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Randy's Blog on Infosec and Other Stuff

How to Monitor Active Directory Changes for Free: Using Splunk Free, Supercharger Free and My New Splunk App for LOGbinder

Fri, 02 Jun 2017 17:11:59 GMT

No matter how big or small you are, whether you have budget or not – you need to be monitoring changes in Active Directory.  There are awesome Active Directory audit solutions out there.  And ideally you are using one of them.  But if for whatever reason you can’t, you still have AD and it still needs to be monitored.  This solution helps you do just that.  

Yesterday during my webinar: How to Monitor Active Directory Changes for Free: Using Splunk Free, Supercharger Free and My New Splunk App we released a version of our Splunk App for LOGbinder.  Not only is this application free, but with the help of our just announced free edition of Supercharger for Windows Event Collection, we demonstrate the power of WEC’s Xpath filtering to deliver just the relevant events to Splunk Free and stay within the 500MB daily limit of Splunk Light’s free limitations.  It’s a trifecta free tools that produces this:

Among other abilities, our new Splunk App puts our deep knowledge of the Windows Security Log to work by analyzing events to provide an easy to use but powerful dashboard of changes in Active Directory.  You can see what’s been changing in AD sliced up

by object type (users, groups, GPOs, etc)
by domain
by time
by administrator

Too many times I see dashboards that showcase the biggest and highest frequency actors and subjects but get real – most of the time what you are looking for is the needle – not the haystack.  So we show the smallest, least frequent actors and objects too.  

Just because it’s free doesn’t mean it’s low value.  We put some real work into this.  I always learn something new about or own little AD lab environment when I bring this app up.  To make this app work we had to make some improvements to how Splunk parses Windows Security Events.  The problem with stuff built by non-specialists is that it suffices for filling in a bullet point like “native parsing of Windows Security Logs” but doesn’t come through when you get serious about analysis.  Case-in-point: Splunk treats these 2 very different fields in the below event as one:

As you can see rsmith created the new user cmartin.  But checkout what Splunk does with that event:

Whoah! So there’s no difference between the actor and the target of a critical event like a new account being created?  One Splunker tells me they have dealt with this issue by ordinal position but I'm frightened that actor and target could switch positions.  Anyway, it’s ugly.  Here’s what the same event looks like once you install our Splunk App:

That’s what I'm talking about! Hey, executives may say that’s just the weeds but you and I know that with security the devil is in the details.  

Now, you knowledgeable Splunkers out there are probably wondering if we get these events by defining them at index time.  And the answer is “no”.  I provided the Windows Security Log brains but we got a real Splunker to build the app and you’ll be happy to know that Imre defined these new fields as search time fields.  So this works on old events already indexed and more importantly doesn’t impact indexing.  We tried to do this right.

Plus, we made sure this app works whether you consume events directly from the Security log of each computer or via Windows Event Collection (which is what we recommend with the help of Supercharger). 
To learn more about the over all solution please watch the webinar which is available on demand at

For those of you new to Splunk, we’ll quickly show you how to install Splunk Free and our Splunk App.  Then we’ll show you how in 5 minutes or our free edition of Supercharger for Windows Event Collection can have your domain controllers efficiently forwarding just the relative trickle of relevant change events to Splunk.  Then we’ll start rendering some beautiful dashboards and drilling down into those events.  I'll briefly show you how this same Splunk app can also analyze SharePoint, SQL Server and Exchange security activity produced by our LOGbinder product and mix all of that activity with AD changes and plot it on a single pane of glass.

Or checkout the solution page at where there are links to the step-by-step directions.

And if you are already proficient with Splunk and collecting domain controller logs you can get the Splunk app at and look under SIEM Integration.  

For technical support please use the appropriate forum at 

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Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
5 Indicators of Endpoint Evil
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure
Live with Dell at RSA 2015

Ransomware Is Only Getting Started

Mon, 29 May 2017 16:20:01 GMT

Ransomware is about denying you access to your data via encryption. But that denial has to be of a great enough magnitude create sufficient motivation for the victim to pay. Magnitude of the denial is a factor

  • Value of the encrypted copy of the data which is a function of
    • Intrinsic value of the data (irrespective of how many copies exist)
    • The number of copies of the data and their availability
  • Extent of operations interrupted

If the motivation-to-pay is about the value of the data, remember that the data doesn’t need to be private. It just needs to be valuable. The intrinsic value of data (irrespective of copies) is only the first factor in determining the value of the criminally encrypted copy of the data. The number copies of the data and their level of availability exert upward or downward pressure on the value of the encrypted data. If the victim has a copy of the data online and immediately accessible the ransomware encrypted copies has little to know value. On the other hand, if there’s no backups of the data the value of the encrypted copy skyrockets.

But ransomware criminals frequently succeed in getting paid even if the value of the encrypted copy of data is very low. And that’s because of the operations interruption. An organization may be hit by ransomware that doesn’t encrypt a single file containing data that is intrinsically valuable. For instance, the bytes in msword.exe or outlook.exe are not valuable. You can find those bytes on billions of PCs and download them at any time from the Internet.

But if a criminal encrypts those files you suddenly can’t work with documents or process emails. That user is out of business. Do that to all the users and the business is out of business.

Sure, you can just re-install Office, but how long will that take? And surely the criminal didn’t stop with those 2 programs.

Criminals are already figuring this out. In an ironic twist, criminals have co-opted a white-hat encryption program for malicious scrambling of entire volumes. Such system-level ransomware accomplishes complete denial of service for the entire system and all business operations that depend on it.

Do that to enough end-user PCs or some critical servers and you are into serious dollar losses no matter how well prepared the organization.

So we are certainly going to see more system-level ransomware.

But encrypting large amounts of data is a very noisy operation that you can detect if you are watching security logs and other file i/o patterns which just can’t be hidden.

So why bother with encrypting data in the first place. Here’s 2 alternatives that criminals will increasingly turn to

  • Storage device level ramsomware
  • Threat of release

Storage device level ransomware

I use the broader term storage device because of course mechanical hard drives are on the way out. Also, although I still use the term ransomware, storage device level ransomware may or may not include encryption. The fact is that storage devices have various security built-in to them that can be “turned”. As a non-encryption but effective example take disk drive passwords. Some drives support optional passwords that must be entered at the keyboard prior to the operating system booting. Sure the data isn’t encrypted and you could recover the data but at what cost in terms of interrupted operations?

But many drives, flash or magnetic, also support hardware level encryption. Turning on either of these options will require some privilege or exploitation of low integrity systems but storage level ransomware will be much quieter, almost silent, in comparison to application or driver level encryption of present-day malware.

Threat of release

I’m surprised we haven’t heard of this more already. Forget about encrypting data or denying service to it. Instead exfiltrate a copy of any kind of information that would be damaging if it were released publicly or to another interested party. That’s a lot of information. Not just trade secrets. HR information. Consumer private data. Data about customers. The list goes on and on and on.

There’s already a burgeoning trade in information that can be sold – like credit card information but why bother with data that is only valuable if you can sell it to someone else and/or overcome all the fraud detection and lost limiting technology that credit card companies are constantly improving?

The data doesn’t need to be intrinsically valuable. It only needs to be toxic in the wrong hands.

Time will tell how successful this will be it will happen. The combination of high read/write I/O on the same files is what makes ransomware standout right now. And unless you are doing transparent encryption at the driver level, you have to accomplish it in bulk as quickly as possible. But threat-of-release attacks won’t cause any file system output. Threat-of-release also doesn’t need to process bulk amounts of information as fast as possible. Criminals can take their time and let it dribble out of the victim’s network their command and control systems. On the other hand, the volume of out bound bandwidth with threat of release is orders of magnitude higher than encryption-based ransomware where all the criminal needs to send is encryption keys.

As with all endpoint based attacks (all attacks for that matter?) time is of the essence. Time-to-detection will continue to determine the magnitude of losses for victims and profits for criminals.

This article by Randy Smith was originally published by EventTracker

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5 Indicators of Endpoint Evil
Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
Anatomy of a Hack Disrupted: How one of SIEM’s out-of-the-box rules caught an intrusion and beyond
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure

Just released: Randy Franklin Smith whitepaper

Fri, 19 May 2017 11:42:23 GMT

Just released: “Top 10 Ways to Identify and Detect Privileged Users by Randy Franklin Smith” white paper.

Read it online here:

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5 Indicators of Endpoint Evil
Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure
Anatomy of a Hack Disrupted: How one of SIEM’s out-of-the-box rules caught an intrusion and beyond

Work Smarter – Not Harder: Internal Honeynets Allow You to Detect Bad Guys Instead of Just Chasing False Positives

Tue, 07 Mar 2017 10:44:31 GMT

Log collection, SIEM and security monitoring are the journey not the destination. Unfortunately, the destination is usually a false positive. This is because we’ve gotten very good at collecting logs and other information from production systems, filtering that data and presenting it on a dashboard. But we haven’t gotten that good at distinguishing events triggered by bad guys from those triggered by normal every day activity.

A honeynet changes that completely.

At the risk of perpetuating a bad analogy I’m going to refer to the signal to noise ratio often thrown around when you talk about security monitoring. If you like that noise/signal concept then the difference is like putting an egg timer in the middle of time square at rush hour. Trying to hear it is like trying to pickout bad guy activity in logs collected from production systems. Now put that egg timer in a quiet room.  That’s the sound of a bad guy hitting an internal honeynet.

Honeynets on your internal network are normally very quiet. The only legitimate stuff that’s going to hit them are things like vulnerability scanners, network mapping tools and… what else? What else on your network routinely goes out and touches IP addresses that it’s not specifically configured to communicate with?

So you either configure those few scanners to skip your honeynet IP ranges or else you leverage them for as positive confirmation that your honeynet is working and reporting when it’s touched. You just de-prioritize that expected traffic to an “honorable mention” pane on your dashboard.

On the other hand, (unless someone foolishly publishes it) the bad guy isn’t going to know the existence of your honeynet or its coordinates. So as he routinely scans your network he’s inevitably going to trip over your honeynet. If you’ve done it right. But let’s talk about some of these points.

First, how would a bad guy find out about your honeynet?

  • Once he gets control of IT admin users accounts and reads their email, has access to your network and security documentation, etc. But if you have good privileged access controls this should be fairly late stage. Honeynets are intended to catch intrusions at early to mid-stage.
  • By lurking on support forums and searching the Internet (e.g. Stackoverflow, honeynet vendor support sites). It goes without saying, don’t reveal your name, company or company email address in your postings.
  • By scanning your network. It’s pretty easy to identity honey nets when you come across them – especially low-interaction honeynets which are most common. But guess what? Who cares? They’ve already set off the alarm. So this one doesn’t count.

So, honeynets are definitely a matter of security through obscurity. But you know what? We rely on security through obscurity a lot more than we think. Encryption keys are fundamentally security through obscurity. Just really, really, really, good obscurity. And security through obscurity is only a problem when you are relying on it as a preventive control – like using a “secret” port number instead of requiring an authenticated connection. Honeynets are detective controls.

But what if you are up against not just a persistent threat actor but a patient, professional and cautious one who assumes you have a honeynet and you’re listening to it. He’s going to tiptoe around much more carefully. If I were him I would only touch systems out there that I had reason to believe were legitimate production servers. Where would I collect such information? Places like DNS, browser history, netstat output, links on intranet pages and so on.

At this time, most attackers aren’t bothering to do that. It really slows them down and they know it just isn’t necessary in most environments. But this is a constant arms race so it good to think about the future. First, a bad guy who assumes you have a honeynet is a good thing because of what I just mentioned. It slows them down. Giving more time for your other layers of defense to do their job.

But are there ways you to optimize your honeynet implementation for catching the honeynet-conscious, patient attacker? One thing you can do is go to the extra effort and coordination with your network team to reserve more and smaller sub-ranges of IP addresses for your honeynet so that its widely and granularly dispersed throughout address space. This makes it harder to make a move without hitting your honey net and further reduces the assumptions that attackers usually find it safe to make such as that all your servers are in range for static addresses, workstations in another discreet range for DHCP and then another big block devoted to your honeynet.

The bottom line though is Honeynets are awesome. You get very high detection with comparatively small investment. Checkout my recent webinar on Honeynets sponsored by EventTracker who now offers a Honeynet-as-a-Service that is fully integrated with your SIEM. Deploying a honeynet and keeping it running is one thing, but integrating it with your SIEM is another. EventTracker nails both.

This article by Randy Smith was originally published by EventTracker”

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Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure
5 Indicators of Endpoint Evil
Live with Dell at RSA 2015

Tracking removable storage with the Windows Security Log

Mon, 02 Jan 2017 10:46:36 GMT

With data breaches and Snowden-like information grabs I’m getting increased requests for how to track data moving to and from removable storage such as flash drives. The good news is that the Windows Security Log does offer a way to audit removable storage access. I’ll show you how it works and since the sponsor for this post, EventTracker, has some enhanced capabilities in this area I’ll briefly compare native auditing to EventTracker.

Removable storage auditing in Windows works similar to and logs the exact same events as File System auditing. The difference is in controlling what activity is audited.

To review, with File System auditing, there are 2-levels of audit policy. First you enable the Audit File System audit subcategory at the computer level. Then you choose which folders you wish to audit and enable object level auditing on those folders for the users/groups, permissions and success/failure results that need to be monitored. For instance you can audit Read access on C:\documents for the SalesReps group.

However Removable Storage auditing is much simpler to enable and far less flexible. After enabling the Removable Storage audit subcategory (see below) Windows begins auditing all access requests for all removable storage. It’s equivalent to enabling auditing Full Control for Everyone.

As you can see auditing removable storage is an all or nothing proposition. Once enabled, Windows logs the same event ID 4663 as for File System auditing. For example the event below shows that user rsmith wrote a file called checkoutrece.pdf to a removable storage device Windows arbitrarily named \Device\HarddiskVolume4 with the program named Explorer (the Windows desktop).

How do we know this is a removable storage event and not just normal File System auditing? After all it’s the same event ID as used for normal file system auditing. Notice the Task Category above which says Removable Storage. The information under Subject tells you who performed the action. Object Name gives you the name of the file, relative path on the removable storage device and the arbitrary name Windows assigned the device the first time it was connected to this system. Process information indicates the program used to perform the access. To understand what type of access (e.g. Delete, Write, Read) was performed look at the Accesses field which lists the permissions actually used.

If you wish to track information being copied from your network to removable storage devices you should enable Audit Removable Storage via group policy on all your endpoints. Then monitor for Event ID 4663 where Task Category is Removable Storage and Accesses is wither WriteData or AppendData.

As you can see Microsoft took the most expedient route possible to providing an audit trail of removable storage access. There are events for tracking the connection of devices – only the file level access events of the files on the device. These events also do not provide the ability to see the device model, manufacturer or serial number. That device information is known to Windows – it just isn’t logged by these events since they captured at the same point in the operating system that other file access events are logged. On the other hand, EventTracker’s agent logs both connection events and information about each device. In fact EventTracker event allows you selectively block or allow access to specific devices based on policy you specify. I encourage you to check out EventTracker’s enhanced abilities.

This article by Randy Smith was originally published by EventTracker

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Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
Understanding the Difference between “Account Logon” and “Logon/Logoff” Events in the Windows Security Log
5 Indicators of Endpoint Evil
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure

Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online

Tue, 27 Dec 2016 10:16:02 GMT

Email remains one of the most heavily used communications mediums within organizations today. With as much as 75 percent of your organization’s intellectual property stored in email[1], Microsoft Exchange is for all practical purposes a treasure trove of organization’s most valuable secrets—just waiting for inappropriate access.

Regulatory bodies realize this and therefore email and compliance go hand in hand-in-hand. So IT needs to keep a watchful eye on exactly who is accessing what within Exchange Online. And that focus shouldn’t be only on the people you trust, such as those who have been granted access to a given mailbox, but on any user. IT needs to help ensure visibility into the actions of potential threat actors who might have hijacked privileged accounts. The first thing external threat actors do after infiltrating your network is attempt to identify accounts that have elevated permissions. And those accounts can have access to the sensitive information stored within Exchange Online.

For years, Microsoft has enabled an audit trail within on-premises Exchange Server. The same capability exists for Exchange Online—with some improvements to boot—giving IT organizations visibility into actions performed by administrators and regular users alike. But be forewarned: You’re largely on your own here. Microsoft has provided some functionality via administrative consoles, but the ability to successfully enable, configure, and audit Exchange Online events depends fairly heavily on PowerShell[LP1].

The challenge isn’t configuring the auditing of events; that part is simple. Rather, the challenge is finding the event or events that are pertinent to the auditing query in question. If you’ve spent any time in Event Viewer, you know how it feels to rummage through countless thousands of event entries, trying to find the one entry you’re looking for.

Microsoft has taken great strides to provide you the tools necessary to simplify the process of auditing. Still, a bit of work remains to enable, configure, and retrieve meaningful audit data.

This whitepaper explains those necessary steps and provides guidance for properly auditing changes to your Exchange Online environment within Office 365. The paper also covers ways to focus your auditing lens on the right what, who, and where so that you can quickly and accurately find answers to those sometimes difficult auditing questions. 

Auditing Experts – Quest


Understanding what’s going on within Exchange Online involves much more than the ability to centralize audit data. To truly audit such complex environments, you need a deeper understanding of each event and its detail, how audit events correlate, and what that information means to the organization—along with the ability to make the data understood.


Quest Change Auditor is the culmination of tens of thousands of hours of work dissecting every auditable event over a variety of platforms and applications. This effort turns raw, indecipherable information into intelligent detail, from which an IT organization can obtain actionable insight.


Look for auditing insights from Quest throughout this paper.

Connecting to Office 365 to Enable and Configure Auditing

The first step is to enable auditing. Auditing is disabled by default, as not every organization is required to — or even interested in — auditing what happens within Exchange Online. As previously mentioned, much of this step happens in PowerShell. You’ll need to connect to Exchange Online via PowerShell so that all commands are run against your instance of Exchange Online.

Open a PowerShell window. You don’t need to be a local admin to run Exchange commands against the cloud, but you do need appropriate permissions within Exchange Online; more on these permissions soon. To connect to Exchange Online, you’ll run four commands.

Set-ExecutionPolicy RemoteSigned

This command tells PowerShell that any scripts that are downloaded by a trusted publisher (Microsoft, in this case) can run on the local computer.

$UserCredential = Get-Credential

This command displays a login dialog box that you use to store an Office 365 admin credential (which does not necessarily need to be the same credential you used to start the PowerShell window) as a parameter for use in the third command.

$Session = New-PSSession –ConfigurationName Microsoft.Exchange –ConnectionUri -Credential $UserCredential –Authentication Basic –AllowRedirection

This command establishes a new PowerShell session with Office 365, using the provided credentials and the specified URL. The command stores all this information in the $Session variable.

Import-PSSession $Session

This command imports commands (e.g., cmdlets, functions, aliases) from the remote computer (i.e., Office 365) into the current session. At this point, you’re properly connected to Exchange Online and can begin auditing your Exchange Online environment. 

Quest Insight – What Should You Be Auditing?

Exchange Online can be configured to generate a ton of information—which, of course, means more data for you to sift through. Because you are essentially in control of how much audit data is generated, you can determine which activities to include. You can focus on three categories of audit activity:


·         Message tracking is the actual flow of messages from one user to another. At a minimum, this category can be used to show who is emailing whom, such as whether email is being sent to a competitor. On a larger scale, message tracking can be used with analytics to see how the business uses email. This tracking is useful to see how internal messaging flows; for example, from one department to another. Message tracking can also be used to see the flow of traffic in and out of the organization; for example, which domains send or receive the most email. You can use the Get-MessageTrace cmdlet to retrieve a list of messages that meet query criteria such as sender or recipient address, date range, or source IP address. This activity is most appropriate when a review of specific sent and received messages is needed in addition to a review of mailbox contents. This tracking can also be useful when connected to a SIEM solution, using keyword alerts to identify inappropriate messages.

·         Admin operations involve any actions that are taken within Office 365, including actions by your IT team or Microsoft (which maintains the Exchange Online instance). Admin operations, such as assigning permissions to a mailbox or setting up forwarding rules, can play a key role during an audit; even IT can play a role in inappropriate behaviors.

·         Non-owner mailbox access occurs whenever someone other than the owner accesses a mailbox. This category is important when sensitive information has been inappropriately accessed or forwarded, and the focus is on identifying who is responsible.


Because message tracking typically falls outside an IT security audit, this paper foregoes that topic and focuses on the other two audit areas, which directly affect your organization’s ability to document access, changes, and actions that would be of interest during an audit.

Auditing Admin Operations

Auditors are big believers in the ability to watch the watchers. Questions around changes that IT has made are just as important as those that focus on users exercising access that IT has granted. For example, if an audit revolves around the CEO forwarding intellectual property to a competitor, a good auditor doesn’t just accept that the CEO forwarded the information. Rather, the auditor also asks who has been granted permissions to the CEO’s mailbox—and who in IT granted those permissions.

Both security and compliance initiatives are useless without auditing admin operations. Because there are no preventative controls for admins (who need the ability to do “everything” to get their job done), the need for controls that detect and deter inappropriate behavior is necessary. By putting an audit trail in place, you create accountability. After all, knowing that they’re being audited tends to encourage admins to keep their behavior in check.

When it comes to Exchange Online, a number of actions can indicate malicious activity. For example, the exporting of a mailbox doesn’t require logging on to the mailbox; IT can simply export and review the local PST. Therefore, IT logging on to an exported mailbox should trigger non-owner mailbox auditing. Another example is granting permissions: IT could assign a cohort inappropriate permissions to another user’s mailbox, and then remove those permissions after improper access is completed. Unless you have non-owner mailbox auditing enabled, this access would go completely unnoticed.

You can see why admin operations need to be included as part of your auditing strategy. Everything an admin does within Exchange Online is ultimately a PowerShell command, so Exchange audits admin activity at the PowerShell level. Each time an audited cmdlet is run, the action is logged.

To check which auditing is enabled within your organization, you can use the Get-AdminAuditConfig command, shown in the following figure.

Place specific focus on the AdminAuditLogCmdlets, AdminAuditLogExcludedCmdlets, and AdminAuditLogParameters fields, which identify whether every admin operation is audited or a subset.

Quest Insight – Age Limits

By default, admin audit data is kept for 90 days (as indicated by the AdminAuditLogAgeLimit value in the previous figure). You might want to consider extending the retention time. Organizations that perform annual audits should consider extending this value to more than 365 days (one year).

To enable auditing, you need to leverage the Set-AdminAuditLogConfig cmdlet:

Set-AdminAuditLogConfig –AdminAuditLogEnabled $true

Quest Insight – Enabling Just the Right Amount of Admin Auditing

Each organization has different auditing requirements, so auditing of admin actions isn’t always as simple as “just audit everything.” If you simply enable all admin auditing, you’ll see all the changes that Microsoft makes on the back end, which might be something you don’t care to filter through during an audit.


Because admin auditing is based on the premise that every performed action relates to running a PowerShell cmdlet, the Set-AdminAuditLogConfig cmdlet enables you to specify which cmdlets and cmdlet parameters to include or exclude. Be sure to note that auditing of commands in Exchange Online does not include read-only types of commands, such as any Get and Search commands.


You can specify individual cmdlets or use wildcard characters to denote a group of cmdlets:


Set-AdminAuditLogConfig –AdminAuditLogEnabled $true

-AdminAuditLogCmdlets * -AdminAuditLogParameters *

-AdminAuditLogExcludedCmdlets *Mailbox*, *TransportRule*


 So, how do you get this information out of Office 365?


There are two ways to extract admin auditing information from Office 365: via PowerShell or by using the Office 365 Security & Compliance portal.

Auditing via PowerShell

Using PowerShell to audit can be accomplished by using the Search-AdminAuditLog cmdlet. When you use this cmdlet with no filtering parameters, you obtain the last 1000 entries. This information shows the cmdlets and parameters that were used, who ran each action, whether the action was successful, the object affected, and more, as shown in the following figure.

The Search-AdminAuditLog cmdlet results don’t provide comprehensive detail; for example, the Caller field, which specifies which users called the cmdlet, is blank. So the cmdlet is more useful if you’re trying to get an overview of changes made rather than performing an actual audit.

You can alternatively use the New-AdminAuditLogSearch cmdlet to receive an emailed XML report of the log entries within a specified date. For example, in the following figure, you can see that an admin is adding full mailbox permissions to the user bbrooks.


Quest Insight – Filtering Cmdlet Searches

The basic cmdlets return a large amount of data that might include the behind-the-scenes management actions performed by Microsoft. So it’s important to use the cmdlet’s parameters to filter the noise of all the resulting data.


Both the Search-AdminAuditLog and New-AdminAuditLogSearch cmdlets enable you to filter by date, cmdlet used, parameters used, the user who performed the action, whether that user is external to the organization, and the objects that the action affected.


By using some of these filters, you can hone down the results to a more pertinent set of data, increasing your productivity by more quickly finding the answers you need. 

Auditing via the Office 365 Security & Compliance Portal

Those who simply aren’t “PowerShell people” and would rather use a management console can take advantage of the Audit Log Search functionality in the Office 365 Security & Compliance Portal. In the pre-created Activities, you can begin your audit by simply selecting a management action, such as the delegation of mailbox permissions in the following figure. You can use the additional filter fields to further refine the results to the few that meet your criteria.

Be aware that the Activities are a double-edged sword. You are limited to those activities (with the supported filters) and cannot generate custom search scenarios of your own. For example, you can’t search for every time someone exported a mailbox (at the time of this writing).

Results can be exported as well, for reporting and further analysis.

You will experience a few limitations should you choose to use the console. First, you’re limited to only 90 days of audit data — and there’s no way around that. In addition, although audit data is available to PowerShell cmdlets within 30 minutes, accessing the same data via the console can take up to 24 hours.

Auditing Non-Owner-Mailboxes

Auditing administrative actions helps to identify the events leading up to inappropriate activity within Exchange. But the real value is found in auditing access to the data that is stored within Exchange. The assumption with non-owner mailbox auditing is that the mailbox owner is using the mailbox appropriately. (Sure, cases of insider misuse by a mailbox owner exist, but those issues are addressed by message tracking.) So, the focus shifts to any non-owners that access a given mailbox.

In general, you should be concerned any time a non-owner views, sends email on behalf of, or deletes email in another user’s mailbox. Delegates — a part of Exchange for as long as the product has been available — are a vital part of the productivity of many users who require assistance from other employees. But because delegate access exists, and because inappropriate delegate access can be granted, auditing non-owner access to mailboxes provides an important piece of data. 

Quest Insight – Which Mailboxes Should You Audit?

Which mailboxes to audit is a valid question. Find the answer by considering these questions:


·         Is there any delegate access? If so, turn on auditing. This way, you have an audit trail of every time the delegate accesses the owner’s mailbox and what was done.

·         Does the mailbox contain sensitive data? Mailboxes that are owned by users who regularly send and receive financials, intellectual property, legal documents, and so on might be prime targets for insider activity. Even when no delegates are assigned to a mailbox that contains sensitive data, enable auditing proactively so that you have an audit trail of any and all access to the mailbox.


Unlike admin auditing, which is an organizational-wide audit setting, non-owner mailbox auditing is enabled on a per-mailbox basis. Audit log entries are retained, by default, for 90 days—a value that can be customized.

You can enable non-owner mailbox auditing at three levels, each with specific audited actions:

  • Admin. This level audits actions by admins who have not been granted delegate permissions to a mailbox.
  • Delegate. Anyone who is assigned permissions or given Send on Behalf of permissions is considered a delegate.
  • Owner. Auditing for the mailbox owner is typically disabled, as it isn’t relevant to audits. In addition, enabling owner auditing generates a great deal of information. Non-owner access is generally infrequent and limited in scope (e.g., an assistant sending out calendar invites for their boss, someone in IT finding a specific message), whereas audits of owner access encompass every email created, read, filed, deleted, and so on.






















































Enabling Non-Owner Mailbox Auditing

Like admin auditing, non-owner mailbox auditing is enabled by using PowerShell via the Set-Mailbox cmdlet. As previously mentioned, this action is accomplished on a per-mailbox basis and requires that you specify which level or levels of auditing (admin, delegate, or owner) you want to enable:


Set-Mailbox –Identity “John Smith” –AuditDelegate SendOnBehalf,FolderBind –AuditEnabled $true


AuditDelegate in this command. This parameter enables mailbox auditing, but only for delegate access and only for the specified actions. You either need to perform this command a second time to configure auditing of Administrator access, specifying which actions should be audited (as shown in the following command), or include the AuditAdmin parameters in the same execution of this cmdlet:


Set-Mailbox –Identity “John Smith” –AuditAdmin Copy,MessageBind

-AuditEnabled $true


Organizations that audit the mailbox access of every user must enable mailbox auditing for new users. This approach might require a bit more PowerShell scripting, to continuously perform a search for a user account with a recent create date and to run the previous commands against that account.

Quest Insight – Which Actions Should You Audit?

You should enable both admin and delegate access to help ensure that any (and every) instance of non-owner access is recorded. Auditing of most of the previously mentioned admin actions is automatic whenever auditing is enabled for a given mailbox, with the exception of MessageBind (which for all intents and purposes can be considered a reading of a message) and Copy. Auditing of these actions needs to be enabled separately (as explained earlier). Also note that whenever an admin is assigned Full Access to a mailbox, that admin is considered a delegate user and is audited as such.


Like admin, some delegate actions (i.e., Create, HardDelete, SendAs, SoftDelete, and Update) are also automatically audited. Therefore, you need to enable auditing for any other actions that you want to log.


Some organizations use solutions that scan mailboxes for compliance, identification of sensitive data, categorization for legal purposes, and so on. Such solutions might trigger bogus events because of their access of a given mailbox. In such situation, you can use the Set-MailboxAuditBypassAssociation cmdlet to bypass auditing for a specific, trusted account.

Now that you have enabled mailbox auditing, how do you get your audit logs out?

This process is a bit complicated, as it depends on how many mailboxes you need to audit, how much detail you want to obtain, and whether you need the raw audit data or a report format. You have a few options:

  • Synchronously via PowerShell. You can use the Search-MailboxAuditLog cmdlet to search a single mailbox’s audit log entries. The cmdlet displays search results in the Exchange Management Shell window and provides limited detail that might not meet your auditing requirements.
  • Asynchronously via PowerShell. You can use the New-MailboxAuditLogSearch cmdlet to search through the audit logs of one or more mailboxes, with the results sent to a specified email address as an XML file. If you want to pull audit data into your SIEM solution, use this option. Should your cmdlet query criteria generate too many results, then the received email simply informs you that the query was a failure. You’ll need to further hone the results to a smaller data set, potentially requiring the combination of multiple XML files to represent a complete audit of all actions. Be aware that Exchange 2016 allows only 10 searches of this type per mailbox within a 24-hour period.Exchange admin center reports. From within the Exchange admin center’s reports section (not the Office 365 Security & Compliance portal), you can run a Search for mailboxes accessed by non-owners report. However, you cannot export this data.
  • Office 365 Management Activity API. Microsoft provides a RESTful API to access audit data. This API requires some significant development, so it might not be an option for most organizations. However this is the only viable option for getting your all your audit data out of the cloud and into a compliance-ready secure archival and monitoring platform. To be compliant you have to use this API.

It can take up to 24 hours for events to show up in the unified audit log where they are stored, so you should expect some latency around audit requests. Also note that none of these options make it truly easy to obtain the information you need. Some don’t provide the necessary granularity, whereas others require that granularity if they are to be valuable. Think of each option more as another tool to access raw data than as an auditing solution designed to provide you with correlated, formatted intelligence around performed actions.

Meeting Compliance and Security Requirements

The good news is that Office 365 does capture the audit data you need. But compliance and security require more than just capture audit data. You have to protect, archive and most importantly monitor that audit data. And monitoring means correlating with other security information from your environment so that you can actually detect attacks and misuse.

So the bad news is that if there is no way you can meet enterprise compliance and security requirements with the out of box functionality of Office 365. You must either write your own application to access the Management Activity API or exploit a solution that does that for you.

Enter Quest Change Auditor. Change Auditor now integrates audit logs from Exchange Online with the rest of the activity Change Auditor collects, normalizes and monitors from all over your network. The latest version of Change Auditor implements the Management Activity API and other APIs from Office 365 to automatically collect Exchange Online mailbox and administrator audit logs. Change Auditor brings to Exchange Online the same Who, What, When and Where capability ChangeAuditor is famous for. And the cool thing is now you see what a given user like Bob is doing both in the cloud and on your internal network because ChangeAuditor already monitors

  • Active Directory
  • SharePoint
  • Windows
  • SQL Server
  • Network Attached Storage
  • Lync
  • VMware

You can’t be compliance without monitoring your environment and that fact doesn’t go away when you move to the cloud. Office 365 captures the activity required by enterprises for compliance but it’s up to you after that. Change Auditor solves this issue and puts cloud activity and on-prem events on the same pane of glass.


About Randy Franklin Smith

Randy Franklin Smith is an internationally recognized expert on the security and control of Windows and AD security. Randy publishes and wrote The Windows Server 2008 Security Log Revealed—the only book devoted to the Windows security log. Randy is the creator of LOGbinder software, which makes cryptic application logs understandable and available to log-management and SIEM solutions. As a Certified Information Systems Auditor, Randy performs security reviews for clients ranging from small, privately held firms to Fortune 500 companies, national, and international organizations. Randy is also a Microsoft Security Most Valuable Professional.


Monterey Technology Group, Inc. and Dell Software make no claim that use of this white paper will assure a successful outcome. Readers use all information within this document at their own risk.

[L1] Osterman Research, 2015

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Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
5 Indicators of Endpoint Evil
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure
Anatomy of a Hack Disrupted: How one of SIEM’s out-of-the-box rules caught an intrusion and beyond

Tracking Physical Presence with the Windows Security Log

Tue, 20 Dec 2016 10:52:13 GMT

How do you figure out when someone was actually logged onto their PC? By “logged onto” I mean, physically present and interacting with their computer. The data is there in the security log but it’s so much harder than you’d think.

First of all, while I said it’s in the security log, I didn’t say which one. The bad news it isn’t in the domain controller log. Domain controllers know when you logon but they don’t know when you logoff. This is because domain controllers just handle initial authentication to the domain and subsequent authentications to each computer on the network. These are reflected as Kerberos events for Ticket-Granting Tickets and Service Tickets respectively. But domain controllers are not contacted and have no knowledge when you logoff – at all. In fact, look at the evens under Account Logon audit policy subcategory; these are the key domain controller events generated when a user logs on with a domain account. As you can see there is no logoff event. That event it only logged by the Logoff subcategory which and really, the whole concept of a discreet session with a logon and logoff has disappeared. You may remain “logged on” to your PC for days if not weeks. So the real question is not “Was Bob logged in?”, it’s more about “Was Bob physically present, interacting with the PC?”. To answer this you have to look at much more than simple logon/logoff events which may be separated by long periods of time during which Bob is anywhere but at his computer.

Physical presence auditing requires looking at all the events between logon and logoff such as when the console locks, the computer sleeps and screen saver events.

Logon session auditing isn’t just a curious technical challenge. At every tradeshow and conference I go to, people come to me with various security and compliance requirements where they need this capability. In fact one of the cases where I’ve been consulted as an expert witness centered around the interpretation of logon events for session auditing.

The absolute only way to track actual logon sessions is to go to the workstation’s security log. There you need to enable 3 audit subcategories:

  1. Logon
  2. Logoff
  3. Other Logon/Logoff

Together, these 3 categories log 9 different events relevant to our topic

  • 4624 - An account was successfully logged on
  • 4634 - An account was logged off
  • 4647 - User initiated logoff
  • 4800 - The workstation was locked
  • 4801 - The workstation was unlocked
  • 4802 - The screen saver was invoked
  • 4803 - The screen saver was dismissed

But how do you correlate these events because that’s what it’s all about when it comes to figuring out logon sessions. It is by no means a cakewalk. Matching these events is like sequencing DNA but the information is there. The best thing to do is experiment for yourself. Enable the 3 audit policies above and then logon, wait for your screen saver to kick in, dismiss the screen saver, lock the console as though you are walking away and then unlock it. Allow the computer to sleep. Wake it back up.

As you can see there is some overlap among the above events. What you have to do is between a given logon/logoff event pair (linked by Logon ID), identity the time periods within that session where the user was not present as a result of

  • Sleep (that of the computer)
  • Hibernation
  • Screen saver
  • Console locked

And count any session as ending if you see

  • Event ID 4647 for that session’s Logon ID (User initiated logoff)
  • Event ID 4354 for that session’s Logon ID (Logoff)
  • Event ID 4608 – System startup

As you can see, the information is there. But you have to collect it and that is a challenge for most organization because of the sheer number of workstations. SIEM solutions like EventTracker automate this for you whether by remote event collection which can be practical in some cases or with the more feasible end-point agent.

This article by Randy Smith was originally published by EventTracker

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Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
Understanding the Difference between “Account Logon” and “Logon/Logoff” Events in the Windows Security Log
5 Indicators of Endpoint Evil
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure

How to Audit Privileged Operations and Mailbox Access in Office 365 Exchange Online

Fri, 02 Dec 2016 12:40:20 GMT

Moving Exchange to the Office 365 cloud eliminates a lot of work but it doesn’t eliminate your compliance responsibilities or security requirements. To be compliant and to detect information grabs and data theft you need 2 critical feeds of activity from Exchange Online:

  1. Non-owner mailbox access – especially “high value” mailboxes like executives
  2. Privileged user operations

Exchange Online provides the ability to monitor both. And if you are familiar with Exchange on-premise you will find a degree of shared functionality – at least on the surface.

For instance, the configuration of mailbox audit policy and of the admin audit log use the same 2 PowerShell commands as Exchange on-premise

  • Set-Mailbox and all the “-Audit…” parameters
  • Set-AdminAuditLogConfig

But as with Exchange on-premise, getting the audit data out of Exchange Online is nowhere as easy. Especially with regard to mailbox auditing. The Search-MailboxAuditLog command that runs synchronously has restrictions on the amount of detail that eliminates it from consideration. The asynchronous New-MailboxAuditLogSearch command has restrictions (also found in Exchange 2016) that silently limits you to 10 search requests in any 12-hour period. And those search requests have caps on the amount of results and can take many hours to be fulfilled.

On the interactive side, Office 365 provides an Audit and Compliance portal that allows you to perform ad hoc searches against the “unified audit log” which includes Exchange Online audit events. However this portal is really only appropriate for fairly casual investigations into recent activity. You are limited to certain pre-conceived search scenarios of which viewing content of mailboxes is conspicuously absent. Perhaps most importantly, Office 365 only keeps audit data for 90 days.

So how does an enterprise fulfill their compliance requirements? Microsoft is certainly not unaware of compliance and the fact that they can’t go to market without giving customers some options. Right now there is just one option: the Management Activity API. This RESTful service does provide an enterprise-grade ability to get all your audit data out of Office 365. But it requires custom programming and at that point you’ve only gotten the audit data out of the cloud in XML format. What do you do with it then? Never mind the rest of the compliance story such as reporting, alerting, archiving and so on. And if I was a cyber security officer I’d want to be able to correlate that activity in the cloud with everything else going on in my network.

That’s where Quest Change Auditor comes in. The folks at Quest have done the heavy lifting to integrate audit logs from Exchange Online with the rest of the activity they collect, normalize and monitor from all over your network. The latest version of Change Auditor implements the Management Activity API and other APIs from Office 365 to automatically collect Exchange Online mailbox and administrator audit logs. Change Auditor brings to Exchange Online the same Who, What, When, Where, and what Workstation capability ChangeAuditor is famous for. And the cool thing is now you see what a given user like Bob is doing both in the cloud and on your internal network because ChangeAuditor already monitors

  • Active Directory
  • Azure AD
  • Windows
  • SharePoint
  • SQL Server
  • Network Attached Storage - EMC, NetApp, Dell FluidFS
  • Skype for Business/Lync
  • VMware

You can’t be secure and compliant without monitoring your environment and that fact doesn’t go away when you move to the cloud. Office 365 captures the activity required by enterprises for compliance but it’s up to you after that. Change Auditor simplifies the audit process by tracking, auditing, reporting and alerting on Microsoft® Exchange Server and Office 365 Exchange Online configuration and permission changes in real time, and solves this issue by combining cloud activity and on-premise activity on the same pane of glass. To ensure Exchange and Office 365 compliance, you can automatically generate intelligent, in-depth reports, protecting you against policy violations and avoiding the risks and errors associated with day-to-day modifications. And, for fast troubleshooting, you always get the original and current values.

To learn more information on Change Auditor please visit:

Or for a Trial Download of Change Auditor for Exchange and Exchange Online:

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Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
5 Indicators of Endpoint Evil
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure
Anatomy of a Hack Disrupted: How one of SIEM’s out-of-the-box rules caught an intrusion and beyond

How to control and detect users logging onto unauthorized computers

Fri, 11 Nov 2016 11:08:40 GMT

indows gives you several ways to control which computers a given account can logon to. Leveraging these features is a critical way to defend against persistent attackers. By limiting accounts to appropriate computers you can

  • Enforce written policies based on best practice
  • Slow down or stop lateral movement by attackers
  • Protect against pass-the-hash and related credential harvesting attacks

The first place to start using mitigation technique is with privileged accounts. And the easiest way to restrict accounts to specified computers is with the allow and deny logon rights. In Group Policy under User Rights you will find an allow and deny right for each of Windows’ 5 types of logon sessions

  • Local logon (i.e. interactive logon at the console)
  • Network logon (e.g. accessing remote computer’s file system via shared folder)
  • Remote Desktop (i.e. Terminal Services)
  • Service (when a service is started in the background it’s service account is logged on in this type of session)
  • Batch (i.e. Scheduled Task)

Of course if an account has both “Logon locally” and “Deny logon locally” the deny right will take precedence. By careful architecture of OUs, group policy objects and user groups you can assign these rights to the desired combinations of computers and users.

But because of the indirect nature of group policy and the many objects involved it can be complicated to configure the rights correctly. It’s easy to leave gaps in your controls or inadvertently prevent appropriate logon scenarios.

In Windows Server 2012 R2 Microsoft introduced Authentication Policy Silos. Whereas logon rights are enforced at the member computer level, silos are enforced centrally by the domain controller. Basically you create an Authentication Policy Silo container and assign the desired user accounts and computers to that silo. Now those user accounts can only be used for logging on to computers in that silo. Domain controllers only enforce silo restrictions when processing Kerberos authentication requests – not NTLM. To prevent users accounts from bypassing silo restrictions by authenticating via NTLM silo’d accounts must also be members of the new Protected Users group. Membership in Protected Users triggers a number of different controls designed to prevent pass-the-hash and related credential attacks – including disabling NTLM for member accounts.

For what it’s worth Active Directory has one other way to configure logon restrictions and that’s with the Logon Workstations setting on domain user accounts. However, this setting only applies to interactive logons and offers no control over the other logon session types.

Detecting Logon Violation Attempts

You can monitor failed attempts to violate both types of logon restrictions. When you attempt to logon but fail because you have not been granted or are explicitly denied a given logon right here’s what to expect in the security log.

Which Security Log

Event ID


Local computer being attempted for logon


Logon Failure

Failure reason: The user has not been granted the requested logon type at this machine.

Status: 0xC000015B

Domain Controller


Successful Kerberos TGT Request

Note that this is a successful event.  To the domain controller this was as a successful authentication. 


As you can see there is no centralized audit log record of logon failures due to logon right restrictions. You must collector and monitor the logs of each computer on the network.

On the other hand, here are the event logged when you attempt to violate an authentication silo boundary.

Which Security Log

Event ID


Local computer being attempted for logon


Logon Failure

Failure reason: User not allowed to logon at this computer

Status: 0xC000006E

Domain Controller

4820 Failure

A Kerberos Ticket-granting-ticket (TGT) was denied because the device does not meet the access control restrictions. 

The silo is identified

4768 Failed Kerberos TGT Request

Result Code: 0xC

An obvious advantage of Authentication Silos is the central control and monitoring. Just monitor your domain controllers for event ID 4820 and you’ll know about all attempts to bypass your logon controls across the entire network. Additionally, event ID 4820 reports the name of the silo which makes policy identification instant.

Restricting privileged accounts is a key control in mitigating the risk of pass-the-hash and fighting modern attackers. Whether you enforce logon restrictions with user rights on local systems or centrally with Authentication Silos make sure you don’t just use a “fire and forget” approach in which you configure but neglect monitoring these valuable controls. You need to know when an admin is attempting to circumvent controls or when an attacker is attempting to move laterally across your network using harvested credentials.

"This article by Randy Smith was originally published by EventTracker"

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5 Indicators of Endpoint Evil
Auditing Privileged Operations and Mailbox Access in Office 365 Exchange Online
Live with Dell at RSA 2015
Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure

Severing the Horizontal Kill Chain: The Role of Micro-Segmentation in Your Virtualization Infrastructure

Wed, 12 Oct 2016 12:58:16 GMT

Keeping malware off and external threat actors out of your network is definitely important. But equally important is considering how to protect your network if a threat does find its way in.

One of the first goals of any external threat actor after it accesses your organization’s network—whether via spear phishing, social engineering, or some other means of inserting malware onto and compromising a machine—is to spread out within your network and to access and infect as many machines as possible. This strategy is designed to maintain malicious access, should any individual instance of malware infection be discovered. Other attack methods can involve far more advanced and coordinated attacks in which multiple machines are compromised and installed malware lies dormant until triggered remotely.

This reality requires some means to minimize the ability of a threat to spread within your network. In a physical networking environment, isolating malware is difficult without the presence of agent-based software on every endpoint. But a software-defined data center (SDDC) can take advantage of new advances in network virtualization to identify and isolate the threat, integrating best-of-breed security vendor solutions.

In this whitepaper, we’ll discuss network virtualization and micro-segmentation’s role in thwarting attacks. We’ll look at how micro-segmentation is implemented within a virtual infrastructure. And we’ll see how integrating third-party security solutions can provide the highest level of security and protection.

Network Virtualization and the SDDC

Three typical components are found in a data center: compute, storage, and networking. Virtualized compute has been a reality for more than a decade, with virtual storage present for a majority of that time as well. But only with the more recent availability of network virtualization—also known as software-defined networking (SDN)—has a true SDDC come to fruition. Network virtualization brings to the network the same programmatic creation, deletion, snapshotting, and restoration functionality that is employed at a virtual machine (VM) level. With these capabilities, network virtualization goes well beyond just another logical network and completes the vision of the SDDC by making the network software-defined as well.

By implementing network virtualization, your SDDC gains these benefits:

  • Simplification of your physical network. Traditionally, the physical network is designed around bandwidth needs, geographic constraints (e.g., buildings, multiple floors, independent locations), and security. By virtualizing your network, you can eliminate the impact of security concerns on the physical design, enabling you to focus solely on bandwidth and geography issues. It’s important to note that to implement SDN, you are not required to reconfigure any part of your physical network; rather, taking advantage of SDN as you build a data center means that you can dramatically simplify the physical network topology.
  • Agility and speed.Because network services in Layers 2 through 7 have been virtualized, the ability to create a customized virtual network can be achieved in seconds. This option includes benefits for those wanting to isolate a developer network or host a multi-tenant infrastructure.
  • Automation.Through an API that conforms to Representation State Transfer (a RESTful API) and automation tools, the ability to set up and configure a virtual environment can now include networking in addition to compute, storage, network, and security.
  • Security.With the agility to build networks quickly comes the ability to implement dynamic security models. This approach includes securing traffic between an application and the virtual client that accesses the application, spinning up a demilitarized zone (DMZ) anywhere, and (as this paper will discuss later) micro-segmenting the network to isolate applications, virtual clients, and virtual servers to sever the horizontal spread of malware throughout a network.

So where does this network virtualization exist?

Network virtualization lives within your hypervisor, acting as an abstraction layer between the physical network and your VMs, applications, and data.

A great example of a network virtualization solution is the VMware NSX platform, part of the VMware vision for the SDDC. NSX virtualizes the network and its physical components, allowing fast, robust configuration and security of a software-defined network.


Creating, maintaining, securing, and managing a virtualized network is no simple feat. To help you accomplish all these tasks, NSX is made up of a number of infrastructure components:

  • NSX Manager. Implemented as a virtual appliance, NSX Manager automates the deployment and management of logical networks.
  • NSX controller. Implemented as a cluster for redundancy, the controller is responsible for managing the hypervisor switching and routing modules.
  • Hypervisor kernel modules. These add-on modules provide services that include distributed routing, the distributed firewall (DFW), and VXLAN-to-VLAN bridging.
  • NSX Edge. This component provides seamless integration with the physical network, processing communication with the external network.

Put together, these components provide the management and security foundation to virtualize networking objects that are normally found in a physical environment, including logical switches, routers, firewalls, DHCP servers, and so on, as shown in Figure 1

Figure 1: NSX virtualizes traditional physical networking components, making the network itself software-defined.

So, how can the NSX virtualization platform help improve security and stop the horizontal kill chain?

Implementing Micro-Segmentation with NSX

One of the greatest benefits of network virtualization is the ability to divide a network into smaller virtual zones, called micro-segments. These micro-segments help to isolate services, applications, and VMs, providing protection by making security more dynamic and multilayered.

To create micro-segmentation, NSX uses a DFW residing on each VM’s virtual network card (vNIC). NSX manages the DFWs centrally to ensure consistent and up-to-date firewall rules.

DFW Rules

DFW rules are much like any rule that you might see on a given firewall. These rules define which traffic is allowed through the firewall by defining source and destination IP addresses, the service that is responsible for the traffic (defined as port-protocol combinations), and the action to be taken (allow/deny) within each rule.

When multiple DFW rules exist, the rule sequence doesn’t come into play—with the exception of deny rules, which take precedence. This scenario further simplifies rule creation and management.

In addition, each rule can either be applied to the default value of every DFW or be applied granularly within the NSX environment to specific VMware vSphere objects, including clusters, datacenters, vNetwork Distributed Switch (vDS) distributed port groups, logical switches, Edges, host systems, security groups, VMs, or vNICs. Keep in mind that even though a rule is applied to a specific DFW, the source and destination parameters within the rule must match the inspected traffic for the rule action to occur.

Even though DFW rules are useful, applying them to VMs doesn’t seem entirely sensible, does it?

Applying Practical Granularity via Security Tags

If you’re thinking about the practical application of this technology, you might be concerned that the granularity that a DFW rule provides doesn’t align with the way you want to manage server security. Think about it: You want the ability to apply a rule quickly and easily to all your database servers, every VM on a particular host, or every client VM that interacts with protected data (e.g., credit cards, patient information), right?

NSX provides the ability to apply DFW rules in a more user-friendly manner, by using a few pieces of technology within the NSX framework. The first of these pieces is security tags. Individual VMs can be assigned multiple security tags. Because tags are assigned to the VM, the tag remains part of the definition even if the VM is moved.

Tags are used within security policies, the second part of this “practical application” equation. In their most basic sense, security policies define how you want to protect a given VM. Each security policy contains rules that control DFWs, as well as guest-OS and network-introspection controls that integrate with partner solutions to provide additional layers of monitoring and protection. Security policies also have their own weight and inheritance methods to determine which policies are applied first.

So, how do you take advantage of tags and security policies?

The Secret Sauce: Security Groups

What makes NSX micro-segmentation so robust is the use of security groups. Security groups can have multiple security policies assigned to them and define which VMs should have those security policies (and therefore, the DFW rules) applied to them. Security groups employ both static and dynamic memberships to ensure that the most up-to-date policies are applied. This approach is critical, as DFW rules might need to be created and applied in response to a current attack.

As Figure 2 shows, security policies define how protection should be implemented, whereas the security group defines what should be protected.

Figure 2: Security policies and security groups work together to dynamically protect the vSphere environment.

Security group membership is defined using two inclusion sets and one exclusion set:

  • Static inclusions. A static inclusion set includes static entries of VMs, clusters, logical switches, networks, vAPPs, datacenters, IP sets, Active Directory groups, MAC sets, security tags, vNICs, resource pools, distributed virtual switch port groups, and other security groups.
  • Dynamic inclusions. A dynamic inclusion set includes matching computer names, OS names, VM names, security tags, and entity values, using comparative criteria statements such as “VM Name Contains ‘Oracle’”. Multiple sets of criteria are supported within a single security group.
  • Static exclusions. These exclusions are processed after NSX tallies the final list of inclusions, ensuring that exclusions are never overridden.

Because security group members are both statically and dynamically defined, you can use membership to reference common functionality of servers (e.g., every VM running Oracle), location, data-classification levels, environment type (e.g., production versus development), department, and—most important when addressing the horizontal kill chain—current security state.

Dynamic inclusions make micro-segmentation truly useful in this scenario. Third-party vendors can tag a VM based on, say, an antivirus scan or an intrusion detection. A DFW rule (via a security policy) immediately takes effect to isolate the impacted VM and protect the rest of the network from the spread of malware.

Severing the Horizontal Kill Chain … and Beyond

With one of the goals of micro-segmentation being to stop the horizontal kill chain, you must embrace all three parts of the puzzle and configure DFW rules to isolate server, application, and client traffic, thus minimizing the risk of intrusion or infection in the first place. But it’s the addition of security policies and the dynamic inclusions within security groups that make DFW rules a granular, responsive tool.

By utilizing all three pieces—along with integrated third-party solutions that monitor and scan for intrusions, breaches, inappropriate access, malware, viruses, and more as the basis for security group membership—the simple DFW becomes the foundation for a powerful and flexible way of halting inappropriate and potentially malicious east-west traffic between VMs.

Getting to Zero Trust

Micro-segmentation can also be used to implement a zero-trust security model within your virtual network, in which no entity—users, devices, applications, or any other—has a default level of trust. This is based on the “never trust, always verify” security approach first proposed by Forrester Research.

Applying this approach within the context of micro-segmentation creates as secure an environment as possible. To do so, you’ll need to follow these steps:

  • Baseline. Start with an approved set of allow rules for a given set of traffic between VMs and a default rule that Allows bus also Logs.
  • Analyze. Review the traffic that the existing allow rules are not catching.
  • Secure. Add more rules, taking advantage of more than just simple IP addresses.
  • Repeat. Continue to analyze and add rules; the amount of traffic in the log decreases in response.
  • Deny. Add temporary deny rules and, after you’re certain that all appropriate traffic is accounted for in your allow rules, add a final default rule to block all remaining traffic.

Micro-segmentation doesn’t get your organization all the way to zero trust. However, it does put in place a least privilege environment that aligns with the foundational goal of zero trust by limiting which VMs and applications can traverse a given virtualized network path.

Beyond Micro-Segmentation with Symantec

NSX is much more than micro-segmentation; it’s an extensible framework that allows security vendors like Symantec to leverage their security services, while extending the ability to protect and respond.

Without network virtualization (and all the capabilities it brings), malware on a given VM would certainly be detected, quarantined, and removed by AV at an OS level, with perhaps an alert sent. But with Guest and Network introspection rules (as part of an NSX Security policy), a vendor like Symantec can do some amazingly powerful and proactive protection of the network.

Symantec’s Data Center Security Server leverages VMware’s NSX platform to merge together anti-virus protection, insight reputation, and network-based threat detection and protection, providing a layered approach to comprehensively address a variety of attack vectors.

To protect against malware, Symantec utilizes a number of policies – some of their own, and some within NSX) to establish how intrusions are detected and responded to, as shown in Figure 3

Figure 3: Data Center Security Server controls the process of detecting, isolating, and eliminating threats via policies.

Protection starts with an NSX traffic shaping policy, to steer network traffic to a Symantec virtual appliance running on the same ESX host to facilitate the inspection of packets for malware. This can be accomplished for both east-west (server-server) and north-south (client-server) traffic. To optimize throughput of steered traffic, Symantec uses specific signatures tailored to certain workloads (for example, an Exchange server – the signature would contain traffic such as pop, smtp, imap, etc.). Should suspect traffic be found, a dynamic inclusion within a Security Group is triggered via a tag, causing more restrictive predefined Security Policies to activate and quarantine the system. Once malware is deleted from the VM in question, the tag is removed, causing it to be allowed back on the environment.

Traditional malware scans can also be used to establish tags and dynamic Security Group inclusions using Symantec’s agentless architecture. To optimize this process, all machines on a given ESX host are initially scanned, creating cached hashes of all files across all VMs on that host. As files are access, the hash is sent to the virtual appliance to be compared with the scan hash to speed up the AV scan process while maintaining the same level of protection as agent-based AV.

Placing the adaptable Data Center Security Server security architecture on top of the already flexible NSX platform empowers organizations to both detect intrusions (via file integrity scans) and prevent them (via enforced security policies, restriction of traffic flow, and limited app connectivity).

Achieving Better Security through Micro-Segmentation

Even as organizations move to a true SDDC, the reality of external threats grows, requiring those same organizations to implement new technologies and security methods to minimize the risk. Advances in network virtualization have made the implementation, maintenance, and security of virtual environments easier, faster, and more responsive to current business needs.

Micro-segmentation, as part of an overall network virtualization implementation, provides a means to dynamically manage the security of VMs, based on a variety of offerings and usage factors. But micro-segmentation will take your security only so far; in and of itself, it is only a means to establish a secure configuration.

Truly addressing the horizontal kill chain of attacks requires the addition of third-party security solutions to provide context around the proper micro-segmentation configuration. These solutions first identify when an attack occurs, use integration with network virtualization to isolate the threat, and allow the entire environment to remain secure while the threat is neutralized.


Since its inception in 1982, Symantec has grown into a Fortune 500 company through a combination of internal development, strategic acquisition and partnering with industry leaders. At every step in the company’s growth we have expanded both our technological expertise and our understanding of customer needs. Our ability to successfully integrate internally developed with technologies we acquire has kept Symantec at the front of its industry and enabled us to provide best-of-breed solutions for millions of corporate and individual customers in more than 48 countries. It is what has earned the company almost every major technology award and top-tier rankings from industry analysts.


Randy Franklin Smith is an internationally recognized expert on the security and control of Windows and AD security. Randy publishes and wrote The Windows Server 2008 Security Log Revealed—the only book devoted to the Windows security log. Randy is the creator of LOGbinder software, which makes cryptic application logs understandable and available to log-management and SIEM solutions. As a Certified Information Systems Auditor, Randy performs security reviews for clients ranging from small, privately held firms to Fortune 500 companies, national, and international organizations. Randy is also a Microsoft Security Most Valuable Professional.


Monterey Technology Group, Inc. and Symantec make no claim that use of this white paper will assure a successful outcome. Readers use all information within this document at their own risk. Ultimate Windows Security is a division of Monterey Technology Group, Inc. ©2006-2016 Monterey Technology Group, Inc. All rights reserved.

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