Information
ExtProc functionality allows external C and Java functions to be called from within PL/SQL. If extproc functionality is not required,
remove this entry. If extproc functionality is required, refer to Oracle Metalink Security Alert 57 (244523.1) for instructions on
securing extproc. In short, create a new listener specifically for extproc. This listener must run as an unprivileged OS user.
Solution
Remove extproc from the listener.ora.