When a TSO user logs on, a Terminal Status Block (TSB) is created in fetch-protected storage to contain certain information about the session. Depending on logic in TSO's Logon Pre-Prompt exit, the cleartext RACF password might be stored in the TSB.

In our opinion, this increases opportunities for password compromise since authorized programs could collect them or because they might appear in certain system dumps.

If cleartext passwords appear in TSBs, PWCHECK notes this.