Personally, I agree with your advice to customers.

 

Supposedly it’s a way to connect devices to WiFi without entering (or knowing) 
the WiFi password.  Some annoying devices like cheap printers almost force you 
to use WPS.

 

From: AF <af-boun...@af.afmug.com> On Behalf Of Adam Moffett
Sent: Saturday, March 22, 2025 4:37 PM
To: AnimalFarm Microwave Users Group <af@af.afmug.com>
Subject: Re: [AFMUG] math is fun?

 

I never looked into how WPS was supposed to work.  I pushed the button once and 
the Internet broke.  I went into the router and reset the WPA key and went 
about my business.  I advised all customers that the WPS button breaks 
everything and please never touch it. 

What were you supposed to do with WPS?

 

On Sat, Mar 22, 2025 at 3:24 PM Ken Hohhof <khoh...@kwom.com 
<mailto:khoh...@kwom.com> > wrote:

OK, 74 years on this planet and 1 brain aneurysm have taken their toll and I 
can’t do math in my head like I used to.  (Ask me how I know “person, man, 
woman, camera, TV” isn’t an IQ test).

 

But I still find this a fun math problem, and the math is actually pretty 
basic.  I wonder how many kids today know there are 10^8 possible 8 digit 
numbers, and that 10^8 is 100 million.  And how many would say math can be fun. 
 I grew up during the Cold War and the Space Race … math and science were 
actually cool.

 

Anyway, to get WiFi Alliance certification and put the WIFI Certified logo on 
your router, it has to support WPS (WiFi Protected Setup), including both the 
button press method and the PIN method.  The PIN method is a security problem.  
In theory, a brute force attack would have to guess an 8 digit number, so 10^8 
= 100 million tries (worst case).  That’s gonna take a long time.

 

Unfortunately, there is a flaw in the algorithm, as stated in this 14 year old 
CERT advisory.  An attacker can tell when they have guessed the first 4 digits 
correctly, so 10^4 = 10,000 tries.  Then all that remains is to guess the last 
4, but the 8th digit it a parity check, so you only have to guess 3 more 
digits.  10^3=1,000 more tries, for a total of 11,000.

 

https://www.kb.cert.org/vuls/id/723755

 

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