Secunia Research has discovered a weakness in Sun Java Plugin, allowing malicious web sites to write arbitrary content to a file with a predictable name.

The problem is that the plugin creates temporary files for class files using a file name which becomes predictable when referenced using the old 8dot3 file schema (FAT16/DOS support).

The temporary file creation in itself is not a vulnerability and should not pose any risk to the system. However, combined with certain Microsoft Internet Explorer functionality and vulnerabilities this can be exploited to compromise a vulnerable system.

The weakness has been confirmed in version 1.5.0 (build 1.5.0_01-b08). Other versions may also be affected.

Solution
Change the default directory for Temporary Internet Files (this may affect functionality):
Further details available to Secunia VIM customers

Provided and/or discovered by
Andreas Sandblad, Secunia Research.

Changelog
Further details available to Secunia VIM customers

Original Advisory
Secunia Research:
http://secunia.com/secunia_research/2004-7/

Other references
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers