An exploitable firmware downgrade vulnerability exists in Insteon Hub running firmware version 1013. The firmware upgrade functionality, triggered via PubNub, retrieves signed firmware binaries using plain HTTP requests. The device doesn't check the firmware version that is going to be installed and thus allows for flashing older firmware images. To trigger this vulnerability, an attacker needs to impersonate the remote server 'cache.insteon.com' and serve any signed firmware image.