Someone on the IE security team forwarded me a document that had additional details. So here, for your enjoyment, is a chart listing the default settings for each security level. To answer the newsgroup poster, "medium" and "medium-high" aren't the same.

About the formatting: to get it to fit within the width of the blog's text section, I've made some abbreviations.

In a few cases, the table shows a number rather than D or E or P; below the table is a description of each such entry.

At the very bottom of this post I've included the settings from the privacy tab, too.

Note: these settings reflect those for Internet Explorer 7 on Vista SP1. Please see the MDSN link above for differences between IE 6 and IE 7.

.NET Framework

.NET Framework-reliant components

     1 = High safety

ActiveX controls and plug-ins

Downloads

Enable .NET Framework setup

Miscellaneous

     1 = Prohibit downloads from software update channels
     2 = Cache content downloaded from software update channels
     3 = Automatically install software updates

Scripting

User authentication

     1 = Prompt the user for name and password
     2 = Automatic logon only in intranet zone
     3 = Automatic logon with current user name and password

Privacy settings (on the "Privacy" tab)

The session took place at the beginning of Partner Day. The “regular” conference sessions actually begin tomorrow. Today is spent focusing on partner issues and enablement.

The panel for this session included:

• Mark Chuang Group Manager, Product Marketing, VMware, Inc.
• Kenon Owens Staff Systems Engineer, VMware, Inc.

You have to remember that most of the Partners here are not vendors like ScienceLogic, but big and small shops that are selling IT, networking and now virtualization solutions into end-customer environments. For these guys, understanding what virtualization partner programs and tools are at NetApp, for example, is very useful. And many of these companies are already selling Microsoft software and surrounding services for Microsoft products. So if you’re VMware, what’s the message to these partners in the face of the Microsoft juggernaut?

Microsoft to partners: “You may not like to admit it, but you’re probably already in bed with us.”

VMware to partners: “Our hypervisor technology outperforms Hyper-V and Xen, especially at scale. And anyway, it’s not about the battle at the hypervisor. It’s about the V-services on top of the hypervisor – VMotion, Storage VMotion, DRS, etc.”

Interesting and what we all already know, or think we know. The scale issue is an interesting one – too soon for Hyper-V and who uses Xen? But also interestingly enough, no announcement or even talk about extending VMware management tools to other hypervisors. The point, as the VMware product marketing guy made a point of saying, is that the question they needed to answer used to be “Why Virtualization?” and now it’s “Why VMware?”.

One more tidbit – this survey run by VMware asking their customers:

What are the top 6 apps you are running on VMware today

• IIS
• Apache
• Active Directory
• SQL Server
• Sharepoint
• Exchange

That means, 5 of 6 are Microsoft applications. Certainly it makes it even more challenging for VMware to navigate a path here.

The change since 2004 – would have talked about why virtualize. And now why VMware. (Duh.)

Talking to partners – many of which already have a successful Microsoft business. How VMware enhances your existing Microsoft business.

Top 6 apps running on VMware today (5 of 6 are Microsoft applications)

• IIS
• Apache
• AD
• Sql server
• Sharepoint
• Exchange

Source: VMware survey

Esxi - VMware – true thin hypervisor; maximizes resources utilization (over 100% memory commitment – allows avg of 2:1 memory overcommit) – host system memory is usually the resource bottleneck – plus Advanced Scheduler runs VMs better under load and to a greater capacity (hard to show this part); performance acceleration – using binary translation (32bit), para-virtualization and Hardware Assist (for 64-bit)

(rvi – rapid virtualization indexing)

No parent partition that all hypervisors have to go through

Vs ms/xen

Parent partition – dom 0 => potentially problem at scale; i/o that could be a bottleneck

Hyper-v SPECjbb comparison

= 9 vms on VMware and hyper-v hypervisors

Outperform (CPU) by 50% - general purpose scheduler isn’t able to keep up? “got to be”

(cpu only test)

Also used VMmark – to demonstrate again that VMware is performance tuned and designed to run at scale vs Hyper-V

Size Does Matter:

Vmware ESXi: 32MB

Hyper-v – 2.6 GB

Xen – 1.2 GB

Hyper-V uses Microsoft Server Core – so the last two Patch Tuesdays had to make changes to Server Core (nothing to do with Hyper-V) but service interruption for Hyper-V.

VMware VMsafe – “Provides an unprecedented level of security” “virtual is more secure than Real” (uh oh – clearly didn’t read about the

*****************

VMware TEST:512 mb vms on server w/ 4gb ram –

7 vms - xensource (w/no memory overcommit)

6vms – hyper-v before error (w/no memory overcommit)

14vms - w/memory overcommit and management

Running sql io sim – heavy workloads

TCO – not just license; now ESXi is free – so hardware

809 - ESXi

871 – vi3 foundation ($995)

1168- vi3 enterprise ($5750)

1621 – hyper-v – 2x cost because of hw

Xen – 1618

Memory overcommit (89% in production vs. test/dev)

Survey – 37% of respondents at 2:1 RATIO OR HIGHER; real average is around 1.8: 1

*********************

This guy Mark sounds like a used car salesman:

“Always On, On Demand Data Center”

Hypervisor is very important but what is more important are the v-services on top of this. Manage shared, pooled resources. “Value Above the Hypervisor”

How does all this save “your customers” $$?

VMotion – saves cost on planned maintenance: no more overtime, no more time scheduling maintenance windows (see cost framework below)

10 (# of servers) x 6 (@ of updates) x [ (overtime cost 2hrs x $150/hr) + (scheduling downtime # of apps per server 15 x time spend scheduling per app 0.75 hr x $50/hr)] = $58,500

Same thing with using VMware Storage VMotion

Overtime cost + scheduling downtime + planning move + alternative tool cost - $68,750 (2.5 TeraBytes)

The Value of High Availability

- cost of lost business, lost work

- cost of lost productive time

4 hours of downtime x # of users per vm 10 x number of vms per host 15 x cost of user productive time $50/hr x failures per year in 10-host cluster 2 = $60K

(10 servers, 150 vms)

SAVINGS (using enterprise version)

Update management 149,760

HA 60K

DRS, VMotion Storage VMotion 187,250

808,259 – hw, power cooling, etc.

So I put together a simple class that holds an XmlDocument and implements ISerializable and called it SerializableXmlDocument. I'm sharing the source code here in the hopes that

a) somebody will find it useful, and

b) somebody smarter than I am will point out how I screwed it up and help me make it better.

SerializableXmlDocument includes implicit conversion operators to make it easy to convert to/from an XmlDocument. It holds the actual document in a property called Value. This "isomorph" pattern is one that I picked up from Craig.

While writing this code, I also wrote a helpful extension method for getting a byte array out of a MemoryStream that is exactly the length of the data written to the stream so far (CopyUpToSeekPointer). So don't go looking in the docs for MemoryStream for this method :) This is obviously not the most efficient way to consume bytes written to a MemoryStream since it copies the data into a new byte array, but it's very convenient in many scenarios.

Here is SerializableXmlDocument.cs:

using System;
using System.Runtime.Serialization;
using System.Xml;
using System.IO;

namespace Pluralsight.Samples
{
    [Serializable]
    public class SerializableXmlDocument : ISerializable
    {
        public SerializableXmlDocument() { }
        public SerializableXmlDocument(XmlDocument value)
        {
            this.Value = value;
        }

        public XmlDocument Value { get; set; }

        #region ISerializable implementation
        public SerializableXmlDocument(SerializationInfo info,
                                       StreamingContext context)
        {
            byte[] serializedData = (byte[])info.GetValue("doc",
                typeof(byte[]));
            if (null != serializedData)
                this.Value = Deserialize(serializedData);
        }

        public void GetObjectData(SerializationInfo info,
                                  StreamingContext context)
        {
            byte[] serializedData = null;
            if (null != Value)
                serializedData = Serialize(Value);
            info.AddValue("doc", serializedData);
        }
        #endregion

        #region implicit conversion to/from XmlDocument
        public static implicit operator SerializableXmlDocument(
            XmlDocument doc)
        {
            return new SerializableXmlDocument(doc);
        }
        public static implicit operator XmlDocument(
            SerializableXmlDocument sdoc)
        {
            return sdoc.Value;
        }
        #endregion

        #region Xml serialization helper methods
        private static byte[] Serialize(XmlDocument doc)
        {
            MemoryStream stream = new MemoryStream();
            doc.Save(stream);
            return stream.CopyUpToSeekPointer();
        }
        private static XmlDocument Deserialize(byte[] serializedData)
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(new MemoryStream(serializedData, false));
            return doc;
        }
        #endregion
    }
}

...and here's the CopyUpToSeekPointer extension method for MemoryStream:

using System;
using System.IO;

namespace Pluralsight.Samples
{
    public static class MemoryStreamExtensionMethods
    {
        public static byte[] CopyUpToSeekPointer(
            this MemoryStream stream)
        {
            // copy only the part of the buffer
            // that contains the serialized document
            long length = stream.Position;
            byte[] buffer = stream.GetBuffer();
            byte[] result = new byte[length];
            for (int i = 0; i < length; ++i)
                result[i] = buffer[i];
            return result;
        }
    }
}

...and here's a sample object that uses SerializableXmlDocument:

using System;

namespace Pluralsight.Samples
{
    [Serializable]
    public class Item
    {
        public string Name { get; set; }
        public SerializableXmlDocument Data { get; set; }

        public void Print()
        {
            Console.WriteLine("Name: {0}", Name);
            Console.WriteLine(Data.Value.OuterXml);
        }
    }
}

...and here's a sample program that creates an instance of Item, serializes it, then deserializes it, printing diagnostics along the way to show that it's working properly.

using System;
using System.Xml;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;
using Pluralsight.Samples;

class DemoProgram
{
    static void Main(string[] args)
    {
        XmlDocument doc = new XmlDocument();
        doc.LoadXml("<root><child>text</child></root>");

        Item item = new Item
        {
            Name = "Testing 123",
            Data = doc,
        };

        // print object before serialization
        item.Print();

        BinaryFormatter formatter = new BinaryFormatter();
        MemoryStream stream = new MemoryStream();
        formatter.Serialize(stream, item);

        byte[] serializedItem = stream.CopyUpToSeekPointer();

        Console.WriteLine("Serialized data (base64): {0}",
            Convert.ToBase64String(serializedItem));

        item = (Item)formatter.Deserialize(
            new MemoryStream(serializedItem, false));

        // print object after deserialization
        item.Print();
    }
}

Here's the output of the previous sample program:

Flame away!

My favorite talk, as expected, was the Sotirov/Dowd talk on How To Impress Girls With Browser Memory Protection Bypasses. The attack is a conceptually simple, yet completely reliable technique for exploiting vulnerabilities in web browsers. Of course, the media has sensationalized the impact of their findings, but ultimately, this is still significant as far as browser-based exploits are concerned. It’s worth mentioning that part of the technique allowing them to load a .NET DLL at an arbitrary location under Vista was reliant on an implementation bug wherein the OS disables ASLR if the version in the .NET COR header was below a certain value. However, the address space spraying and stack spraying techniques are likely to be extended to other platforms utilizing similar memory protection mechanisms.

As for the girls? I can report first-hand that the ladies at TAO on Wednesday night were hanging on Alex’s every word. They were particularly impressed when he whipped out the laptop for a live demo. Unfortunately, none of the dozen iPhone owners in the immediate vicinity thought to snap a picture (too busy Twittering). Oh well.

I also enjoyed Hovav Shacham’s talk on return-oriented programming. Simply put, he described a generalization of the return-to-libc shellcode approach with the intent to demonstrate that one could achieve Turing-complete computation using “found code” in process images. By chaining together series of mini-computations ending in return (RET) instructions, it was possible to build higher-level programming constructs such as branches and loops. The nature of the x86 instruction set provides some flexibility because instructions are interpreted differently depending on how you align the instruction pointer (i.e. the old shellcode trick of searching the process image for any JMP EBX instruction and using that as your EIP). In RISC architectures such as SPARC, however, you don’t have that luxury; if your %pc isn’t aligned properly you get a bus error. So it was quite interesting to see that they were able to extend the concept to RISC. The practicality of the attack technique is limited by the fact that the shellcode is tuned to a particular binary image — if the shellcode was built using instructions extrapolated from glibc 2.3.5, it won’t work for a system running glibc 2.4.

I thought Scott Stender’s talk on Concurrency Attacks in Web Applications was interesting as well. In a nutshell, spewing thousands of simultaneous requests at web application transactions that are not thread-safe can create interesting problems. In the presentation, Scott ran his demo against a VM running on the attack machine. I found myself wondering how effective the same attack would be over the Internet — would it be significantly less reliable (or not at all)? Race conditions are generally easier to exploit locally than remotely due to more predictable execution conditions. Certainly this is an under-tested vulnerability class though.

One presentation I wasn’t able to attend but want to follow up on is Nate McFeters, John Heasman, and Rob Carter’s talk which discussed the GIFAR attack I’ve been hearing so much about lately. The gist is that you can create a file that is both a valid GIF and a valid JAR, then use some Java applet tricks to initiate HTTP requests on behalf of the victim.

Finally, the Pwnie Awards didn’t fail to disappoint. Drama ensued over the Most Overhyped award, but at least this year some of the winners showed up to claim their awards! Halvar rapping Symantec lyrics was also quite memorable.

All in all, a fun and informative week, but as usual, I was relieved to get the hell out of Vegas and head home on Friday morning.

P.S. For a much more entertaining BlackHat/Defcon Recap, read Jennifer Jabbusch’s account of the week’s events. It’s my favorite one so far!