In general people (Technicians / Engineers / IT Responsibles) save all his passwords in Excel Files with passwords or with specific tools to save passwords like keepass etc...

In order to have a good CMDB it will be a good idea, store this passwords with the item Inventory. And only SDP technicians, and depending on what group they belong or not to see this password.

A good choice will be the possibility to add users and passwords for each access group.

example:

one Router

      User and password for Engineers web access (HIGH LEVEL ACCESS)

      User and password for Engineers telnet access(HIGH LEVEL ACCESS)

      User and password for Queries (SUPPORT)

      User and password for snmp read only (MONITORING)

      User and password for snmp write (MONITORING AND ENGINEERS)

It would be a possiblitity to add new fields with ****** and put a check box to see the content.

Sorry for my English