Instead of risking malware, here are three to get a working El Capitan 10.11.6 bootable system. Note: Two methods do not give an ISO directly but produce an equivalent bootable USB.
System Requirements: OS X El Capitan 10.11. File Size: 1.5 GB. Download. This update is recommended for all OS X El Capitan users. Apple Support Mac OS X 10.11 El Capitan : Apple.Inc - Internet Archive May 2, 2567 BE — mac os x el capitan 1011 6 iso download gratis work