3 ms·

This reminded me of this explanation of how MacBooks (and presumably other devices) manage to reconnect to Wifi so quickly after waking from sleep: http://cafbi

by bfirsh 10y ago

This reminded me of this explanation of how MacBooks (and presumably other devices) manage to reconnect to Wifi so quickly after waking from sleep: http://cafbit.com/entry/rapid_dhcp_or_how_do http://cafbit.com/entry/rapid_dhcp_or_how_do

digi_owl 10y ago
And in the process walking all over various security best practices? And was there not a similar security snafu involving iPhones broadcasting past ssids every time they tried to connect to a access point?
- icebraining 10y ago
  Well, this traffic is sent after link establishment, so at least in a WPA network, it's already encrypted (hopefully it doesn't do the same in unencrypted networks). Still, any member of the network could sniff the MACs of the last few APs the device was connected to, which as you said, it's a security/privacy leak.
- kiliankoe 10y ago
  Don't most (mobile) devices broadcast all known SSIDs just in case a network is available and hidden? I don't really know a lot about the subject matter, but as I recall this does not apply to just iPhones. I also remember an installation at the Datenspuren in Dresden with a monitor showing all of these SSIDs it intercepted with people walking past and being astounded how the device knew their home network name^^
  - ycmbntrthrwaway 10y ago
    Almost all Android devices do the same, they just send probe requests with all known networks. That is why you can automatically connect to "hidden" networks. Just run kismet or wireshark and see for yourself.
    - BoorishBears 10y ago
      And it can be used to uniquely identify devices and track them with fairly standard hardware
      - epistasis 10y ago
        Doesn't a MAC address get broadcast anyway? Unless wifi devices are randomizing their MAC addresses that seems like a fairly trackable thing.
        nitrogen 10y ago
        IIRC newer iOS devices do randomize the MAC address used for probes.
- deleted 10y ago
  [deleted]

by bfirsh 10y ago

digi_owl 10y ago

And in the process walking all over various security best practices? And was there not a similar security snafu involving iPhones broadcasting past ssids every time they tried to connect to a access point?

icebraining 10y ago
Well, this traffic is sent after link establishment, so at least in a WPA network, it's already encrypted (hopefully it doesn't do the same in unencrypted networks). Still, any member of the network could sniff the MACs of the last few APs the device was connected to, which as you said, it's a security/privacy leak.
kiliankoe 10y ago
Don't most (mobile) devices broadcast all known SSIDs just in case a network is available and hidden? I don't really know a lot about the subject matter, but as I recall this does not apply to just iPhones. I also remember an installation at the Datenspuren in Dresden with a monitor showing all of these SSIDs it intercepted with people walking past and being astounded how the device knew their home network name^^
- ycmbntrthrwaway 10y ago
  Almost all Android devices do the same, they just send probe requests with all known networks. That is why you can automatically connect to "hidden" networks. Just run kismet or wireshark and see for yourself.
  - BoorishBears 10y ago
    And it can be used to uniquely identify devices and track them with fairly standard hardware
    - epistasis 10y ago
      Doesn't a MAC address get broadcast anyway? Unless wifi devices are randomizing their MAC addresses that seems like a fairly trackable thing.
      - nitrogen 10y ago
        IIRC newer iOS devices do randomize the MAC address used for probes.
deleted 10y ago
[deleted]