Malware
PeckBirdy
According to Trend Micro, PeckBirdy is a script-based framework which, while possessing advanced capabilities, is implemented using JScript, an old script language.
PeckBirdy is a JavaScript malware family.
Background
Trend Micro reports that PeckBirdy is a script-driven framework that, despite its sophisticated feature set, is built in JScript, a dated scripting language. The choice lets the framework run across varied execution environments through LOLBins (Living off the land binaries). That versatility enabled PeckBirdy to serve at multiple points in the kill chain: as a watering-hole control server in the initial attack phase, a reverse shell server during lateral movement, and a C&C server in the backdoor phase.
Source: Malpedia (Fraunhofer FKIE).