Knowledgebase
Java 7(1.7) Security Exceptions - How To
Posted by Tony Rosa on 18 May 2015 10:18 AM

From the Oracle Java Support site..

https://www.java.com/en/download/help/java_blocked.xml

SYMPTOMS

Starting with Java 7 Update 51, trying to run Java applications generates messages

-Java applications are blocked by your security settings.
-Missing Application-Name manifest attribute
-Missing required Permissions manifest attribute in main jar

 

CAUSE

Java has further enhanced security to make the user system less vulnerable to external exploits. Starting with Java 7 Update 51, Java does not allow users to run applications that are not signed (unsigned), self-signed (not signed by trusted authority) or that are missing permission attributes.

Risks involved in running applications
Unsigned application
An application without a certificate (i.e. unsigned apps), or missing application Name and Publisher information are blocked by default. Running this kind of application is potentially unsafe and present higher level of risk.
Self-signed application (Certificate not from trusted authority)
An application with self-signed certificate is blocked by default. Applications of this type present the highest level of risk because publisher is not identified and the application may be granted access to personal data on your computer.
Jar file missing Permission Attribute
Permissions Attribute verifies that the application requests the permission level that developer specified. If this attribute is not present, it might be possible for an attacker to exploit a user by re-deploying an application that is signed with original certificate and running the application at a different privilege level.
SOLUTION

The application that you are running is blocked because the application does not comply with security guidelines implemented in Java 7 Update 51.

Contact the developer or publisher of this application and let them know about the application being blocked. You can refer them to these links that provide information about implementing secure practices in the code for the application.

JAR File Manifest Attributes for Security
Java SE 7 Security Documentation
Secure Coding Guidelines for the Java Programming Language, Version 4.0
WORKAROUND

It is highly recommended not to run these types of applications. However if you still want to run these apps, run only if you understand the risks and implications.

As a workaround, you can use the Exception Site list feature to run the applications blocked by security settings. Adding the URL of the blocked application to the Exception Site list allows it to run with some warnings.

Steps to Add URLs to the Exception Site list
Go to the Java Control Panel (On Windows Click Start and then Configure Java)
Click on the Security tab
Click on the Edit Site List button
Click Add in the Exception Site List window

Add url to Exception Site list
Click in the empty field under the Location field to enter the URL

Example: http://www.example.com
(URL should begin with http:// or https://)

Oracle KB

 

If the URL where the applet is hosted is different from the URL of the web page from which the applet is launched, then you will need to add both the URL for the applet as well as the URL for the web page.

Example with different URLs for the applet and the web page
For Yahoo games Checkers, you would enter both URLs (The urls listed can be different depending on which host is serving the game)
http://www.games.yahoo.com
This is the url for the Yahoo games domain
http://yog36.games.sp2.yahoo.com
This is the url where the game is hosted and shown in the dialog box for the blocked application

Click OK to save the URL that you entered
Click Continue on the Security Warning dialog

 

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