HELP! * YELLOW=global GREY=local Global HTML version of Foils prepared 4 February 97

Foil 48 Security Concerns for Applets

From Feb 3 Delivered Lecture for Course CPS616 -- Java Lecture 4 -- AWT Through I/O CPS616 spring 1997 -- Feb 3 1997. by Nancy McCracken * See also color IMAGE
Secs 76.3
One aspect of Java security is language restrictions designed not to let a Java applet or application access memory on the machine outside of its own space.
Applets have additional restrictions:
  • they can never run a local executable program;
  • they cannot communicate with any host other than the server from which they were downloaded (the originating host);
  • they cannot read or write to the local computer's file system, except through the browser mechanism;
  • they cannot find out information about the local computer (see table on next slide for details).
As of summer 1996, no known applets have seriously broken security to steal client information or trash the local disk. Exceptions:
  • applets have been written to use up arbitrary amounts of client cpu.
  • applets with native code can trash the local disk. So far, native code is disallowed on publicly released browsers.


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