A security vulnerability in Java Web Start may allow an untrusted application to elevate its privileges. For example, an application may grant itself permissions to read and write local files that are accessible to the user running the Java Web Start application.

Sun acknowledges, with thanks, the Fujitsu security team, for bringing this issue to our attention.

This issue can occur in the following releases:

• Java Web Start in JDK and JRE 5.0 Update 10 and earlier for Windows, Solaris and Linux
• Java Web Start in SDK and JRE 1.4.2_13 and earlier for Windows, Solaris and Linux

To determine the version of Java installed on a system, the following command can be used:

    % java -fullversion
    java full version "1.5.0_02-b09"

There are no reliable symptoms that would show the described issue has been exploited.

To workaround this issue, users should avoid using Java Web Start with untrusted applications, and may also wish to temporarily disable the use of Java Web Start.

To disable Java Web Start applications from being automatically launched from a web browser, the following steps can be performed:

For Internet Explorer:

1. Right click on the "Start" button and select "Explore"
2. In the "Start Menu" window, select "Tools" => "Folder Options"
3. From the "Folder Options" window, select the "File Types" tab
4. From the "Registered File Types" window, scroll down and locate the "JNL - JNLP File"
5. Select the "JNLP - JNLP File" and click the "Delete" button

For Mozilla:

1. Select "Preferences" under the browser's "Edit" menu
2. In the "Preferences" window, select "Helper Applications" located under the "Navigator" category
3. Under "Files types", scroll down and locate "application/x-java-jnlp-file"
4. Select "application/x-java-jnlp-file" and click the "Remove" button

Note 1: On Microsoft Windows, applications may also be launched from the desktop icon or Start Menu if a shortcut was previously created for an application. Unknown applications should not be launched through the desktop icon or the Start Menu. Shortcuts can be removed by using the Java Web Start Application Manager through the "Application/Remove Shortcut" menu item.

For more information, see:

• http://java.sun.com/j2se/1.5.0/docs/guide/javaws/developersguide/overview.html#jws

Note 2: It is also possible to launch applications through the command line in Windows, Solaris, and Linux. Unknown applications should not be launched through the command line. Sites may consider renaming the Java Web Start launcher ("javaws.exe" for Windows and "javaws" for Solaris and Linux) to prevent Java Web Start from launching.

The launcher can be found at:

Windows:

    C:\Program Files\java\j2re1.5.0\javaws\javaws.exe

Solaris (if installed using pkg):

    /usr/bin/javaws

Linux (if installed using rpm):

    /usr/java/jre1.5.0/bin/javaws

This issue is addressed in the following releases:

• Java Web Start in JDK and JRE 5.0 Update 11 or later
• Java Web Start in SDK and JRE 1.4.2_14 or later

J2SE 5.0 is available for download at the following links:

• http://java.sun.com/j2se/1.5.0/download.jsp

J2SE 5.0 Update 11 for Solaris is available in the following patches:

• J2SE 5.0: update 11 (as delivered in patch 118666-11 or later)
• J2SE 5.0: update 11 (as delivered in patch 118667-11 or later (64bit))
• J2SE 5.0_x86: update 11 (as delivered in patch 118668-11 or later)
• J2SE 5.0_x86: update 11 (as delivered in patch 118669-11 or later (64bit))

J2SE 1.4.2 is available for download at the following link:

• http://java.sun.com/j2se/1.4.2/download.html

Note: It is recommended that affected versions be removed from your system. For more information, please see the installation notes on the respective java.sun.com download page and the following for the Windows platform:

• http://java.com/en/download/help/uninstall_java.xml

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