Re: EEYE: RealPlayer pnen3260.dll Heap Overflow

[Chenghuai Lu <luchenghuai () yahoo com>]

Hi Marc and all,

I have a question here.

> The code in pnen3260.dll among other things is
> responsible for handling
> .rm files. The vulnerability is triggered by setting
> the length field of
> the VIDORV30 data chunk to 0xFFFFFFF8 - 0xFFFFFFFF
> this will cause an
> integer overflow which leads to a small block of
> memory being allocated,
> we call this movie from a SMIL file to handle the
> initial exception,
> eventually overflowing the buffer.

I check the Real Media file format at:
http://home.pcisys.net/~melanson/codecs/rmff.htm

According to what I understand, a data chunk has a
4-byte object_id as "DATA". This makes me a little
confused. What does a VIDORV30 data chunk mean? How do
I differentiate a general data chunk from a VIDORV30
data chunk?

Thank you in advance for any advice.




                
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