Apple QuickTime Player H.264 Codec Remote Integer Overflow

[Piotr Bania <bania.piotr () gmail com>]

        Apple QuickTime Player H.264 Codec Remote Integer Overflow
        by Piotr Bania <bania.piotr () gmail com>
        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