It’s bit old tip. But if you still run Exchange Server 2003, you can use this to tweak your security settings very easily. By default the security tab is disabled for most objects, e.g., Organization. The following steps to add a registry entry to enable the security tab for the Exchange System Manager.
1. Run Regedit then navigate to the HKCU (not the HKLM): HKEY_Current_UserSoftwareMicrosoftExchangeExAdmin.
2. Once you reach the above folder in the registry, select New, REG_DWORD called ShowSecurityPage.
3 . Set the value to 1 (one) for the ShowSecurityPage entry.
4: Re-open the Exchange System Manager and notice the new Security tab.
Anand, the Architect 