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I am trying to set my wireless card into monitor mode. I am working with:

description: Wireless interface
product: BCM4312 802.11b/g LP-PHY
vendor: Broadcom Corporation
logical name: eth2

When I try to set it to monitor mode I get:

sudo iwconfig eth2 mode monitor
Error for wireless request "Set Mode" (8B06) :
    SET failed on device eth2 ; Invalid argument.

I also tried using:

$ sudo airmon-ng start eth2


Found 5 processes that could cause trouble.
If airodump-ng, aireplay-ng or airtun-ng stops working after
a short period of time, you may want to kill (some of) them!

PID    Name
1094    NetworkManager
1096    avahi-daemon
1097    avahi-daemon
1167    wpa_supplicant
1720    dhclient
Process with PID 1720 (dhclient) is running on interface eth2


Interface    Chipset        Driver

eth2        Unknown         wl (monitor mode enabled)

$ sudo iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

eth2      IEEE 802.11bg  ESSID:"Redacted"  
          Mode:Managed  Frequency:2.437 GHz  
          Bit Rate=54 Mb/s   Tx-Power:24 dBm  
          Retry min limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=4/5  Signal level=-59 dBm  Noise level=-57 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:24  Invalid misc:0   Missed beacon:0

I've gone through various driver tutorials, but nothing is helping. Anyone know how to get this working for this specific wireless card?

ish
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tylerthemiler
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3 Answers3

9

The official Broadcom STA/wl driver DOES NOT support monitor mode

  • You are using the Broadcom STA (wl) official driver; this does not support monitor or promiscuous modes (regardless of whatever airmon-ng tells you.)
  • For this you need the b43 driver, which can be installed with sudo apt-get install b43-fwcutter firmware-b43-installer
  • You can unload one and load the other with sudo rmmod wl; sudo modprobe b43 (and vice versa).
  • Note that b43 and wl have their own advantages and disadvantages, so you may want to google before choosing one or the other.
Community
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ish
  • 139,926
  • Hey izx. I got installed b43-fwcutter, firmware-b43-installer. Then I tried sudo apt-get install b43-fwcutter firmware-b43-installer this stops my wireless card and iwconfig give no results. My wireless card is: Broadcom Corporation Device [14e4:4365] Could you pls help me – codeomnitrix Mar 23 '13 at 15:45
  • The official Broadcom STA/wl driver DOES support monitor mode. See my answer below. – ssice Mar 26 '13 at 16:52
  • @codeomnitrix sudo echo 1 > /proc/brcm_monitor0 enables monitor mode for wl. A new device name prism0 will appear, that's your monitor. Unfortunately, I seem to be having trouble deauthing - everything else works just fine. – Powerslave Dec 04 '17 at 01:38
  • FYI I had to restart after loading and unloading a module for the new one to work – Escobar5 Apr 29 '20 at 19:45
8

The above answer is not true. At least, from version 5.100.82.1 (I think that is from year 2007 or so).

The official Broadcom STA/wl driver does support monitor mode

However, it's not standard the way it does, so in order to enable it you have to do the following:

  • You have to type in a 1 to the file /proc/brcm_monitor0. You may do this via the following shell command: echo 1 | sudo tee /proc/brcm_monitor0.
  • It will create a new interface. The interface is called prism0, and not mon0.

Enjoy.

In my case, I can't set b43 up, and whenever I actually get the kernel to load it, my connectivity will drop to unusable, dropping most packets.

I hate wl not being free, but I can't use the b43 alternative in my BCM4322.

ssice
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  • hey ssice, i tried to change file to contain 1 but I am still not getting any new interface as you mentioned. could you pls help me. my wireless card is Broadcom Corporation Device [14e4:4365] – codeomnitrix Mar 23 '13 at 15:50
  • Might it be related to http://superuser.com/questions/454784/dell-inspiron-5420-wifi-drivers-pci-id-14e44365 ? It seems to me that your card does not have as good support. Doesn't the new interface show up in programs like wireshark? – ssice Mar 23 '13 at 18:21
  • Hey although it don't show up but still I am able to use airodump on this interface. thanks. But one strange thing happening all the time I turn on monitor mode from /proc/brcm_monitor0 when i got to turn that off, it just crashes the system and some dump screen comes. – codeomnitrix Mar 24 '13 at 17:08
  • I don't know. In my config it doesn't, but if you are using the driver that is in my link above (there's the link to the README), I don't see your card in the list of supported devices. Maybe that particular opcode for turning off the monitor mode is not well handled. – ssice Mar 25 '13 at 15:51
  • Ya it is not listed over there, could you please help me how to turn off monitor mode my card is: 14e4:4365 Thanks – codeomnitrix Mar 26 '13 at 04:27
  • Hey wait I am using the modified wl driver from this question http://askubuntu.com/questions/175104/how-do-i-install-bcm43142-wireless-drivers-for-dell-vostro-3460-3560 – codeomnitrix Mar 26 '13 at 05:18
  • You might want to report it as a bug in LaunchPad. I am using 'vanilla' wl driver, and it works fine with the supported models. Maybe it's a bug from Dell. However, if you can put the card in monitor mode, it's pretty much harmless not to put it back off (you can always restart if you really need to. Hope I helped. At least you get monitor mode! :) – ssice Mar 26 '13 at 16:52
  • Even after creating the prism0 interface, injection with aireplay is not working and neither is reaver. My card is a :43a0 which is unsupported by the b43 driver. – Henrique de Sousa Jan 27 '15 at 00:32
  • Your 14e4:43a0 may not support packet injection. This seems to be consistent with other experiments, see http://saltwaterc.github.io/aircrack-db/ – ssice Jan 27 '15 at 11:53
1

If you choose to use non official drivers, pay attention that it doesn't support all cards. Check it here: http://wireless.kernel.org/en/users/Drivers/b43#Supported_devices

For example (not supported): Broadcom Corporation Device [14e4:4365]

Check your card:

lspci -vnn -d 14e4:
linuxMint
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