Technologies are described herein for scanning machine images using a scanning service to identify potential risks. The scanning service may be associated with a service provider network. A scan request is received at the scanning service that requests machine images to be scanned. One or more scans may be performed on each of the machine images. An execution environment may host a machine image during a scan of the machine image. Scan result data associated with the scans is stored. The scan result data may be used to provide scan results to the requestor.