Prior to 2018-04-27, the reprompt feature in Amazon Echo devices could be misused by a custom Alexa skill. The reprompt feature is designed so that if Alexa does not receive an input within 8 seconds, the device can speak a reprompt, then wait an additional 8 seconds for input; if the user still does not respond, the microphone is then turned off. The vulnerability involves empty output-speech reprompts, custom wildcard (gibberish) input slots, and logging of detected speech. If a maliciously designed skill is installed, an attacker could obtain transcripts of speech not intended for Alexa to process, but simply spoken within the devices hearing range. NOTE: The vendor states Customer trust is important to us and we take security and privacy seriously. We have put mitigations in place for detecting this type of skill behavior and reject or suppress those skills when we do. Customers do not need to take any action for these mitigations to work.
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Echo_show_firmware | Amazon | * | 2018-04-27 (excluding) |
Such a scenario is commonly observed when:
In the generic exploit of session fixation vulnerabilities, an attacker creates a new session on a web application and records the associated session identifier. The attacker then causes the victim to associate, and possibly authenticate, against the server using that session identifier, giving the attacker access to the user’s account through the active session.