Security outfit eEye have released details for a stack buffer overflow vulnerability that affects the Java WebStart element of the Java Runtime Environment (JRE). 

The issue can be triggered when the user opens a specially crafted JNLP file is opened. It would be possible to attempt to exploit this vulnerability by sending an email with the file attached. Alternatively, an attacker could use the content type "application/x-java-jnlp-file" on downloads from a web server to have the file executed by a browser when downloaded.

If successfully exploited by an attacker the payload could be executed in the context of the user that opened the file.

The Java WebStart component is installed by default during a standard installation of the Java Runtime Environment. Sun have produced an update for JRE 5 and JRE 6, that are available here and here. Alternatively there is a workaround for the issue by removing the .jnlp file handler association from these registry keys.

HKLM\Software\Classes\.jnlp
HKLM\Software\Classes\JNLPfile
HKLM\Software\Classes\MIME\Database\Content Type\application/x-java-jnlp-file

You can get more info from eEye here in their BugTraq advisory posting.

Add this page to your favorite Social Bookmarking websites