• Sends a normal HTTP request and analyses the response; this identifies a number of WAF solutions
• If that is not successful, it sends a number of (potentially malicious) HTTP requests and uses simple logic to deduce which WAF it is
• If that is also not successful, it analyses the responses previously returned and uses another simple algorithm to guess if a WAF or security solution is actively responding to our attacks

What does it detect?
It detects a number of WAFs. To view which WAFs it is able to detect run WAFW00F with the -l option. At the time of writing the output is as follows:

$ ./wafw00f -l

                                 ^     ^
        _   __  _   ____ _   __  _    _   ____
       ///7/ /.' \ / __////7/ /,' \ ,' \ / __/
      | V V // o // _/ | V V // 0 // 0 // _/
      |_n_,'/_n_//_/   |_n_,' \_,' \_,'/_/
                                <
                                 ...'

    WAFW00F - Web Application Firewall Detection Tool

    By Sandro Gauci && Wendel G. Henrique

Can test for these WAFs:

Anquanbao
Juniper WebApp Secure
IBM Web Application Security
Cisco ACE XML Gateway
F5 BIG-IP APM
360WangZhanBao
ModSecurity (OWASP CRS)
PowerCDN
Safedog
F5 FirePass
DenyALL WAF
Trustwave ModSecurity
CloudFlare
Imperva SecureSphere
Incapsula WAF
Citrix NetScaler
F5 BIG-IP LTM
Art of Defence HyperGuard
Aqtronix WebKnight
Teros WAF
eEye Digital Security SecureIIS
BinarySec
IBM DataPower
Microsoft ISA Server
NetContinuum
NSFocus
ChinaCache-CDN
West263CDN
InfoGuard Airlock
Barracuda Application Firewall
F5 BIG-IP ASM
Profense
Mission Control Application Shield
Microsoft URLScan
Applicure dotDefender
USP Secure Entry Server
F5 Trafficshield

How do I use it?
For help please make use of the --help option. The basic usage is to pass it a URL as an argument. Example:

$./wafw00f https://www.ibm.com/

                                 ^     ^
        _   __  _   ____ _   __  _    _   ____
       ///7/ /.' \ / __////7/ /,' \ ,' \ / __/
      | V V // o // _/ | V V // 0 // 0 // _/
      |_n_,'/_n_//_/   |_n_,' \_,' \_,'/_/
                                <
                                 ...'

    WAFW00F - Web Application Firewall Detection Tool

    By Sandro Gauci && Wendel G. Henrique

Checking https://www.ibm.com/
The site https://www.ibm.com/ is behind a Citrix NetScaler
Number of requests: 6

How do I install it?
The following should do the trick:

python setup.py install

or

pip install wafw00f