag 21-1 exercise. SHARE: Download: Full Size (0.65 MB) Credit: Photo courtesy of U.S. Cyber Command VIRIN: 211118-N-KT462-3558M.JPG Photo Gallery