Re: Windows Heap Overflows In General

From: Vizzy (vizzyat_private)
Date: Mon Dec 02 2002 - 04:49:52 PST

  • Next message: Brett Moore: "RE: Windows Heap Overflows In General"

    Monday, December 02, 2002, 2:03:04 AM, you wrote:
    
    BM> *) Remember with heap based overflows you can write multiple sets of 4
    BM> bytes. It's not the registers you are overflowing, but a structure. What do
    BM> the other structure bytes control? Size does matter!
    Well, it's not always possible.
    
    What if you can overwrite only one free chunk structure?
    Then, possibility to overwrite choosen 4 bytes will occur in a call to free(),
    when *BK (previous free chunk pointer) would be replaced with the offset to a
    newly free()'ed one, containing our supplied data.
    
    -- 
    have phun,
     Vizzy 
    



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