airbase-ng - multi-purpose tool aimed at attacking clients as opposed to the
Access Point (AP) itself
[options] <interface name>
is multi-purpose tool aimed at attacking clients as opposed to
the Access Point (AP) itself. Since it is so versatile and flexible,
summarizing it is a challenge. Here are some of the feature highlights:
- Implements the Caffe Latte WEP client attack
- Implements the Hirte WEP client attack
- Ability to cause the WPA/WPA2 handshake to be captured
- Ability to act as an ad-hoc Access Point
- Ability to act as a full Access Point
- Ability to filter by SSID or client MAC addresses
- Ability to manipulate and resend packets
- Ability to encrypt sent packets and decrypt received packets
The main idea is of the implementation is that it should encourage clients to
associate with the fake AP, not prevent them from accessing the real AP.
A tap interface (atX) is created when airbase-ng is run. This can be used to
receive decrypted packets or to send encrypted packets.
As real clients will most probably send probe requests for common/configured
networks, these frames are important for binding a client to our softAP. In
this case, the AP will respond to any probe request with a proper probe
response, which tells the client to authenticate to the airbase-ng BSSID. That
being said, this mode could possibly disrupt the correct functionality of many
APs on the same channel.
- -H, --help
- Shows the help screen.
- -a <bssid>
- If the BSSID is not explicitly specified by using "-a
<BSSID>", then the current MAC of the specified interface is
- -i <iface>
- Also capture and process from this interface in addition to
the replay interface.
- -w <WEP key>
- If WEP should be used as encryption, then the parameter
"-w <WEP key>" sets the en-/decryption key. This is
sufficient to let airbase-ng set all the appropriate flags by itself. If
the softAP operates with WEP encryption, the client can choose to use open
system authentication or shared key authentication. Both authentication
methods are supported by airbase-ng. But to get a keystream, the user can
try to force the client to use shared key authentication. "-s"
forces a shared key auth and "-S <len>" sets the challenge
- -h <MAC>
- This is the source MAC for the man-in-the-middle attack.
The "-M" must also be specified.
- -f <disallow>
- If this option is not specified, it defaults to "-f
allow". This means the various client MAC filters (-d and -D) define
which clients to accept.
By using the "-f disallow" option, this reverses selection and
causes airbase to ignore the clients specified by the filters.
- -W <0|1>
- This sets the beacon WEP flag. Remember that clients will
normally only connect to APs which are the same as themselves. Meaning WEP
to WEP, open to open.
The "auto" option is to allow airbase-ng to automatically set the
flag based on context of the other options specified. For example, if you
set a WEP key with -w, then the beacon flag would be set to WEP.
One other use of "auto" is to deal with clients which can
automatically adjust their connection type. However, these are few and far
In practice, it is best to set the value to the type of clients you are
- This suppresses printing any statistics or status
- This prints additional messages and details to assist in
- This option is not implemented yet. It is a
man-in-the-middle attack between specified clients and BSSIDs.
- -A, --ad-hoc
- This causes airbase-ng to act as an ad-hoc client instead
of a normal Access Point.
In ad-hoc mode airbase-ng also sends beacons, but doesn't need any
authentication/association. It can be activated by using "-A".
The soft AP will adjust all flags needed to simulate a station in ad-hoc
mode automatically and generate a random MAC, which is used as CELL MAC
instead of the BSSID. This can be overwritten by the "-a
<BSSID>" tag. The interface MAC will then be used as source
mac, which can be changed with "-h <sourceMAC>".
- -Y <in|out|both>
- The parameter "-Y" enables the "external
processing" Mode. This creates a second interface "atX",
which is used to replay/modify/drop or inject packets at will. This
interface must also be brought up with ifconfig and an external tool is
needed to create a loop on that interface.
The packet structure is rather simple: the ethernet header (14 bytes) is
ignored and right after that follows the complete ieee80211 frame the same
way it is going to be processed by airbase-ng (for incoming packets) or
before the packets will be sent out of the wireless card (outgoing
packets). This mode intercepts all data packets and loops them through an
external application, which decides what happens with them. The MAC and IP
of the second tap interface doesn't matter, as real ethernet frames on
this interface are dropped dropped anyway.
There are 3 arguments for "-Y": "in", "out"
and "both", which specify the direction of frames to loop
through the external application. Obviously "in" redirects only
incoming (through the wireless NIC) frames, while outgoing frames aren't
touched. "out" does the opposite, it only loops outgoing packets
and "both" sends all both directions through the second tap
There is a small and simple example application to replay all frames on the
second interface. The tool is called "replay.py" and is located
in "./test". It's written in python, but the language doesn't
matter. It uses pcapy to read the frames and scapy to possibly alter/show
and reinject the frames. The tool as it is, simply replays all frames and
prints a short summary of the received frames. The variable
"packet" contains the complete ieee80211 packet, which can
easily be dissected and modified using scapy.
This can be compared to ettercap filters, but is more powerful, as a real
programming language can be used to build complex logic for filtering and
packet customization. The downside on using python is, that it adds a
delay of around 100ms and the cpu utilizations is rather large on a high
speed network, but its perfect for a demonstration with only a few lines
- -c <channel>
- This is used to specify the channel on which to run the
- -X, --hidden
- This causes the Access Point to hide the SSID and to not
broadcast the value.
- When specfiied, this forces shared key authentication for
The soft AP will send an "authentication method unsupported"
rejection to any open system authentication request if "-s" is
- It sets the shared key challenge length, which can be
anything from 16 to 1480. The default is 128 bytes. It is the number of
bytes used in the random challenge. Since one tag can contain a maximum
size of 255 bytes, any value above 255 creates several challenge tags
until all specified bytes are written. Many clients ignore values
different than 128 bytes so this option may not always work.
- -L, --caffe-latte
- Airbase-ng also contains the new caffe-latte attack, which
is also implemented in aireplay-ng as attack "-6". It can be
used with "-L" or "caffe-latte". This attack
specifically works against clients, as it waits for a broadcast arp
request, which happens to be a gratuitous arp. See this for an
explaination of what a gratuitous arp is. It then flips a few bits in the
sender MAC and IP, corrects the ICV (crc32) value and sends it back to the
client, where it came from. The point why this attack works in practice
is, that at least windows sends gratuitous arps after a connection on
layer 2 is established and a static ip is set, or dhcp fails and windows
assigned an IP out of 169.254.X.X.
"-x <pps>" sets the number of packets per second to send
when performing the caffe-latte attack. At the moment, this attack doesn't
stop, it continuously sends arp requests. Airodump-ng is needed to capture
- -N, --cfrag
- This attack listens for an ARP request or IP packet from
the client. Once one is received, a small amount of PRGA is extracted and
then used to create an ARP request packet targeted to the client. This ARP
request is actually made of up of multiple packet fragments such that when
received, the client will respond.
This attack works especially well against ad-hoc networks. As well it can be
used against softAP clients and normal AP clients.
- -x <nbpps>
- This sets the number of packets per second that packets
will be sent (default: 100).
- When using this option, the fake AP will not respond to
broadcast probes. A broadcast probe is where the the specific AP is not
identified uniquely. Typically, most APs will respond with probe responses
to a broadcast probe. This flag will prevent this happening. It will only
respond when the specific AP is uniquely requested.
- This enables all WPA/WPA2/WEP Tags to be enabled in the
beacons sent. It cannot be specified when also using -z or -Z.
- -z <type>
- This specifies the WPA beacon tags. The valid values are:
1=WEP40 2=TKIP 3=WRAP 4=CCMP 5=WEP104.
- -Z <type>
- same as -z, but for WPA2
- -V <type>
- This specifies the valid EAPOL types. The valid values are:
1=MD5 2=SHA1 3=auto
- -F <prefix>
- This option causes airbase-ng to write all sent and
received packets to a pcap file on disk. This is the file prefix (like
- This causes the fake access point to respond to all probes
regardless of the ESSIDs specified.
- -I <interval>
- This sets the time in milliseconds between each
- -C <seconds>
- The wildcard ESSIDs will also be beaconed this number of
seconds. A good typical value to use is "-C 60" (require
- -n <hex>
- ANonce (nonce from the AP) to use instead of a randomized
one. It must be 64 hexadecimal characters.
- Filter options:
- --bssid <MAC>, -b <MAC>
- BSSID to filter/use.
- --bssids <file>, -B <file>
- Read a list of BSSIDs out of that file.
- --client <MAC>, -d <MAC>
- MAC of client to accept.
- --clients <file>, -D <file>
- Read a list of client's MACs out of that file
- --essid <ESSID>, -e <ESSID>
- Specify a single ESSID. For SSID containing special
- --essids <file>, -E <file>
- Read a list of ESSIDs out of that file. It will use the
same BSSID for all AP which can generate some interesting output in
This manual page was written by Thomas d'Otreppe. Permission is granted to copy,
distribute and/or modify this document under the terms of the GNU General
Public License, Version 2 or any later version published by the Free Software
Foundation On Debian systems, the complete text of the GNU General Public
License can be found in /usr/share/common-licenses/GPL.