Possible PTK compromission after GTK rekeying

Jouni Malinen j
Sat Nov 16 06:35:12 PST 2013

On Fri, Nov 15, 2013 at 04:28:47PM +0100, Antonio Quartulli wrote:
> I am running hostapd-20120428 on OpenWrt and it is exhibiting a strange
> encryption issue (I am using wpa mixed mode: WPA/WPA2).
> The symptom is that some Windows clients are losing their connectivity
> after a GTK refresh (often after the first, but not necessarily).

Which driver are you using? Can you provide a capture file from a test
run with keys that you can share?

> From an high level point of view it looks like the GTK rekeying is somehow
> breaking the PTK on hostapd so that outgoing packets are not encrypted properly
> anymore.

I'd look at the driver first..

Jouni Malinen                                            PGP id EFC895FA

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