If you have a service contract (SmartNet) associated with your Cisco account, you can download software directly from the Cisco Support & Downloads page.
(Virtual IOS) changed the landscape by allowing the actual Cisco operating system code to run on a hypervisor (using QEMU/KVM). This specific image provides Advanced Enterprise download viosadventerprisek9mspa1593m6qcow2 verified
For the specific 15.9(3)M6 image, the verified MD5 is 49a6977977263b2774bebc56e4e678ff . Official & Verified Download Methods If you have a service contract (SmartNet) associated