Aircrack-ng is a Wi-Fi security auditing tool specifically 802.11 WEP and WPA/WPA2-PSK. Aircrack-ng is used by security professionals to test the reliability of wireless networks. This program is covered in the Wireless Attacks (PEN-210) (WiFu) course from Offensive Security and many other information security courses.
This is a program for professionals in the field of IT security, its use requires the consent of the owner of the wireless network.
Using this program without the knowledge of the Wi-Fi owner is a legal violation.
Aircrack-ng can recover the WEP key once enough encrypted packets have been captured with airodump-ng. This part of the aircrack-ng suite determines the WEP key using two fundamental methods. The first method is via the PTW approach (Pyshkin, Tews, Weinmann). The default cracking method is PTW. This is done in two phases. In the first phase, aircrack-ng only uses ARP packets. If the key is not found, then it uses all the packets in the capture. Please remember that not all packets can be used for the PTW method. This Tutorial: Packets Supported for the PTW Attack page provides details. An important limitation is that the PTW attack currently can only crack 40 and 104 bit WEP keys. The main advantage of the PTW approach is that very few data packets are required to crack the WEP key. The second method is the FMS/KoreK method. The FMS/KoreK method incorporates various statistical attacks to discover the WEP key and uses these in combination with brute forcing.
Additionally, the program offers a dictionary method for determining the WEP key.
For cracking WPA/WPA2 pre-shared keys, only a dictionary method is used. SSE2 support is included to dramatically speed up WPA/WPA2 key processing. A “four-way handshake” is required as input. For WPA handshakes, a full handshake is composed of four packets. However, aircrack-ng is able to work successfully with just 2 packets. EAPOL packets (2 and 3) or packets (3 and 4) are considered a full handshake.
Author: Thomas d’Otreppe
usage: aircrack-ng [options] <input file(s)> Common options: -a <amode> : force attack mode (1/WEP, 2/WPA-PSK) -e <essid> : target selection: network identifier -b <bssid> : target selection: access point's MAC -p <nbcpu> : # of CPU to use (default: all CPUs) -q : enable quiet mode (no status output) -C <macs> : merge the given APs to a virtual one -l <file> : write key to file. Overwrites file. Static WEP cracking options: -c : search alpha-numeric characters only -t : search binary coded decimal chr only -h : search the numeric key for Fritz!BOX -d <mask> : use masking of the key (A1:XX:CF:YY) -m <maddr> : MAC address to filter usable packets -n <nbits> : WEP key length : 64/128/152/256/512 -i <index> : WEP key index (1 to 4), default: any -f <fudge> : bruteforce fudge factor, default: 2 -k <korek> : disable one attack method (1 to 17) -x or -x0 : disable bruteforce for last keybytes -x1 : last keybyte bruteforcing (default) -x2 : enable last 2 keybytes bruteforcing -X : disable bruteforce multithreading -y : experimental single bruteforce mode -K : use only old KoreK attacks (pre-PTW) -s : show the key in ASCII while cracking -M <num> : specify maximum number of IVs to use -D : WEP decloak, skips broken keystreams -P <num> : PTW debug: 1: disable Klein, 2: PTW -1 : run only 1 try to crack key with PTW -V : run in visual inspection mode WEP and WPA-PSK cracking options: -w <words> : path to wordlist(s) filename(s) -N <file> : path to new session filename -R <file> : path to existing session filename WPA-PSK options: -E <file> : create EWSA Project file v3 -j <file> : create Hashcat v3.6+ file (HCCAPX) -J <file> : create Hashcat file (HCCAP) -S : WPA cracking speed test -Z <sec> : WPA cracking speed test length of execution. -r <DB> : path to airolib-ng database (Cannot be used with -w) SIMD selection: --simd-list : Show a list of the available SIMD architectures, for this machine. --simd=<option> : Use specific SIMD architecture. <option> may be one of the following, depending on your platform: generic avx512 avx2 avx sse2 altivec power8 asimd neon Other options: -u : Displays # of CPUs & MMX/SSE support --help : Displays this usage screen
Aircrack-ng Usage Example
Using the provided wordlist (-w /usr/share/wordlists/nmap.lst), attempt to crack passwords in the capture file (capture-01.cap):
root@kali:~# aircrack-ng -w /usr/share/wordlists/nmap.lst capture-01.cap Opening capture-01.cap Read 2 packets. # BSSID ESSID Encryption 1 38:60:77:23:B1:CB 6EA10E No data - WEP or WPA Choosing first network as target. Opening capture-01.cap
How to install Aircrack-ng
The program is pre-installed on Kali Linux.
Installation on Linux (Debian, Mint, Ubuntu)
sudo apt-get install aircrack-ng
- 1 = Keybyte
- 2 = Depth of current key search
- 3 = Byte the IVs leaked
- 4 = Votes indicating this is correct
- Hacking WPA/WPA2 passwords with Aircrack-ng: dictionary attack, cooperation with Hashcat, maskprocessor, statsprocessor, John the Ripper, Crunch, hacking in Windows
- Hacking Wi-Fi without users in Aircrack-ng
- Main documentation: Aircrack-ng
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