Power save, or power save attack?
Last Post: July 21, 2010:
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In order to pull this off, you'd have to set the following parameters in the beacon:
- Beacon interval (Set to maximum (16 bit field, max value 65536)) (keep in mind that vendors may not allow that value)
- DTIM Interval (Set it to maximum (8 bit field, max value 256)) (keep in mind that vendors may not allow that value)Beacon interval is in TU's (Time Units) which is a kilo microsecond (1024 microseconds, which is just a bit over a millisecond.
To get the maximum number of seconds between beacons, we take max beacon interval multiplied by a kilo-microsecond (1024 us) = 67,108,864 microseconds or about 67 seconds.
Now, take the max DTIM interval of 256. So, every 256th Beacon is a DTIM. Since a beacon is now only happening every 67 seconds, it would take 17152 minutes (285 hours) between DTIMs (when a STA wakes to receive).
So, in theory, it would cause a DoS for 285 hours UNLESS the STA had something to Tx. If it ever woke to Tx anything, then it would more than likely hear a legitimate beacon and use the proper data, in which case you'd have to retransmit your fake beacon.
In all reality, there are dozens of ways to perform a DoS on a Wi-Fi network. This one is neat like many, but I prefer a jammer. :)
GT
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