The Dyson MQTT server (2022 and possibly later) allows publications and subscriptions by a client that has the correct values of AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN, and device serial number, even if a device (suc…

Overview

The Dyson MQTT server (2022 and possibly later) allows publications and subscriptions by a client that has the correct values of AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN, and device serial number, even if a device (such as a Pure Hot+Cool device) has been removed and is not visible in the supported MyDyson app. This could allow an unexpected actor to obtain control and set the room temperature (up to 37 Celsius) if ownership of the device is transferred without wiping the device. NOTE: the Supplier's position is that this is a potential vulnerability that dates back 4 years ago in 2022 and "we are unable to replicate that anymore." Based on the submitted report, in order to leverage this issue, an attacker needs to own a Dyson device with full privileges, sniff for the AWS credentials, and then transfer ownership of that Dyson device to the victim. Even if these steps were successfully accomplished, the attacker only acquires the ability to configure the Dyson device within its safe operating range, and does not acquire the ability to execute code on the device or obtain sensitive information.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.