[EEYEB-20051031] Apple QuickTime Malformed GIF Heap Overflow Jan 11 2006 05:40PM
Advisories (Advisories eeye com)
EEYEB-20051031 Apple QuickTime Malformed GIF Heap Overflow

Release Date:
January 10, 2006

Date Reported:
October 31, 2005

High (Code Execution)

Patch Development Time (In Days):
71 Days

High (Code Execution)


Systems Affected:
Quicktime on Windows 2000
Quicktime on Windows XP
Quicktime on Mac OS X 10.3.9

Apple iTunes on Windows 2000
Apple iTunes on Windows XP
Apple iTunes on OS X 10.3.9

eEye Digital Security has discovered a critical heap overflow in the Apple Quicktime player that allows for the execution of arbitrary code via a maliciously crafted GIF file.

This flaw has proven to allow for reliable control of data on the heap chunk and can be exploited via a web site by using ActiveX controls.

Technical Details:
When Quicktime processes the Netscape Navigator Application Extension Block of a gif file, it does not perform proper bounds checking, so it will allocate memory without checking the heap size. The heap can be overwritten in the Picture Modifier block.
The block size calculate code such as:
.text:66A339CC mov ax, [esi+0Ch]
.text:66A339D0 xor ecx, ecx
.text:66A339D2 mov [esp+34h+var_28], ecx
.text:66A339D6 mov [esp+34h+var_24], ecx
.text:66A339DA mov [esp+34h+var_20], ecx
.text:66A339DE mov [esp+34h+var_1C], ecx
.text:66A339E2 mov word ptr [esp+34h+var_10], cx
.text:66A339E7 mov [esp+34h+arg_4], eax
.text:66A339EB movsx eax, ax
.text:66A339EE mov word ptr [esp+34h+var_10+2], cx
.text:66A339F3 mov cx, [esi+8]
.text:66A339F7 movsx edx, cx
.text:66A339FA sub eax, edx
.text:66A339FC movsx edx, word ptr [esi+6]
.text:66A33A00 add eax, 3Eh
.text:66A33A03 push edi
.text:66A33A04 movsx edi, word ptr [esi+0Ah]
.text:66A33A08 sar eax, 3
.text:66A33A0B lea ebx, [esi+6]
.text:66A33A0E and eax, 0FFFFFFFCh
.text:66A33A11 sub edi, edx
.text:66A33A13 movsx edx, ax
.text:66A33A16 mov [esi+4], ax
.text:66A33A1A imul edi, edx

The allocate code is :
.text:66A33A68 push edi
.text:66A33A69 call sub_668B5B30

But when it real process data to this memory, it use real decode data to write this memory
but didn¡¯t check this heap size. This is segment of the write code function(sub_66AE0A70):
.text:66AE0B18 movsx edx, word ptr [edi+12h] ; default
.text:66AE0B1C imul edx, [edi+0Ch]
.text:66AE0B20 mov ecx, [edi+4]
.text:66AE0B23 inc word ptr [edi+16h]
.text:66AE0B27 mov eax, [esp+arg_0]
.text:66AE0B2B add edx, ecx
.text:66AE0B2D mov [eax], edx
.text:66AE0B2F mov eax, [ebp+10h]
.text:66AE0B32 test eax, eax
.text:66AE0B34 jz short loc_66AE0B62
.text:66AE0B36 mov ax, [ebp+1Ch]
.text:66AE0B3A mov edx, [ebp+0Ch]
.text:66AE0B3D movzx cx, ah
.text:66AE0B41 mov ch, al
.text:66AE0B43 mov [edx], cx
.text:66AE0B46 movsx eax, word ptr [edi+12h]
.text:66AE0B4A imul eax, [ebp+14h]
.text:66AE0B4E add eax, [ebp+10h]
.text:66AE0B51 mov cx, [ebp+18h]
.text:66AE0B55 mov [ebp+0Ch], eax
.text:66AE0B58 mov [ebp+1Ah], cx
.text:66AE0B5C mov word ptr [ebp+1Ch], 0

Vendor Status:
Apple has released a patch for this vulnerability. The patch is available via the Updates section of the affected applications.
This vulnerability has been assigned the CVE identifier CVE-2005-2340.

Fang Xing

eEye Research and especially Hugo for all his help

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