Below steps for changing the mdbadmin password for catalog:
1. Login to Catalog Server
2. Take a backup of config.properties file under "USM_HOME"
Note: USM_HOME is the installaiton directory of Catalog
3. Open a command prompt and change the dorectory to USM_HOME/scripts
4. You will find encrypter.bat file. Run the below command to encrypt your password
encrypter.bat <YOur Password>
5. You will be present with the exncrypted password
6. Copy the password and update the config.properties file under USM_HOME directory for the following parameters
DBSource.password = <Paste the new encrypted Password here>
7. Recycle the Catalog Services