From: marc at eeye.com (Marc Maiffret)
Subject: EEYE: Microsoft RPC Heap Corruption Vulnerability - Part II

1.0.4 is not the latest version. Version 1.1.0 is the latest. Upgrade to
that.

Again, if you think you have found a bug just contact us and we can help you
out.

Signed,
Marc Maiffret
Chief Hacking Officer
eEye Digital Security
T.949.349.9062
F.949.349.9538
http://eEye.com/Retina - Network Security Scanner
http://eEye.com/Iris - Network Traffic Analyzer
http://eEye.com/SecureIIS - Stop known and unknown IIS vulnerabilities

| -----Original Message-----
| From: full-disclosure-admin@...ts.netsys.com
| [mailto:full-disclosure-admin@...ts.netsys.com]On Behalf Of
| Jeff.Urnaza@...rydennison.com
| Sent: Wednesday, September 10, 2003 1:26 PM
| To: Full-Disclosure
| Subject: Re: [Full-Disclosure] EEYE: Microsoft RPC Heap Corruption
| Vulnerability - Part II
|
|
|
| The version number in eEye's supposed *new* scanner is the same version
| number  as the one they release for the previous RPC exploit, v1.0.4.  In
| my initial tests of the scanner, it did not find any vulnerable hosts for
| the new RPC security hole on my network, except the ones that I already
| patched .....  strange .... looks like someone goofed on this one .....
|
| J
|
|
|
|
|
|                       "Marc Maiffret"
|
|                       <marc@...e.com>                    To:
|  "Full-Disclosure" <full-disclosure@...ts.netsys.com>
|                       Sent by:                           cc:
|
|                       full-disclosure-admin@...ts        Subject:
|  [Full-Disclosure] EEYE: Microsoft RPC Heap Corruption
|                       .netsys.com
| Vulnerability - Part II
|
|
|
|
|                       09/10/2003 10:50 AM
|
|
|
|
|
|
|
|
|
| Here we go again. :-o
|
| -Marc
| --------
| Microsoft RPC Heap Corruption Vulnerability - Part II
|
| Release Date:
| September 10, 2003
|
| Severity:
| High (Remote Code Execution)
|
| Systems Affected:
| Microsoft Windows NT Workstation 4.0
| Microsoft Windows NT Server 4.0
| Microsoft Windows NT Server 4.0, Terminal Server Edition
| Microsoft Windows 2000
| Microsoft Windows XP
| Microsoft Windows Server 2003
|
| Description:
|
| eEye Digital Security has discovered a critical remote vulnerability in
| the
| way Microsoft Windows handles certain RPC requests. The RPC (Remote
| Procedure Call) protocol provides an inter-process communication mechanism
| allowing a program running on one computer to execute code on a remote
| system.
|
| A vulnerability exists within the DCOM (Distributed Component Object
| Model)
| RPC interface. This interface handles DCOM object activation requests sent
| by client machines to the server.
|
| Note: this vulnerability differs from the vulnerability publicized in
| Microsoft Bulletin MS03-026.
| (http://www.microsoft.com/technet/security/bulletin/MS03-026.asp)
| This is a new vulnerability, and a different patch that must be installed.
|
| By sending a malformed request packet it is possible to overwrite various
| heap structures and allow the execution of arbitrary code.
|
| Technical Details:
|
| The vulnerability can be replicated with a DCERPC "bind" packet, followed
| by
| a malformed DCERPC DCOM object activation request packet. Issuing the API
| function CoGetInstanceFromFile can generate the required request. By
| manipulating the length fields within the activation packet, portions of
| heap memory can be overwritten with data which may be user-defined.
|
| Sending between 4 and 5 activation packets is generally sufficient to
| trigger the overwrite.
|
| Upon sending the sequence of packets we were able to continually cause an
| exception within the usual suspect RtlAllocateHeap:
|
| PAGE:77FC8F11                 mov     [ecx], eax
| PAGE:77FC8F13                 mov     [eax+4], ecx
|
| We control the values of the registers eax and ecx. We can write an
| arbitrary dword to any address of our choosing.
|
| Execution of code can be achieved through a number of means -- the
| unhandledexceptionfilter or a PEB locking pointer for instance. For this
| specific vulnerability the best route was to overwrite a pointer within
| the
| writeable .data section of RPCSS.DLL :
|
| .data:761BC254 off_761BC254    dd offset loc_761A1AE7  ; DATA XREF:
| sub_761A19EF+1C_r
| .data:761BC254                                         ;
| sub_761A19EF+11D_w
| ...
| .data:761BC258 off_761BC258    dd offset loc_761A1B18  ; DATA XREF:
| sub_761A19EF+108_w
| .data:761BC258                                         ; sub_761A1DCF+13_r
| ...
|
| At runtime these two pointers reference RtlAllocateHeap and RtlFreeHeap
| respectively. By overwriting offset 0x761BC258 with our chosen EIP value,
| we
| control the processor directly after the heap overwrite. The added benefit
| in choosing this pointer is we have data from our received packet at
| ebp->10h which we may modify to our liking, within reason. There is one
| small obstacle that must be overcome. The first word value at that address
| is the length field of our packet, this field must translate to an opcode
| sequence that will allow us to reach our data that follows.
|
| Protection:
| Retina Network Security Scanner has been updated to identify this
| vulnerability.
| http://www.eeye.com/html/Products/Retina/index.html
| Also our FREE RPC scanner tool has been updated to check for this second
| vulnerability.
| http://www.eeye.com/html/Research/Tools/RPCDCOM.html
|
| Vendor Status:
| Microsoft has released a patch for this vulnerability. The patch is
| available at:
| http://www.microsoft.com/technet/treeview/?url=/technet/security/b
| ulletin/MS
|
| 03-039.asp
|
| Credit:
| Discovery: Barnaby Jack
| Additional Research: Barnaby Jack and Riley Hassell.
|
| Greetings:
| Thanks to Riley, and utmost respect to all of the eEye massive - masters
| of
| the black arts.
| Greets to all the new people I met in Vegas this year, especially the NZ
| crew, and many thanks to K2 (da bankrolla.) :)
| "This is my line. This is eternal." -AFI
|
| Copyright (c) 1998-2003 eEye Digital Security
| Permission is hereby granted for the redistribution of this alert
| electronically. It is not to be edited in any way without express consent
| of
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|
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| are
| NO warranties with regard to this information. In no event shall the
| author
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|
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| Please send suggestions, updates, and comments to:
|
| eEye Digital Security
| http://www.eEye.com
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|
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