One of the things that gets unnoticed or (overlooked) when securing Oracle Database Infrastructure is securing oracle database binaries by updating JDK build or updating SQL Developer.

When installing Oracle database binaries the version in a database install is always going to be behind the latest JDK so you should update to the latest version since latest version will include security fixes.

to check your current JDK build:

cd $ORACLE_HOME/jdk/bin

java –version

Procedure to replace JDK:

shutdown your oracle database and listener.

cd $ORACLE_HOME

mv jdk jdk.orig

//  you can download the Latest Java SE Patches/Update Releases on MOS (Doc ID 1414485.1) OR All Java SE Downloads on MOS (Doc ID 1439822.1)

//  copy the downloaded JDK to $ORACLE_HOME

scp jdk-6u181-linux-x64.bin $ORACLE_HOME

cd $ORACLE_HOME

./jdk-6u181-linux-x64.bin

cd $ORACLE_HOME

mv jdk1.6.0_181 jdk

rm -rf jdk-6u181-linux-x64.bin

To verify: 

cd $ORACLE_HOME/jdk/bin

java –version

Startup the database and listener.

Run utlrp.sql script and check that all database components are valid:

SQL> @?/rdbms/admin/utlrp.sql

SQL> select * from dba_registry;

Also, check database alert log file …just in case.

If the database has “JAVA” component you can follow the steps described in this procedure for “verification”

How To Determine The JDK Version Used by the Oracle JVM in the Database (Doc ID 131872.1)