Yoics: account takeover vulnerability

Yoics market themselves as "secure cloud networking" and is a service that allows you to "Internet access (almost) anything". Many top brands use Yoics in their devices; Cisco, Astak, Philips and more. A good example is the Philips In.Sight M100 Wireless Home Monitor.

It was possible for an attacker to manipulate the API call used for password resets and reset the password to any account, providing they know the users e-mail address.

Let's take a look at the raw HTTP requests.

To begin the password reset process we first get the security question that we need to answer:

GET /web/api/user.ashx?key=PhilipsAndroid&email=6140622e636f6d&action=getsecurityquestion&type=xml  

The email field is just the e-mail address hex encoded. The call simply returns the security question: <passwordquestion>Favorite Pet's Name</passwordquestion>

To complete the password reset process we send another HTTP request with the answer:

GET /web/api/user.ashx?key=PhilipsAndroid&email=6140622e636f6d&answer=626f62&skipemail=no&action=recoverpassword&type=xml HTTP/1.1  

Again, the answer parameter is just hex encoded. If the answer is wrong we get back a simple error message. All is good.

After trying various different combinations I noticed if you ommit the answer parameter entirely you get a <status>ok</status> message. Has it been reset? A few minutes later I received the standard password reset e-mail. Hmm, I wonder... Let's try setting the skipemail parameter to yes:

GET /web/api/user.ashx?key=PhilipsAndroid&email=6140622e636f6d&skipemail=yes&action=recoverpassword&type=xml HTTP/1.1  

And the response:


Wham, bam, thank you ma'am. From here an attacker can login with the given password and access the the users IoT devices remotely.

Responsible Disclosure

  • 27/01/2015 - Initial contact made with vendor.
  • 29/01/2015 - Vendor confirmed the bug and will fix as a priority (within 24 hours).
  • 30/01/2015 - Patch is live in production. Confirmed fixed.