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Blackdown Java: Applet privilege escalation


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200705-20 / blackdown-jdk,blackdown-jre
Release Date May 26, 2007
Latest Revision May 26, 2007: 01
Impact normal
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
dev-java/blackdown-jdk < >= All supported architectures
dev-java/blackdown-jre < >= All supported architectures

Related bugreports: #161835


The Blackdown JDK and the Blackdown JRE suffer from the multiple unspecified vulnerabilities that already affected the Sun JDK and JRE.

2.  Impact Information


Blackdown provides implementations of the Java Development Kit (JDK) and the Java Runtime Environment (JRE).


Chris Evans has discovered multiple buffer overflows in the Sun JDK and the Sun JRE possibly related to various AWT and font layout functions. Tom Hawtin has discovered an unspecified vulnerability in the Sun JDK and the Sun JRE relating to unintended applet data access. He has also discovered multiple other unspecified vulnerabilities in the Sun JDK and the Sun JRE allowing unintended Java applet or application resource acquisition. Additionally, a memory corruption error has been found in the handling of GIF images with zero width field blocks.


An attacker could entice a user to run a specially crafted Java applet or application that could read, write, or execute local files with the privileges of the user running the JVM, access data maintained in other Java applets, or escalate the privileges of the currently running Java applet or application allowing for unauthorized access to system resources.

3.  Resolution Information


Disable the "nsplugin" USE flag in order to prevent web applets from being run.


Since there is no fixed update from Blackdown and since the flaw only occurs in the applets, the "nsplugin" USE flag has been masked in the portage tree. Emerge the ebuild again in order to fix the vulnerability. Another solution is to switch to another Java implementation such as the Sun implementation (dev-java/sun-jdk and dev-java/sun-jre-bin).

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose "dev-java/blackdown-jdk"
# emerge --ask --oneshot --verbose "dev-java/blackdown-jre"

4.  References


Page updated May 26, 2007

Summary: This is a Gentoo Linux Security Advisory

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