Re: [Mud] [OPSAWG] putting quarantined IoT devices behind a captive portal

[John Romkey <[e-mail]>]

> On Jul 9, 2019, at 5:49 PM, Michael Richardson <[e-mail]> wrote:
> 
> 
> Eliot Lear <[e-mail]> wrote:
> 
>>> to retrieve a JSON object telling it that it is captive. At which point, it
>>> can flash a LED, or attempt a firmware upgrade, or maybe just reboot if a
>>> timer goes off.  (%)
> 
>> You are suggesting that a device self-remediate.  Some devices may be
>> able to eventually do that, but I have my doubts.  Were I a hacker, I
>> would have the device pretend to do just that.  And so this ties
>> somewhat to RATS.  I think a MUD extension might be able to help in as
>> much as one could imagine a “remediation” recommendation.
> 
> Yes, so a full attack on the IoT device would do what you describe.
> A partial attack might miss messing this.  A reboot might clear out the
> malware, or might mitigate it enough (such as going to boot firmware) that
> would permit new firmware to be loaded.
> 
> Yes, getting completely out of the quarantine would require either
> attestation or human intervention.  But, if the device now has good firmware,
> it would be able to send the "please unquarantine me" signal.

I believe strongly that the only safe thing you can do with a device that’s been in any way compromised is completely isolate it.It shouldn’t be able to send an “unquarantine” signal. You shouldn’t even try to talk to it.

Let the firewall which is implementing MUD notify the user about the problem. Let the device’s app or cloud services notify the user that the device is offline. Possibly in a later evolution of MUD the firewall might have a way to notify the device’s cloud service, but I wouldn’t hamstring the initial version of MUD with an attempt to do that.
	- john romkey
	https;//romkey.com <http://romkey.com/>