JavaScript/JScript

Adversaries may abuse JavaScript and/or JScript for execution. JavaScript (JS) is a platform-agnostic scripting language (compiled just-in-time at runtime) commonly associated with scripts in webpages, though JS can be executed in runtime environments outside the browser.

Jscript is the Microsoft implementation of the same scripting standard. JScript is interpreted via the Windows Script engine and thus integrated with many components of Windows such as the Component Object Model and Internet Explorer HTML Application (HTA) pages.

Adversaries may abuse JavaScript / Jscript to execute various behaviors. Common uses include hosting malicious scripts on websites as part of a Drive-by Compromise or downloading and executing these script files as secondary payloads. Since the payloads are text-based, it is also very common for adversaries to obfuscate their content as part of Obfuscated Files or Information.

Example: