While doing some troubleshooting, I noticed that firmware updates are downloaded via insecure HTTP from update.purpleair.com - this should really use SSL at a minimum. The fw currently seems to have SSL support in it already, as it posts data updates to www.purpleair.com from what I was able to see in the logs.
Thanks for all the work y’all do!
Firmware images will need to be downloadable from http in order to support older sensors updating to newer firmware. However, updating the firmware to use HTTPS for firmware updates is something we can look into.
Makes sense. Does the firmware already checksum (SHA256 or similar) the download in some way? If you were able to get the checksum securely, then at least that would make it an order of magnitude harder for someone to compromise the integrity of the HTTP download.
Interested in the answer to this, too. Thanks for bringing it up!