Last Stage of Delirium wrote:
Hello,
We have found a security vulnerability in the SUN's implementation of the Java Virtual Machine, which affects the following SDK and JRE releases: - SDK and JRE 1.4.1_03 and earlier - SDK and JRE 1.3.1_08 and earlier - SDK and JRE 1.2.2_015 and earlier.
The following applet tests for this vulnerability:
------------------------------------------------------------------ import java.applet.Applet; import java.awt.Graphics; import java.lang.Class; import java.security.AccessControlException;
public class Simple extends Applet {
StringBuffer buffer;
public void init() {
buffer = new StringBuffer();
}public void start() {
ClassLoader cl = this.getClass().getClassLoader();
try {
Class cla = cl.loadClass("sun/applet/AppletClassLoader"); // Note the slashes
addItem("No exception in loadClass. Vulnerable!");
} catch (ClassNotFoundException e) {
addItem("ClassNotFoundException in loadClass - " + e);
} catch (AccessControlException e) {
addItem("AccessControlException in loadClass - Not Vulnerable!");
}
}
void addItem(String newWord) {
System.out.println(newWord);
buffer.append(newWord);
repaint();
} public void paint(Graphics g) {
//Draw a Rectangle around the applet's display area.
g.drawRect(0, 0, size().width - 1, size().height - 1); //Draw the current string inside the rectangle.
g.drawString(buffer.toString(), 5, 15);
}
}
----------------------------------------------------------------This test can be found here: http://bcheck.scanit.be/bcheck/applet.html
If Sun Java VM is installed, the applet runs and says if VM is vulnerable or not.
I am loading sun.applet.AppletClassLoader, but it could be any other class from sun. package tree.
I don't know how this bug is exploitable, because whenever I try to do anything at all with a class loaded this way, for example, create an instance of it or call methods, I get SecurityManager's exceptions. Gotta wait patiently until LSD releases more details.
I've tested Internet Explorer 6 and Mozilla Firebird. Internet Explorer is exploitable if confgured to use Sun Java VM instead of Microsoft VM.
Alla.
