# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one # or more contributor license agreements. Licensed under the Elastic License # 2.0; you may not use this file except in compliance with the Elastic License # 2.0. # Name: RunDLL32 Javascript Callback # RTA: rundll32_javascript_callback.py # signal.rule.name: Local Service Commands # signal.rule.name: Potential Modification of Accessibility Binaries # ATT&CK: T1085 # Description: Executes javascript code with an AJAX call via RunDll32.exe from . import common from . import RtaMetadata metadata = RtaMetadata( uuid="75687622-2e75-4612-b213-a31f923efdd4", platforms=["windows"], endpoint=[], siem=[], techniques=[] ) @common.requires_os(*metadata.platforms) def main(): common.log("RunDLL32 with Javascript Callback") server, ip, port = common.serve_web() common.clear_web_cache() url = "http://%s:%d" % (ip, port) rundll32 = "rundll32.exe" js = """ 'javascript:"\..\mshtml,RunHTMLApplication ";' 'var%20xhr=new%20ActiveXObject("Msxml2.XMLHttp.6.0");,' 'xhr.open("GET", "{url}",false);xhr.send();' """.format( url=url ) packed_js = "".join(s.strip() for s in js.splitlines()) common.execute([rundll32, packed_js]) server.shutdown() if __name__ == "__main__": exit(main())