You can’t make a password strong enough. But at least you can try. Having at least one upper case character, one lower case character, one number, one punctuation mark or symbol, and greater than 8 characters, you can have a password which can be considered something decently safe, probably.
In Oracle, if you embed punctuation marks within your passwords, you have to use single quote around that password if you are using orapwd utility from command line. If you are altering the password from the sqlplus utility, you need to use the double quotes around the password.
Example of both is given below, as sys password is being changed:
$ORACLE_HOME/dbs $ orapwd file=orapwtest password=”My1s!pass” entries=40 force=y
-bash: !pass”: event not found
$ORACLE_HOME/dbs $ orapwd file=orapwtest password=’My1s!pass’ entries=40 force=y
SQL> alter user sys identified by ‘My1s!pass’;
alter user sys identified by ‘My1s!pass
ERROR at line 1:
ORA-00988: missing or invalid password(s)
SQL> alter user sys identified by “My1s!pass”;