Re: Apple Safari 4 Beta feeds: URI NULL Pointer Dereference Denial of, Service Vulnerability

[Jubei Trippataka <vpn.1.fanatic () gmail com>]

On Fri, Feb 27, 2009 at 5:04 PM, bob jones <bholdaaa () gmail com> wrote:

> http://uninformed.org/?v=4&a=5&t=sumry
This exploitation relies on the ability to have the top-level UEF point to
an arbitrary address which hopefully you have the ability to control. The
NULL pointer is only used as a mechanism to trigger the exception necessary
to execute code where the handler now points. This doesn't need to be a NULL
deref, it can be any unhandled exception. I guess you could compare the NULL
pointer in this situation to a memory leak necesary to exploit another
condition. The memory leak itself wouldn't be called a vulnerability, it's
just used instrumentally to assist in exploitation. In this paper the NULL
pointer is used to assist in the exploitation of a hijacked UEF by
triggering the unhandled exception.

My original point stands, the NULL pointer dereference can be used to assist
in another explotiation, but in itself is not a vulnerability.

Do you disagree?

-- 
ciao

JT

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