I was wondering, how safe the default configuration of a Fritz!Box really is.
By default, there is a 16 digit WPA2 key, which contains only numbers.
My first though was, that bruteforcing is right easy, because it only containes numbers.

I could find out, it'll take up to 65 years with my Geforce 780 to bruteforce.

Now I am wondering, if it's possible to have rainbow tables, in order to crack it? I don't understand rainbow tables that well to imagine the time to create them, or the size.

Maybe somebody can help me understand it some more.



As for rainbow tables regarding the 16 lenght number default password on FritzBox , YES, if somebody had them already made, you could calculate for your FritzBox if it has a default password or no (all possibilities, 16 numbers). But as regarding to MAKE a rainbow-table for 16lenght numbers for FritzBox, it would take 63 years (same time as dictionary attack or even a bit slower) and some PB , thousnds and thausends of TB of space. But yes, if anyone would make a rainbowtable with some super-computer and store it on his super-drive, it would work for all future probes (ofcourse only with same ESSID (wlan NAME) , for example only for "Fritz!Box FON Wlan 7390". For EVERY ESSID you would have to make a new rainbow table. In practice, I higlhly doubt that anyone has a rainbow table for any of Fritz!Box which include all default WPA's (16 lenght numeric key).

If I were you, I would try to calculate the algorithm, with which they (the factory) calculate the default WPA key. You can find at least a dozen of FORUMs, WIKIs etc (most in German) ,where they are trying to calulate the secret, from which the factory calculates the default WPA keys for their boxes. As I understood , the calculate them from the MAC (every box has more than 1 MAC, one for WLAN, one for ETH, itd. , from serial number, and from default ESSID. Good luck decrypting the alghoritm.

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