Why does Scheduled job in Dispatcher fails with Oracle error ORA-27369

From Oracle versions 10.2.0.2 and higher,  external job scheduling system from the database will read externaljob.ora file in path $ORACLE_HOME/rdbms/admin.

External jobs not in SYS schema and with no credential run as the user and group specified in externaljob.ora file.The default is nobody. External jobs in SYS schema without credentials are run as the oracle user.
Oracle versions lower than 10.2.0.2 does not have externaljob.ora  and hence above settings are not applicable.

The following is the solution to resolve the issue with running scheduled jobs without Oracle error ORA-27369

Oracle version 10.2.0.2 and higher:

• rdbms/admin/externaljob.ora file must be owned by root:oraclegroup and be writable only by the owner i.e. 644 (rw-r--r--). File must contain at least two lines: one specifying the run-user and one specifying the run-group.
• bin/extjob file must be owned by root:oraclegroup but must be setuid i.e. 4750 (-rwsr-x---)
• bin/extjobo should have normal 755 (rwxr-xr-x) permissions and be owned by oracle:oraclegroup

Oracle version 11g and higher:

Same as 10.2.0.2 but additionally bin/jssu should exist with root setuid permissions i.e. owned by root:oraclegroup with 4750 (-rwsr-x---)
 

ORA-27369: job of type EXECUTABLE failed with exit code: 274662 Oracle Scheduler error: Config file is not owned by root or is writable 
STANDARD_ERROR="Oracle Scheduler error: Config file is not owned by root or is writable by group or other or extjob is not setuid and owned by root"

Scheduled jobs fails with Oracle error ORA-27369 due to grant permissions for root user against files external job scheduling system would read

The external jobs scheduled from within the database will run by the settings defined in the externaljob.ora file. The externaljob.ora has run_user=nobody and run_owner=nobody by default.