fragattacks/research

This repository contains scripts to test for Wi-Fi fragmentation and aggregation vulnerabilities.

Usage

Supported Network Cards

Only specific wireless network cards are supported. This is because some network cards may overwrite the sequence number of injected frames, may overwrite the fragment number, or reorder frames of different priority, and this interferes with our scripts (i.e. our script might incorrectly say a device is secure although it's not). We have confirmed that the following network cards work properly with our scripts:

Network Card	USB	injection mode	mixed mode	hwsim mode (experimental)
Intel AX200	No	?	?	?
Intel Wireless-AC 8265	No	yes	patched driver	as client
Intel Wireless-AC 3160	No	yes	patched driver/firmware	as client
Technoethical N150 HGA	Yes	patched driver/firmware	patched driver/firmware	patched driver/firmware
TP-Link TL-WN722N v1.x	Yes	patched driver/firmware	patched driver/firmware	patched driver/firmware
Alfa AWUS036NHA	Yes	patched driver/firmware	patched driver/firmware	patched driver/firmware
Alfa AWUS036ACM	Yes	?	?	?
Alfa AWUS036ACH	Yes	?	?	?
Netgear WN111v2	Yes	yes	patched driver	yes

The three last colums signify:

1. Injection mode: whether the network card can be used as a second interface to inject frames in [injection mode].

2. hwsim mode: whether the network card can be used in [hwsim mode].

3. Mixed mode: whether the network card can be used in [mixed mode].

We recommend the use of the Technoethical N150 HGA in either injection mode or mixed mode. It requires the use of a patched driver and firmware, but since it's a USB dongle this can be configured inside a virtual machine. If you are unable to find one of the above devices, you can search for [alternative devices] that have a high chance of also working.

Prerequisites

Our scripts were tested on Kali Linux and Ubuntu 20.04. To install the required dependencies, execute:

# Kali Linux and Ubuntu
apt-get update
apt-get install libnl-3-dev libnl-genl-3-dev libnl-route-3-dev libssl-dev libdbus-1-dev git pkg-config build-essential macchanger net-tools python3-venv

Now clone this repository, build the tools, and configure a virtual python3 environment:

git clone git@bitbucket.org:vanhoefm/fragattack-scripts.git --recursive
cd fragattack-scripts
./build.sh
cd research
python3 -m venv venv
source venv/bin/activate
pip install wheel
pip install -r requirements.txt

The above instructions only have to be executed once.

Patched Drivers

Install patched drivers:

apt-get install bison flex linux-headers-$(uname -r)
git clone git@bitbucket.org:vanhoefm/fragattack-backports57.git
cd fragattack-backports57.git
make defconfig-experiments
make -j 4
sudo make install

Install patched ath9k_htc firmware on Ubuntu:

cd research/ath9k-firmware/
cp htc_9271.fw /lib/firmware/ath9k_htc/htc_9271-1.4.0.fw
cp htc_7010.fw /lib/firmware/ath9k_htc/htc_7010-1.4.0.fw

TODO: How to install patched ath9k_htc drivers.

Before every usage

Every time you want to use the script, you first have to load the virtual python environment as root. This can be done using:

cd fragattack-scripts/research
sudo su
source venv/bin/activate

You should now disable Wi-Fi in your network manager so it will not interfere with our scripts.

Our script can test both clients and APs:

• Testing APs: configure the AP you want to test by editing research/client.conf. This is a standard wpa_supplicant configuration file, see the [hostap documentation] on how to edit it.

• Testing clients: you must execute the script with the extra --ap parameter. This instructs the script into creating an AP with as name testnetwork and password abcdefgh. Connect to this network with the client you want to test. By default the client must request an AP using DHCP. To edit properties of the created AP, such as the channel it's created on, you can edit research/hostapd.conf.

Testing Modes

Injection Mode

This mode requires two devices: one will act as an AP or the client, and the other will be used to inject frames. Execute the script in this mode using:

./fragattack wlan0 --inject wlan1 [--ap] $COMMAND

Here interface wlan0 will act as a legitimate client or AP, and wlan1 will be used to inject frames. For wlan0, any card that supports normal client or AP mode on Linux can be used. For wlan1, a card must be used that supports injection mode according to [Supported Network Cards].

In case the tests do not seem to be working, you can confirm that injection is properly working using:

./test-injection wlan1 wlan0

This will script will inject frames using interface wlan1, and uses wlan0 to check if frames are properly injected. Note that both interfaces need to support monitor mode for this script to work.

Mixed mode

This mode requires only one device. This disadvantage is that this mode requires a patched driver and/or firmware, and that only a small amount of devices are supported. Execute the script in this mode using:

./fragattack wlan0 [--ap] $COMMAND

Reference how to compile and install backport drivers.

Hwsim mode (experimental)

TODO: This mode isn't useful for Intel/mvm since it's too unreliable... Bootable Live CD is better!

This mode requires only one device. The disadvantage is that this mode is the least reliable:

• Frames are handled slower, possibly causing the tested client/AP to timeout during authentication or association.

• When injeting frames, they may be retransmitted even though an acknowledgement was recieved. This will further slightly slowdown the handling of frames.

• Frames are not properly acknowledged depending on the wireless network card, which causes some tested clients or APs to disconnect during authentication or association.

Nevertheless, the advantage is that is mode can, depending on the network card, be used without patches to the driver and/or firmware. Before using this mode, create two virtual network cards:

./hwsim.sh

This will output the two created virtual "hwsim" interfaces, for example wlan1 and wlan2. Then search for the channel of the AP you want to test, and put the real network card on this channel: TODO: recommend channel 1-13? TODO: do we also support AP mode? I suppose for patched ath9k_htc it does work.

./scan.sh wlan0
iw wlan0 set type monitor
ifconfig wlan0 up
iw wlan0 set channel 11
**TODO: sudo iw wlan0 set monitor otherbss. Does airmon-ng handle this better? Move to general section?**

You can now start the script as follows:

./fragattack wlan0 --hwsim wlan1,wlan2 [--ap] $COMMAND

After the script executed, you can directly run it again with a new command.

Testing for Vulnerabilities

We recommend executing the following tests. The tests marked in bold correspond to vulnerabilities, and the other tests are useful to understand the behaviour of the device under test.

Test	Command	Short description
Normal ping	ping I,E	Send a normal ping
Fragmented ping	ping I,E,E	Send a fragmented ping
Fragmentation timeout	ping I,E,E --delay 5	Send a fragmented ping with a 5s delay between fragments
Non-consecutive	ping I,E,E --inc-pn 2	Send a fragmented ping with non-consecutive packet numbers.
Seperator	ping-frag-sep	Send a fragmented ping with fragments separated by a normal frame
Mixed key	ping I,R,BE,AE	As client wait for rekey and as AP force rekey, then encrypt fragments under different keys.
	ping I,R,BE,AE --pn-per-qos	Same as above, except it also work when the device doesn't accept non-consecutive fragments.
Cache Poison	ping I,E,C,AE	Inject a fragment, as client reassociate and as AP force tested client to reconnect, then inject second fragment.
	ping I,E,C,E	Same as above, except there is a longer delay before sending the second fragment.
	ping I,E,C,AE --full-reconnect	Inject a fragment, as client reconnect and as AP force tested client to reconnect, then inject second fragment.
	ping I,E,C,E --full-reconnect	Same as above, except there is a longer delay before sending the second fragment.
A-MSDU	ping I,E --amsdu	Send a normal ping encapsulated in a normal A-MSDU frame.
	ping I,E,E --amsdu	Send a normal ping an a fragmented A-MSDU frame.
	amsdu-inject	Send a valid A-MSDU frame whose start is also a valid LLC/SNAP header.
	amsdu-inject linux	Send an invalid A-MSDU frame whose start is also a valid LLC/SNAP header (frame treated as valid by Linux/FreeBSD).
Mixed Plain/Enc	ping I,E,P	Send a fragmented ping: first fragment encrypted, second fragment in plaintext.
	ping I,P,E	Send a fragmented ping: first fragment in plaintext, send fragment encrypted.
	ping I,P	Send a plaintext ping.
	ping I,P,P	Send a fragmented ping: both fragments are sent in plaintext.
Linux Plain/Enc	linux-plain	Mixed plaintext/encrypted fragmentation attack specific to Linux.
EAPOL A-MSDU	eapol-amsdu BB	Send A-MSDU frame disguised as EAPOL frame. Run tcpdump on target to check if vulnerable.
	eapol-amsdu I,CC	Same as above, except the frame is injected after being connected and obtaining an IP.
	eapol-amsdu M,BB	Send a malformed A-MSDU frame disguised as EAPOL frame. Use tcpdump to check if vulnerable.
	eapol-amsdu M,I,CC	Same as above, except the frame is injected after being connected and obtaining an IP.
MacOS Plain Inject	macos BB	Fragmented EAPOL attack (notably works against MacOS). Run tcpdump on target to check if vulnerable.
Broadcast ping	ping I,D,P --bcast-ra	Send ping inside the second plaintext fragment of a broadcast Wi-Fi frame (no 1st fragment is sent).

Optionally you can also run more advanced tests. These have a lower chance of uncovering vulnerabilities, but against more exotic implementations that might work (while the above tests could fail).

Test	Command	Short description
Mixed key	ping I,E,R,AE	Inspired by MediaTek case
	ping I,E,R,AE --rekey-plaintext	Mixed key attack against MediaTek
	ping I,E,R,AE --rekey-request --rekey-plaintext	Mixed key attack against MediaTek
	ping I,E,R,AE --rekey-early-install	TODO
	ping I,R,BE,AE --freebsd	Mixed key attack against FreeBSD
	ping I,R,BE,E	If the new key is installed late (observed with AWUS036ACH on Kali). Other variants?
Mixed Plain/Enc	ping I,E,P,E	Send a fragmented ping: first fragment encrypted, second plaintext, third encrypted.
	linux-plain 3	Mixed plaintext/encrypted fragmentation attack, decoy fragment is sent using QoS TID 3.
EAPOL A-MSDU	eapol-amsdu [M,]BB --bcast-dst	Same as "eapol-amsdu [M,]BB" but ping is broadcasted. To test AP, check if a 2nd client receives the ping.
	eapol-amsdu [M,]I,CC --bcast-dst	Same as "eapol-amsdu [M,]I,CC" but ping is broadcasted. To test AP, check if a 2nd client receives the ping.
	eapol-amsdu SS
	eapol-amsdu AA
MacOS Plain Inject	macos CC	Fragmented EAPOL attack (notably works against MacOS). Run tcpdump on target to check if vulnerable.
Broadcast ping	ping I,P,P --bcast-ra	Send ping inside two plaintext fragments of a broadcast Wi-Fi frame.
	ping I,P --bcast-ra	Send ping inside a plaintext broadcast Wi-Fi frame.

Details remarks:

• Fragmentation timeout: this test is used to check the maximum accepted delay between two fragments. If the default test doesn't work, try with --delay 2 or lower. In case the maximum accepted delay is low, this may impact other tests. All fragments sent in other tests must be sent within the maximum delay, otherwise the test will automatically fail (and you might conclude a device isn't. vulnerable to an attack even though it might be.

• When running the mixed key test against an AP, the AP must be configured to regularly renew the PTK by executing a new 4-way handshake (e.g. every 30 seconds or minute). Against a low number of APs, the client can also request the AP to renew the PTK. This can be done by adding the --rekey-request parameter.

  Home routers with a MediaTek driver will perform the rekey handshake in plaintext. To test these devices, also add the --rekey-plaintext parameter.

  Against unknown devices, the PTK will be installed too early. To test these devices, add the --rekey-early-install parameter and retry the test.

In case you are testing a device which should be vulnerable, but the script doesn't detect that it's vulnerable, double check the following things:

1. Check that you are using modified drivers if needed for your wireless network card.

2. Check that you are using modified firmware if needed for your wireless network card.

3. Run the [device injection tests] to make sure injection is working properly.

4. Check that he machine that executes the script doesn't generate background traffic that might interfere with the tests. In particular, remember to disable network in your OS, manually kill your DHCP client/server, etc.

5. Confirm that you are connecting to the correct network. Double-check client.conf.

6. Make sure the network is using (AES-)CCMP as the encryption algorithm.

Advanced Usage

Static IP Configuration

In case the device you are testing doesn't support DHCP, you can manually specify the IP addresses that the script should use. For example:

./fragattack.py wlan0 ping --inject wlan1 --ip 192.168.100.10 --peerip 192.168.100.1

Here the testing script will use address 192.168.100.10, and it will inject a ping request to the peer IP address 192.168.100.1.

TODOs

• Confirm each device can detect all vulnerabilities in the recommended modes.

• Test the attacks against PEAP-MSchap for eduroam tests (basic test was working).

• TODO: Is it important to disable encryption? I don't think it is. Otherwise we need sysfsutils as a dependency too.

• Include references to sections in the paper for the command overview table.

• Create an example pcap and debug output of all tests.

• Release a known vulnerable linux image to test against? Essential to confirm the tests are working!

Live CD

• Boot Ubuntu with exactly the same kernel as the live CD
• Install the scripts
• Buil the backport drivers
• Run depmod manually
• Continue