You can secure the userid and password in the following ways if you do not use trusted transfer option in XCOM:
1. Remove Parameters USERID= and PASSWORD= fron the SYSIN01 and store it in a separate member.
Then concatenate that member behind DD-Card SYSIN01 as follows
//SYSIN01 DD *
// DD DISP=SHR,DSN=DDD.EEE.FFF(USERPASS)
2. You can encrypt the password in that member by using the XCOMENCR job provided in the CBXGLOAD dataset.
This will replace the readeable password by an encrypted one. XCOM is able to interprete that encrypted password.
3. You can restrict access to the dataset (in this example 'DDD.EEE.FFF') to a small number of users.