Use PRODUCT_USER_PROFILE To Limit User

The PRODUCT_USER_PROFILE (PUP) table provides product-level security that supplements the user-level security provided by the SQL GRANT and REVOKE commands and user roles. To create the PUP table, log in to SQL*Plus as the SYSTEM user and run PUPBLD.SQL which is located in the ORACLE_HOMESQLPLUSADMIN directory with:

[oracle@nbuserver admin]$ ls
glogin.sql help libsqlplus.def plustrce.sql pupbld.sql
[oracle@nbuserver admin]$
[oracle@nbuserver admin]$
[oracle@nbuserver admin]$
[oracle@nbuserver admin]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Sun Aug 24 07:20:41 2014

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 – 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SYS@orcl11g>@pupbld.sql

insert into product_user_profile values('SQL*Plus','SCOTT','DROP',null,null,'DISABLED',null,null);

reconnect sql*plus:

conn scott/tiger;

Connected.
SYS@orcl11g>conn scott/tiger;
Connected.
SCOTT@orcl11g>drop table zbdba;
SP2-0544: Command "drop" disabled in Product User Profile

for more information:

http://docs.oracle.com/cd/A64702_01/doc/server.805/a53717/ape.htm