Identify interface and processes that interferes with hcxdumptool:

$ hcxdumptool -I
wlan interfaces:
MAC_INTERFACE  <wlan_interface> (used_driver)

On a warning like this, stop services:
warning: NetworkManager is running with pid 415
warning: wpa_supplicant is running with pid 515
stop this processes:
$ sudo systemctl stop NetworkManager.service
$ sudo systemctl stop wpa_supplicant.service

Check driver
$ sudo hcxdumptool -i <wlan_interface> --check_driver
starting driver test...
driver tests passed - all required ioctl() system calls are supported by driver
restoring old driver settings

Check that packet injection is working (run it at least 13 * 5 seconds):
$ sudo hcxdumptool -i  <wlan_interface> --do_rcascan
INFO: cha=6, rx=351, rx(dropped)=0, tx=47, err=0, aps=21 (13 in range)

if the values increase and APs are in range, start the attack:
$ hcxdumptool -i <wlan_interface> -o test.pcapng --enable_status=1
otherwise hcxdumptool will inform you that packet injection is not working as expected.

If attack finished and hcxdumptool terminated, restart services
$ sudo systemctl start NetworkManager.service
$ sudo systemctl start wpa_supplicant.service

If hcxdumptool is not able to set monitor mode for example on this driver:
https://github.com/aircrack-ng/rtl8188eus
run ip link and iw first - than run hcxdumptool:
$ sudo ip link set <wlan_interface> down
$ sudo iw dev  <wlan_interface> set type monitor
$ sudo ip link set  <wlan_interface> up
$ sudo iw dev  <wlan_interface> info


Most (nearly all) occurring issues are related to the driver (driver doesn't support monitor mode and
full packet injection) and the system configuration (running services that take access to the interface).
The driver of the device must support both: monitor mode and full packet injection!
Otherwise hcxdumptool will fail!

Some of the issues are fixed:
https://bugzilla.kernel.org/show_bug.cgi?id=202241
https://bugzilla.kernel.org/show_bug.cgi?id=202243
https://github.com/openwrt/mt76/issues/2...-500999516

Some of them are partly fixed (or somebody is working on them):
https://github.com/aircrack-ng/rtl8812au/issues/376

Some of them are not fixed, yet:
https://bugzilla.kernel.org/show_bug.cgi?id=202541

Unfortunately many, many drivers do not support monitor mode and full packet injection. Get more information here:
https://wikidevi.com/wiki/Main_Page
