Re: Java and buffer overflows

["Anibal Ambertin" <aambertin () securetty com ar>]

    As someone else said before, the VM/interpreter of our
java classes is who's gonna check the code in interpretation/execution
time. This message is a tipical java error message, in this case
because of an intepreter thrown exception... but actually it doesn't
mean that we can overwrite a damn byte. Actually, the VM may have
some bug, but since it's not setuid on any system by default...
    The real danger around VM's I think are the web browser's pluggins.
As any other language, the real security uses to come from designers
and developers and not from the language itself.

Cheers. Anibal Ambertin.

----- Original Message -----
From: "KF" <dotslash () snosoft com>
To: <felix () cannabis net>
Cc: <vuln-dev () securityfocus com>
Sent: Tuesday, June 25, 2002 12:40 AM
Subject: Re: Java and buffer overflows


> Not sure if this helps .... I was trying to come up with a scenario that
> passed user input to a buffer but the compiler kept barking at me so
> this is the best I can do.
>
> [root@qa5 root]# cat test.java
> class test
> {
>         public static void main(String args[])
>         {
>
>                 String[] test = new String[4];
>                 test[0] = "A";
>                 test[1] = "A";
>                 test[2] = "A";
>                 test[3] = "A";
>                 test[4] = "A";
>                 test[5] = "A";
>                 test[6] = "A";
>         }
> }
>
>
> [root@rcmqa5 root]# javac test.java
> [root@rcmqa5 root]# java test
> Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4
>         at test.main(test.java:11)
>
> -KF
>
>
> Felix Harris wrote:
>
> > > I was wondering if code written in JAVA(or .NET) is vulnerable to buffer
overflows.
> > > If yes,what are the differences in the proccess of exploiting?
> > > Any online source?
> >
> >
> > well afaik one of the main reasons for creating Java was to make it
> > a safe language, as there is no complications between pointers
> > and buffers. Buffers are also lengthchecked, and pointers dont
> > really have the required scope to be exploited. If there was an
> > exploit for a java program, it would probably exist as a bug in the
> > virtual machine, or in a call to a c/c++ program/library. IIRC, there
> > was something about zlib being exploitable?
> > --
> > Felix Harris
> > felix () cannabis net
> > I say goodbye and raindrops taste like tears
> > In the pouring rain I stand and die alone