XcodeGhost (and variant XcodeGhost S) are modified versions of Apple's Xcode development environment that are considered malware. The software first gained widespread attention in September 2015, when a number of apps originating from China harbored the malicious code. It was thought to be the "first large-scale attack on Apple's App Store", according to the BBC. The problems were first identified by researchers at Alibaba, a leading e-commerce firm in China. Over 4000 apps are infected, according to FireEye, far more than the 25 initially acknowledged by Apple, including apps from authors outside China.