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Apple QuickTime Player H.264 Codec Remote Integer Overflow




        Apple QuickTime Player H.264 Codec Remote Integer Overflow
        by Piotr Bania <bania.piotr@xxxxxxxxx>
        http://www.piotrbania.com
        All rights reserved.


        Severity:               Critical - potencial remote code execution.

        CVE:                    CVE-2006-4386

Orginal URL: http://piotrbania.com/all/adv/quicktime-integer-overflow-h264-adv-7.1.txt


        Software affected:      Tested on QucikTime 7.1 (Windows version), with
                                all newest add-ons.

                                Versions for Mac OS X v10.3.9 and later, 
Windows XP/2000
                                are also vulnerable.





        0.   DISCLAIMER

Author takes no responsibility for any actions with provided informations or codes. The copyright for any material created by the author is reserved. Any
        duplication of codes or texts provided here in electronic or printed
        publications is not permitted without the author's agreement.

        I.   BACKGROUND

        Apple QuickTime Player is one of the Apple QuickTime components
        used by hundreds of millions of users.


        II.  DESCRIPTION

        Apple QuickTime Player is reported prone to remote integer overflow
vulnerability (exploitable via remotely originated content). The overflow
        occurs in the H.264 codec.

        
        Vulnerable code:

6825a28f 668b4806 mov cx,[eax+0x6] ; cx = controled by attacker 6825a293 660fb6d5 movzx dx,ch ; dx = 0x00XX (XX - controled by attacker)
        6825a297 8af1             mov     dh,cl                 ; dx = 0xXXXX 
(-//-)
        6825a299 8bca             mov     ecx,edx               ; ecx = edx
        6825a29b 6681f90001       cmp     cx,0x100              ; compare cx 
with 0x100
6825a2a0 7f3d jg QuickTimeH264!JVTCompComponentDispatch+0x917c (6825a2df) ; (*1*)
        6825a2a2 0fbfd1           movsx   edx,cx                ; (*2*)
        6825a2a5 8bca             mov     ecx,edx
        6825a2a7 8bd9             mov     ebx,ecx
        6825a2a9 c1e902           shr     ecx,0x2
        6825a2ac 8d7008           lea     esi,[eax+0x8]
        6825a2af 8d7c2418         lea     edi,[esp+0x18]
        6825a2b3 f3a5             rep  movsd ds:00fb8000=????????


*1 - JG jumps, takes care of the sign so in this case we have an security check for upper bounds, but when cx is a negative number this check is bypassed. No lower bounds
             checks were applied - bad.

*2 - Due to the bypass of the point *1 EDX is now CX extended by sign (in this case its negative), EDX now looks like 0xFFFFXXXX, the integer is overflowed and rep movsd causes an memory corruption (obvious fact is that ECX is related to EDX).
                


        Debugger output:

eax=00fb2028 ebx=ffffc9c9 ecx=3fffda7e edx=ffffc9c9 esi=00fb8000 edi=00141688 eip=6825a2b3 esp=0013b6a0 ebp=0013b8c4 iopl=0 nv up ei pl nz ac po nc cs=001b ss=0023 ds=0023 es=0023 fs=0038 gs=0000 efl=00010216 *** ERROR: Symbol file could not be found. Defaulted to export symbols for E:\Quicktime\QTSystem\QuickTimeH264.qtx -
        QuickTimeH264!JVTCompComponentDispatch+0x9150:
6825a2b3 f3a5 rep movsd ds:00fb8000=???????? es:00141688=00000000


        The vulnerability may lead to remote code execution when specially
        crafted video file (MOV file) is being loaded.

        
        III. POC CODE

        Due to severity of this bug i will not release any proof of concept
        codes for this issue.

        IV.  VENDOR RESPONSE

        Check: http://docs.info.apple.com/article.html?artnum=61798