“Under the door” attack means that the attacker hooks the internal handle from below through the sliding tool under the door, and then pulls the handle downward to open the door. This attack acts on the common Hotel doors and locks. Turning the handle from the inside always causes the door to open. [Michal Jirk ů] I found myself in a hotel room with a big gap under the door, so I decided to quickly design and print a guard to prevent such attacks.
This is a simple object that can be deployed with only 20 minutes of printing and a little double-sided tape. Because the under door attack performed by the attacker has a considerable mechanical disadvantage, it does not take much time to defeat the attempt, which is what the object does. After all, the personal safety of the hotel is particularly important, and it is known that cheaters will use known vulnerabilities to attack, such as wearing a bad onity key card lock on their face.
If you can’t imagine how all this works, this video will demonstrate an attack under the door, so you can see that blocking the space with the handle will easily prevent the tool from reaching the desired position.