Sacpy does not inject packets in Monitor mode

[dayrenefrometa]

Hi,

The issue is that Scapy does not inject packets in monitor mode. Sniffing works fine. The following are some packets captured in monitor mode:

This is my environment:

• WiFi chipset and driver: Atheros AR9285 and ath9k. The chipset supports monitor mode and packet injection. I have checked it with aireplay-ng.
• OS: Ubuntu 18.04 Desktop (kernel version: 5.4.0-89)
• Python version: 3.6.9
• Scapy version: 2.4.5

For installing Scapy I used:

• sudo python3 -m pip install --pre scapy[basic]

For setting the interface into Monitor mode:

airmon-ng check kill
airmon-ng start wlp2s0 9

(but I also tried with ifconfig and iwconfig)

My code for injecting packets with scapy is the following:

#!/usr/bin/python3

from scapy.all import *
conf.use_pcap = True
conf.iface = 'wlp2s0mon'

my_addr = '22:22:22:22:22:22'
dst_addr = 'ff:ff:ff:ff:ff:ff'

capture = sniff(count = 5,iface = conf.iface)
capture.summary()

beacon_pkt = RadioTap() / Dot11(addr1=dst_addr, addr2=my_addr, addr3=my_addr) \
             / Dot11Beacon() / Dot11Elt(ID='SSID', info='My_SSID', len=len('My_SSID'))

beacon_pkt.show()
print("\nHexdump of frame:")
hexdump(beacon_pkt)

input("\nPress enter to start\n")

sendp(beacon_pkt, inter=0.1, count=10, iface=conf.iface, monitor = True)

The injected packets look like this:

But the packet injection fails, reporting the following errors:

Traceback (most recent call last):
File "ScapyCodePython3.py", line 19, in
sendp(beacon_pkt, inter=0.1, count=10, iface=interface, monitor = True)
File "/usr/local/lib/python3.6/dist-packages/scapy/sendrecv.py", line 463, in sendp
**kargs
File "/usr/local/lib/python3.6/dist-packages/scapy/sendrecv.py", line 394, in _send
socket = socket or _func(iface)(iface=iface, **kargs)
File "/usr/local/lib/python3.6/dist-packages/scapy/arch/libpcap.py", line 407, in init
monitor=monitor)
File "/usr/local/lib/python3.6/dist-packages/scapy/arch/libpcap.py", line 247, in init
raise OSError("Could not activate the pcap handler")
OSError: Could not activate the pcap handler

I have already checked this issue #2076, and I tried to solve the problem by:

• Adding libpcap to my python environment sudo python3 -m pip install libpcap
• Installing both pcapy and pypcap
• Using the Master branch
• I saw they solved the problem using another version of the driver, so I installed a different version of the ath9k driver using backports. Specifically, I downloaded the stable backport backports-5.10.68-1.tar.gz and then used the following commands:

sudo make defconfig-ath9k
sudo make
sudo make install

But unfortunately, the problem persists.

Please, could anyone help me by suggesting something different to try? Is there anything wrong with the procedure/configuration that I described above?

Thank you very much in advance for your help.

Regards,

Dayrene

[gpotter2]

Hi,
I'll give some notes, but please note that this is not a forum but a bugtracker. This is probably more a question for stack overflow.

Did you check the documentation beforehand? https://scapy.readthedocs.io/en/latest/troubleshooting.html
Did you try without using libpcap, with monitor=False?

• Installing both pcapy and pypcap

This is pointless, we don't use those anymore.

• Adding libpcap to my python environment

The libpcap we use isn't a python package, and we aren't using those python bindings.

We don't really provide support regarding monitor mode, because the hardware requirements are very important and way out of the scope of this project. If libpcap does not succeed enabling monitor mode on a device, we won't do any better.