The sale of weapons to North Korea by other states is prohibited by UN sanctions, and the KPA's conventional capabilities are limited by a number of factors including obsolete equipment, insufficient fuel supplies and a shortage of digital command and control assets. To compensate for these deficiencies, the KPA has deployed a wide range of asymmetric warfare technologies including anti-personnel blinding lasers, GPS jammers, midget submarines and human torpedoes, stealth paint, and cyberwarfare units. In 2015, North Korea was reported to employ 6,000 sophisticated computer security personnel in a cyberwarfare unit operating out of China. KPA units were blamed for the 2014 Sony Pictures hack and have allegedly attempted to jam South Korean military satellites.