Defeating the Kaba Simplex Mechanical 5-Button Lock

The Kaba Simplex 5-button, mechanical combination lock is used to control access to areas requiring medium security, but involving high enough traffic so that issuing keys in impractical. These locks are often used in corporate and government facilities.

Kaba Simplex are good quality locks, but they can be easily bypassed if you have several minutes to input combinations.

Older versions of this lock could be opened by placing a strong magnet on the side of the lock, as can be seen in this YouTube video:  Kaba Simplex Door Combination Lock Defeated w/Sparrows "MAGNETO". When made aware of this vulnerability, Kaba Simplex upgraded their locks, replacing the part affected by the magnetic with material that isn't so affected. Still, there are a lot of older locks still in use and this bypass is worth a try.

Assuming that the magnetic bypass doesn't work, you can simply run through all possible combinations. When setting a combination on a Kaba Simplex 5-button mechanical lock, you can use one button or all five for a combination, but each button can only be used once. You can also depress two or more buttons simultaneously as a step in the combination.

In most cases users set some combination of two or three numbers when using these locks, and you will often find the combination within the following 180 combinations. (Is your Simplex combination on this list?)

 

You could probably try all of the above combinations within just a few minutes. But, because you could use any number of buttons between zero (no combination) and five when setting your lock combination; the total number of possible combinations then is 1082:

 

Buttons Used          Possible Combinations

     0                                  1

     1                                  5
     2                                  30
     3                                  130
     4                                  375
     5                                  541

               Total 1082

 

You can find the complete list of Simplex combinations at various sites on-line. Trying all possible combination would take a bit of time, but you will probably find the correct combination well before you exhaust all of the possible combinations. Also you wouldn't have try all of the combinations at once if you can gain repeated access to the lock.  

 

So, to defeat the Kaba Simplex Mechanical 5-Button Lock, try bypassing the lock with a magnet if it is an older lock. Next, try the 180 most common combination highlighted above. If this fails, you will have to work through each combination, but this will get you into the lock, in less than a couple of hours. 

--