Security researchers form Mcafee observed two different scenario’s, in the first scenario attackers, can force Microsoft Edge browser to navigate to the URL hosted in attacker’s server, with the second case an attacker can use limited Version IE browser with the victim credentials and impersonate as a victim.
Cortana Vulnerability – Edge
With the first scenario, the privilege escalation vulnerability allows an attacker to force navigation the locked screen and all the attacker needs to have a physical access to the device and this vulnerability does not allow an attacker to unlock the system.
Cortana is a virtual personal assistant and brings the search results to form the Bing, researchers spotted the links offered are clickable even though the device is locked. This allows an attacker to force navigation to a website.
To accomplish this researcher’s registered the available domain that pointed in the website link and asked Cortana to search for “Miss Aruba” with the locked device and the Cortana retrieves the result. With the appeared results the links appeared to be clickable.
By clicking the link they observed the Edge browser retrieves the content even though the device remains in the locked state.
“This attack could occur at a coffee shop, retailer, bank, or against targeted individuals. This configuration is the default on Windows, and our research has shown that many users never disable Cortana from the lock screen.”
Cortana Vulnerability – Internet Explorer
With the system locked researchers asked “Hey Cortana, I want to sell my house” based on the query it offers the results for Real Estate Search and Haunted house.
“One potential attack scenario arises if a corporation offers a mechanism to reset Windows credentials via a web server but does not require users to re-enter the old password. One could simply navigate to the reset link, input a new password, exit the limited navigator, and unlock the device with the newly set password, all from a locked computer.”
Both of the new flaws have been fixed with the Microsoft’s August update, the best mitigation is to turn off Cortana on the lock screen.