I think your issue is still Protected Management Frames which appear mandatory in 802.11ac. See 802.11w protected management frames - Wi-Fi

but this AP does not support PMF

Specifically: "The IEEE 802.11w amendment added this functionality to the 802.11 standard and since July 1st 2014, the Wi-Fi Alliance (WFA) made the support of Protected Management Frames (PMF) mandatory to pass 802.11ac or Passpoint aka HotSpot2.0 R2 interoperability certification. So we will see a much greater adoption of this feature in the near future."

Source

I am curious how you know it doesn't support it, is that due to it not referencing it in the admin interface or from the frames it's sending out? You should be able to confirm this by checking the packets coming from the AP and looking for the presence of the bit identifying PMF support.

Also slight technicality but the attack used to work as the wireless clients believed they had been disassociated by the AP, not the other way around.

TL;DR: De-authentication frames are now signed using the wireless key because of something called "PMF" which is mandatory to pass 802.11ac certification. Your AP probably supports PMF without you realising.

I think your issue is still Protected Management Frames which appear mandatory in 802.11ac. See 802.11w protected management frames - Wi-Fi

but this AP does not support PMF

Specifically: "The IEEE 802.11w amendment added this functionality to the 802.11 standard and since July 1st 2014, the Wi-Fi Alliance (WFA) made the support of Protected Management Frames (PMF) mandatory to pass 802.11ac or Passpoint aka HotSpot2.0 R2 interoperability certification. So we will see a much greater adoption of this feature in the near future."

Source

I am curious how you know it doesn't support it, is that due to it not referencing it in the admin interface or from the frames it's sending out? You should be able to confirm this by checking the packets coming from the AP and looking for the presence of the bit identifying PMF support.

Also slight technicality but the attack used to work as the wireless clients believed they had been disassociated by the AP, not the other way around.

TL;DR: De-authentication frames are now signed using the wireless key because of something called "PMF" which is mandatory to pass 802.11ac certification. Your AP probably supports PMF without you realising.

I think your issue is Protected Management Frames which appear mandatory in 802.11ac. See 802.11w protected management frames - Wi-Fi

Specifically: "The IEEE 802.11w amendment added this functionality to the 802.11 standard and since July 1st 2014, the Wi-Fi Alliance (WFA) made the support of Protected Management Frames (PMF) mandatory to pass 802.11ac or Passpoint aka HotSpot2.0 R2 interoperability certification. So we will see a much greater adoption of this feature in the near future."

Source

TL;DR: De-authentication frames are now signed using the wireless key because of something called "PMF" which is mandatory to pass 802.11ac certification.

I think your issue is still Protected Management Frames which appear mandatory in 802.11ac. See 802.11w protected management frames - Wi-Fi

but this AP does not support PMF

Specifically: "The IEEE 802.11w amendment added this functionality to the 802.11 standard and since July 1st 2014, the Wi-Fi Alliance (WFA) made the support of Protected Management Frames (PMF) mandatory to pass 802.11ac or Passpoint aka HotSpot2.0 R2 interoperability certification. So we will see a much greater adoption of this feature in the near future."

Source

I am curious how you know it doesn't support it, is that due to it not referencing it in the admin interface or from the frames it's sending out? You should be able to confirm this by checking the packets coming from the AP and looking for the presence of the bit identifying PMF support.

Also slight technicality but the attack used to work as the wireless clients believed they had been disassociated by the AP, not the other way around.

TL;DR: De-authentication frames are now signed using the wireless key because of something called "PMF" which is mandatory to pass 802.11ac certification. Your AP probably supports PMF without you realising.