The Evolution of AD RMS to Azure Information Protection – Part 7 – Deep Dive into cross Azure AD tenant consumption

The Evolution of AD RMS to Azure Information Protection – Part 7 – Deep Dive into cross Azure AD tenant consumption

Each time I think I’ve covered what I want to for Azure Information Protection (AIP), I think of another fun topic to explore.  In this post I’m going to look at how AIP can be used to share information with users that exist outside your tenant.  We’ll be looking at the scenario where an organization has a requirement to share protected content with another organization that has an Office 365 tenant.

Due to my requirements to test access from a second tenant, I’m going to supplement the lab I’ve been using.  I’m adding to the mix my second Azure AD tenant at journeyofthegeek.com.  Specific configuration items to note are as follows:

  • The tenant’s custom domain of journeyofthegeek.com is an Azure AD (AAD)-managed domain.
  • I’ve created two users for testing.  The first is named Homer Simpson (homer.simpson@journeyofthegeek.com) and the second is Bart Simpson (bart.simpson@journeyofthegeek.com).
  • Each user have been licensed with Office 365 E3 and Enterprise Mobility + Security E5 licenses.
  • Three mail-enabled security groups have been created.  The groups are named The Simpsons (thesimpsons@journeyofthegeek.com), JOG Accounting (jogaccounting@journeyofthegeek.com), and JOG IT (jogit@journeyofthegeek.com).
  • Homer Simpson is a member of The Simpsons and JOG Accounting while Bart Simpson is a member of The Simpsons and JOG IT.
  • Two additional AIP policies have been created in addition to the Global policy.  One policy is named JOG IT and one is named JOG Accounting.
  • The Global AIP policy has an additional label created named PII that enforces protection.  The label is configured to detect at least one occurrence of a US social security number.  The document is protection policy allows only members of the The Simpsons group to the role of viewer.
  • The JOG Accounting and JOG IT AIP policies have both been configured with an additional label of either JOG Accounting or JOG IT.  A sublabel for each label has also been created which enforces protection and restricts members of the relevant departmental group to the role of viewer.
  • I’ve repurposed the GIWCLIENT2 machine and have created two local users named Bart Simpson and Homer Simpson.

Once I had my tenant configuration up and running, I initialized Homer Simpson on GIWCLIENT2.  I already had the AIP Client installed on the machine, so upon first opening Microsoft Word, the same bootstrapping process I described in my previous post occurred for the MSIPC client and the AIP client.  Notice that the document has had the Confidential \ All Employees label applied to the document automatically as was configured in the Global AIP policy.  Notice also the Custom Permissions option which is presented to the user because I’ve enabled the appropriate setting in the relevant AIP policies.

7aip1.png

I’ll be restricting access to the document by allowing users in the geekintheweeds.com organization to hold the Viewer role.  The geekintheweeds.com domain is associated with my other Azure AD tenant that I have been using for the lab for this series of posts.  First thing I do is change the classification label from Confidential \ All Employees to General.  That label is a default label provided by Microsoft which has an RMS Template applied that restricts viewers to users within the tenant.

One interesting finding I discovered through my testing is that the user can go through the process of protecting with custom permissions using a label that has a pre-configured template and the AIP client won’t throw any errors, but the custom permissions won’t be applied.  This makes perfect sense from a security perspective, but it would be nice to inform the user with an error or warning.  I can see this creating unnecessary help desk calls with how it’s configured now.

When I attempt to change my classification label to General, I receive a prompt requiring me to justify the drop in classification.  This is yet another setting I’ve configured in my Global AIP policy.  This seems to be a standard feature in most data classification solutions from what I’ve observed in another major vendor.

7aip2.png

After successfully classifying the document with the General label protection is removed from the document. At this point I can apply my custom permissions as seen below.

7aip3.png

I repeated the process for another protected doc named jog_protected_for_Ash_Williams.docx with permissions restricted to ash.williams@geekintheweeds.com.  I packaged both files into an email and sent them to Ash Williams who is a user in the Geek In The Weeds tenant.  Keep in mind the users in the Geek In The Weeds tenant are synchronized from a Windows Active Directory domain and use federated authentication.

After opening Outlook the message email from Homer Simpson arrives in Ash William’s inbox.   At this point I copied the files to my desktop, closed Outlook, opened Microsoft Word and used the “Reset Settings” options of the AIP client, and signed out of my Office profile.

7aip4

At this point I started Fiddler and opened one of the Microsoft Word document. Microsoft Word pops-up a login prompt where I type in my username of ash.williams@geekintheweeds.com and I’m authenticated to Office 365 through the standard federated authentication flow. The document then pops open.

7aip5.png

Examining the Fiddler capture we see a lot of chatter. Let’s take a look at this in chunks, first addressing the initial calls to the AIP endpoint.

7aip6

If you have previous experience with the MSIPC client in the AD RMS world you’ll recall that it makes its calls in the following order:

  1. Searches HKLM registry hive
  2. Searches HKCU registry hive
  3. Web request to the RMS licensing pipeline for the RMS endpoint listed in the metadata attached to the protected document

In my previous deep dives into AD RMS we observed this behavior in action.  In the AIP world, it looks like the MSIPC client performs similarly.  The endpoint we see it first contacting is the Journey of the Geek which starts with 196d8e.

The client first sends an unauthenticated HTTP GET to the Server endpoint in the licensing pipeline. The response the server gives is a list of available SOAP functions which include GetLicensorCertificate and GetServerInfo as seen below.

7aip8.png

The client follows up the actions below:

  1. Now that the client knows the endpoint supports the GetServerInfo SOAP function, it sends an unauthenticated HTTP POST which includes the SOAP action of GetServerInfo.  The AIP endpoint returns a response which includes the capabilities of the AIP service and the relevant endpoints for certification and the like.
  2. It uses that information received from the previous request to send an unauthenticated HTTP POST which includes the SOAP action of ServiceDiscoveryForUser.  The service returns a 401.

At this point the client needs to obtain a bearer access token to proceed.  This process is actually pretty interesting and warrants a closer look.

7aip9

Let’s step through the conversation:

  1. We first see a connection opened to odc.officeapps.live.com and an unauthenticated HTTP GET to the /odc/emailhrd/getfederationprovider URI with query strings of geekintheweeds.com.  This is a home realm discovery process trying to the provider for the user’s email domain.

    My guess is this is MSAL In action and is allowing support for multiple IdPs like Azure AD, Microsoft Live, Google, and the like.  I’ll be testing this theory in a later post where I test consumption by a Google user.

    The server responds with a number of headers containing information about the token endpoints for Azure AD (since this is domain associated with an Azure AD tenant.)

    7aip10.png

  2. A connection is then opened to odc.officeapps.live.com and an unauthenticated HTTP GET to the /odc/emailhrd/getidp with the email address for my user ash.williams@geekintheweeds.com. The response is interesting in that I would have thought it would return the user’s tenant ID. Instead it returns a JSON response of OrgId.

    7aip11.png

    Since I’m a nosey geek, I decided to unlock the session for editing.  First I put in the email address associated with a Microsoft Live.  Instead of OrgId it returned MSA which indicates it detects it as being a Microsoft Live account.  I then plugged in a @gmail.com account to see if I would get back Google but instead I received back neither.  OrgId seems to indicate that it’s an account associated with an Azure AD tenant.  Maybe it would perform alternative steps depending on whether it’s MSA or Azure AD in future steps?  No clue.

  3. Next, a connection is made to oauth2 endpoint for the journeyofthegeek.com tenant. The machine makes an unathenticated requests an access token for the https://api.aadrm.com/ in order to impersonate Ash Williams. Now if you know your OAuth, you know the user needs to authenticate and approve the access before the access token can be issued. The response from the oauth2 endpoint is a redirect over to the AD FS server so the user can authenticate.

    7aip12.png

  4. After the user successfully authenticates, he is returned a security token and redirected back to login.microsoftonline.com where the assertion is posted and the user is successfully authenticated and is returned an authorization code.

    7aip13.png

  5. The machine then takes that authorization code and posts it to the oauth2 endpoint for my journeyofthegeek.com tenant. It receives back an Open ID Connect id token for ash.williams, a bearer access token, and a refresh token for the Azure RMS API.

    7aip14.png

    Decoding the bearer access token we come across some interesting information.  We can see the audience for the token is the Azure RMS API, the issuer of the token is the tenant id associated with journeyofthegeek.com (interesting right?), and the identity provider for the user is the tenant id for geekintheweeds.com.

    7aip15.png

  6. After the access token is obtained the machine closes out the session with login.microsoftonline.com and of course dumps a bunch of telemetry (can you see the trend here?).

    7aip16.png

  7. A connection is again made to odc.officeapps.live.com and the /odc/emailhrd/getfederationprovider URI with an unauthenticated request which includes a query string of geekintheweeds.com. The same process as before takes place.

Exhausted yet?  Well it’s about to get even more interesting if you’re an RMS nerd like myself.

7aip17.png

Let’s talk through the sessions above.

  1. A connection is opened to the geekintheweeds.com /wmcs/certification/server.asmx AIP endpoint with an unauthenticated HTTP POST and a SOAP action of GetServerInfo.  The endpoint responds as we’ve observed previously with information about the AIP instance including features and endpoints for the various pipelines.
  2. A connection is opened to the geekintheweeds.com /wmcs/oauth2/servicediscovery/servicediscovery.asmx AIP endpoint with an unauthenticated HTTP POST and a SOAP action of ServiceDiscoveryForUser.  We know from the bootstrapping process I covered in my last post, that this action requires authentication, so we see the service return a 401.
  3. A connection is opened to the geekintheweeds.com /wmcs/oauth2/certification/server.asmx AIP endpoint with an unauthenticated HTTP POST and SOAP action of GetLicensorCertificate.  The SLC and its chain is returned to the machine in the response.
  4. A connection is opened to the geekintheweeds.com /wmcs/oauth2/certification/certification.asmx AIP endpoint with an unauthenticated HTTP POST and SOAP action of Certify.  Again, we remember from my last post that this requires authentication, so the service again responds with a 401.

What we learned from the above is the bearer access token the client obtained earlier isn’t attended for the geekintheweeds.com AIP endpoint because we never see it used.  So how will the machine complete its bootstrap process?  Well let’s see.

  1. A connection is opened to the journeyofthegeek.com /wmcs/oauth2/servicediscovery/servicediscovery.asmx AIP endpoint with an unauthenticated HTTP POST and SOAP action of ServiceDiscoveryForUser.  The service returns a 401 after which the client makes the same connection and HTTP POST again, but this time including its bearer access token it retrieved earlier.  The service provides a response with the relevant pipelines for the journeyofthegeek.com AIP instance.
  2. A connection is opened to the journeyofthegeek.com /wmcs/oauth2/certification/server.asmx AIP endpoint with an authenticated (bearer access token) HTTP POST and SOAP action of GetLicensorCertificate.  The service returns the SLC and its chain.
  3. A connection is opened to the journeyofthegeek.com /wmcs/oauth2/certification/certification.asmx AIP endpoint with an authenticated (bearer access token) HTTP POST and SOAP action of Certify.  The service returns a RAC for the ash.williams@geekintheweeds.com along with relevant SLC and chain.  Wait what?  A RAC from the journeyofthegeek.com AIP instance for a user in geekintheweeds.com?   Well folks this is supported through RMS’s support for federation.  Since all Azure AD’s in a given offering (commercial, gov, etc) come pre-federated, this use case is supported.
  4. A connection is opened to the journeyofthegeek.com /wmcs/licensing/server.asmx AIP endpoint with an uauthenticated HTTP POST and SOAP action of GetServerInfo.  We’ve covered this enough to know what’s returned.
  5. A connection is opened to the journeyofthegeek.com /wmcs/licensing/publish.asmx AIP endpoint with an authenticated (bearer access token) HTTP POST and SOAP action of GetClientLicensorandUserCertificates.  The server returns the CLC and EUL to the user.

After this our protected document opens in Microsoft Word.

7aip18.png

Pretty neat right? Smart move by Microsoft to take advantage and build upon of the federated capabilities built into AD RMS. This is another example showing just how far ahead of their game the product team for AD RMS was. Heck, there are SaaS vendors that still don’t support SAML, let alone on-premises products from 10 years ago.

In the next few posts (can you tell I find RMS fascinating yet?) of this series I’ll explore how Microsoft has integrated AIP into OneDrive, SharePoint Online, and Exchange Online.

Have a great week!

The Evolution of AD RMS to Azure Information Protection – Part 6 – Deep Dive into Client Bootstrapping

The Evolution of AD RMS to Azure Information Protection – Part 6 – Deep Dive into Client Bootstrapping

Today I’m back with more Azure Information Protection (AIP) goodness.  Over the past five posts I’ve covered the use cases, concepts and migration paths.  Today I’m going to get really nerdy and take a look behind the curtains at how the MSIPC client shipped with Office 2016 interacts with AIP .  I’ll be examining the MSIPC client log and reviewing procmon and Fiddler captures.  If the thought of examining log files and SOAP calls excites you, this is a post for you.  Make sure to take a read through my previous posts to ensure you understand my lab infrastructure and configuration as well as key AIP concepts.

Baselining the Client

Like any good engineer, I wanted to baseline my machine to ensure the MSIPC client was functioning correctly.  Recall that my clients are migrating from an on-premises AD RMS implementation to AIP.  I haven’t completed my removal of AD RMS so the service connection point for on-premises AD RMS is still there and the migration scripts Microsoft provides are still in use.  Let’s take a look at the registry entries that are set via the Migrate-Client and Migrate-User script.  In my last post I covered the purpose of the two scripts.  For the purposes of this post, I’m going to keep it brief and only cover registry entries applicable to the MSIPC client shipped with Office 2016.

  1. Migrate-Client
    • Condition: Runs each computer startup only if it detects it has not run before or the version variable in the script has been changed.
    • Registry Entries Modified:
      • Deletes HKLM\Software\Microsoft\MSIPC\ServiceLocation keys
      • Deletes HKLM\Software\Wow6432Node\Microsoft\MSIPC\ServiceLocation key
      • Deletes HKLM\Software\Microsoft\MSIPC\ServiceLocation\LicensingRedirection key
      • Deletes HKLM\Software\Wow6432Node\Microsoft\MSIPC\ServiceLocation\LicensingRedirection key
      • Add Default value to HKLM\Software\Microsoft\MSIPC\ServiceLocation\EnterpriseCertification key with data value pointing to AIP endpoint for tenant
      • Add Default value to HKLM\Software\Wow6432Node\Microsoft\MSIPC\ServiceLocation\EnterpriseCertification key with data value pointing to AIP endpoint for tenant
      • Add a value for the FQDN and single label URLs to on-premises AD RMS licensing pipeline to HKLM\Software\Microsoft\MSIPC\ServiceLocation\LicensingRedirection key with data values pointing to AIP endpoints for tenant
      • Add a value for the FQDN and single label URLs to on-premises AD RMS licensing pipeline to HKLM\Software\Wow6432NodeMicrosoft\MSIPC\ServiceLocation\LicensingRedirection key with data values pointing to AIP endpoints for tenant
  2. Migrate-User
    • Condition: Runs each user logon only if it detects it has not run before or the version variable in the script has been changed.
    • Registry Entries Modified:
      • Deletes HKCU\Software\Microsoft\Office\16.0\Common\DRM key
      • Deletes HKCU\Software\Classes\Local Settings\Software\Microsoft\MSIPC key
      • Deletes HKCU\Software\Classes\Microsoft.IPViewerChildMenu\shell key
      • Add DefaultServerUrl value to HKCU\Software\Microsoft\Office\16.0\Common\DRM key and set its data value to the AIP endpoint for the tenant
    • Files Modified:
      • Deletes the contents of the %localappdata%\Microsoft\MSIPC folder

A quick review of my client settings validates that all the necessary registry entries are in place and I have no issues consuming and created protected content.

Resetting the Client

If you have administered AD RMS in the past, you will be very familiar with how to re-bootstrap an RMS client.  Microsoft has made that entire process easier by incorporating a “reset” function into the AIP client.  The function can be accessed in Microsoft Office by hitting the drop down arrow for the AIP icon on the toolbar and selecting the Help and Feedback option.

6AIP1.png

After clicking the Help and Feedback option, a new window pops up where you can select the Reset Settings option to which performs a series of changes to the registry, deletions of RMS licenses, and AIP metadata.  Lastly, I log out of the machine.

6AIP2.png

 

Bootstrapping the Client with Azure Information Protection

After logging back in I start up Fiddler, open Microsoft Word, and attempt to open a file that was protected with my AD RMS cluster. The file opens successfully.

One thing to note is if you’re using Windows 10 and Microsoft Edge like I was, you’ll need to take the extra steps outlined here to successfully capture due to the AppContainer Isolation feature added back in Windows 8. If you do not take those extra steps, you’ll get really odd behavior. Microsoft Edge will fail any calls to intranet endpoints (such as AD FS in my case) by saying it can’t contact the proxy. Trying with Internet Explorer will simply cause Fiddler to fail to make the calls and to throw a DNS error. Suffice to say, I spent about 20 minutes troubleshooting the issue before I remembered Fiddler’s dialog box that pops up every new install about AppContainer and Microsoft Edge.

The first thing we’re going to look at is the MSIPC log files which keep track of the client activity. I have to give an applause to whichever engineer over at Microsoft thought it would be helpful to include such a detailed log. If you’ve administered on-premises AD RMS in the past on previous versions of Microsoft Office, you’ll know the joys (pain?) of client side tracing with DebugView.

When we pop open the log we get some great detail as to the client behavior. We can see the client read a number of registry entries. The first thing we see is the client discover that is not initialized so it calls an API to bootstrap the user. Notice in the below that it has identified my user and it’s mentioning OAuth as a method for authentication to the endpoint.

6AIP3.png

Following this we have a few more registry queries to discover the version of the operating system. We then have our first HTTP session opened by the client. I’m pretty sure this session is the initial user authentication to Azure AD in order to obtain a bearer access token for the user to call further APIs

6AIP4.png

Bouncing over to Fiddler we can check out the authentication process. We can see the machine reach out to Azure AD (login.windows.net), perform home realm discovery which Azure AD determines that geekintheweeds.com is configured for federated authentication. The client makes the connection to the AD FS server where the user is seamlessly authenticated via Kerberos. The windowstransport endpoint is called which supports the WS-Trust 1.3 active profile.  In an WS-Trust active flow, the client initiates the request (hence it’s active) vs the passive flow where the service provider initiates the flow.  This is how Office applications support modern (aka federated) authentication.

6AIP5

After the assertion is obtained, it’s posted to the /common/oauth2/token endpoint at login.windows.net.  The assertion is posted within a request for an access token, refresh token, and id token request using the saml1_1-bearer token grant type for the Azure RMS endpoint.

6AIP6.png

The machine is returned an access token, refresh token, and id token.  We can see the token returned is a bearer token allowing client to impersonate my user moving forward.

6AIP7.png

Dumping the access token into the Fiddler TextWizard and decoding the Base64 gives us the details of the token.  Within the token we can see an arm (authenticated method reference) of wia indicating the user authenticated using Windows authentication.  A variety of information about the user is included in the token including UPN, first name, and last name.

6AIP8.png

I’m fairly certain the tokens are cached to a flat file based upon some of the data I did via procmon while the bootstrap process initiated.  You can see the calls to create the file and write to it below.

6AIP9

After the tokens are obtained and cached we see from the log file that the MSIPC client then discovers it doesn’t have machine certificates.  It goes through the process of creating the machine certificates.

6AIP10.png

We now see the MISPC client attempts to query for the SRV record Microsoft introduced with Office 2016 to help with migrations from AD RMS.  The client then attempts discovery of service by querying the RMS-specific registry keys in the HKLM hive and comes across the information we hardcoded into the machine via the migration scripts.  It uses this information to make a request to the non-authenticated endpoint of https://<tenant_specific>/_wmcs/certification/server.asmx.

6AIP11

Bouncing back to Fiddler and continuing the conversation we can see a few different connections are created.  We see one to api.informationprotection.azure.com, another to mobile.pipe.aria.microsoft.com, and yet another to the AIP endpoint for my tenant.

6AIP12.png

I expected the conversation between api.informationprotection.azure.com and the AIP endpoint for my tenant.  The connection to mobile.pipe.aria.microsoft.com interested me.  I’m not sure if it was randomly captured or if it was part of the consumption of protected content.  I found a few Reddit posts where people were theorizing it has something to do with how Microsoft consumes telemetry from Microsoft Office.  As you could probably guess, this piqued my interest to know what exactly Microsoft was collecting.

We can see from the Fiddler captures that an application on the client machine is posting data to https://mobile.pipe.aria.microsoft.com/Collector/3.0/.  Examination of the request header shows the user agent as AriaSDK Client and the sdk-version of ACT-Windows Desktop.  This looks to be the method in which the telemetry agent for Office collects its information.

6AIP13.png

If we decode the data within Fiddler and dump both sets of data to Notepad we get some insight into what’s being pulled. Most of the data is pretty generic in that there is information about the version of Word I’m using, the operating system version, information that my machine is a virtual machine, and some activity IDs which must relate to something MS holds on their end. The only data point I found interesting was that my tenant ID is included in it. Given tenant id isn’t exactly a secret, it’s still interesting it’s being collected. It must be fascinating to see this telemetry at scale. Interesting stuff either way.

6AIP14.png

Continuing the conversation, let’s examine the chatter with my tenant’s AIP endpoint since the discovery was requested by the MSIPC client.  We see a SOAP request of GetServerInfo posted to https://<tenant_specific>/_wmcs/certification/server.asmx.  The response we receive from the endpoint has all the information our RMS client will need to process the request.  My deep dive into AD RMS was before I got my feet with Fiddler so I’ve never examined the conversations with the SOAP endpoints within AD RMS.  Future blog post maybe?  Either way, I’ve highlighted the interesting informational points below.  We can see that the service is identifying itself as RMS Online, has a set of features that cater to modern authentication, runs in Cryptomode 2, and supports a variety of authentication methods.  I’m unfamiliar with the authentication types beyond X509 and OAuth 2.  Maybe carry overs from on-prem?  Something to explore in the future.  The data boxed in red are all the key endpoints the RMS client needs to know to interact with the service moving forward.  Take note the request at this endpoint doesn’t require any authentication.  That comes in later requests.

6AIP15.png

After the response is received the MSIPC writes a whole bunch of registry entries to the HKCU hive for the user to cache all the AIP endpoint information it discovered.  It then performs a service discovery against the authenticated endpoint using its bearer token it cached to the tokencache file.

6AIP16.png

Once the information is written to the registry, the client initiates a method called GetCertAndLicURLsWithNewSD.  It uses the information it discovered previously to query the protected endpoint https://<tenant_specific>/_wmcs/oauth2/servicediscovery/servicediscovery.asmx.  Initially it receives a 401 unauthorized back with instructions to authenticate uses a bearer token.

6AIP17.png

The client tries again this time providing the bearer token it obtained earlier and placed in the tokencache file.  The SOAP action of ServiceDiscoveryForUser is performed and the client requests the specific endpoints for certification, licensing, and the new tracking portal feature of AIP.

6AIP18.png

The SOAP response contains the relevant service endpoints and user for which the query applied to.

6AIP19.png

The MSIPC client then makes a call to /_wmcs/oauth2/certification/server.asmx with a SOAP request of GetLicensorCertificate.  I won’t break that one down response but it returns the SLC certificate chain in XrML format.  For my tenant this included both the new SLC I generated when I migrated to AIP as well as the SLC from my on-premises AD RMS cluster that I uploaded.

6AIP20.png

The MISPC log now shows a method called GetNewRACandCLC being called which is used to obtain a RAC and CLC. This is done by making a call to the certification pipeline.

6AIP21.png

The call to /_wmcs/oauth2/certification/certification.asmx does exactly as you would expect and calls the SOAP request of Certify. This included my user’s RAC, and both SLCs and certificates in that chain. The one interesting piece in the response was a Quota tag as seen below. I received back five certificates, so maybe there is a maximum that can be returned? If you have more than 4 on-premises AD RMS clusters you’re consolidating to AIP, you might be in trouble. 🙂

6AIP22.png

The MISPC log captures the successful certification and logs information about the RAC.

6AIP23.png

Next up the client attempts to obtain a CLC by calling continuing with the GetNewRACandCLC method. It first calls the /_wmcs/licensing/server.asmx pipeline and makes a GetServerInfo SOAP request which returns the same information we saw in the last request to server.asmx. This request isn’t authenticated and the information returned is written to the HKCU hive for the user.

6AIP24.png

The service successfully returns the users CLC.  The last step in the process is the MSIPC service requests the RMS templates associated with the user.  You can see the template that is associated custom AIP classification label I created.

6AIP25.png

Last but not least, the certificates are written to the %LOCALAPPDATA%\Microsoft\MSIPC directory.

6AIP26.png

Conclusion

Very cool stuff right? I find it interesting in that the MSIPC client performs pretty much the same way it performs with on-premises exempting some of the additional capabilities introduced such as the search for the SRV DNS records and the ability to leverage modern authentication via the bearer token. The improved log is a welcome addition and again, stellar job to whatever engineer at Microsoft thought it would be helpful to include all the detail that is included in that log.

If you’ve used AD RMS or plan to use AIP and haven’t peeked behind the curtains I highly recommend it. Seeing how all the pieces fit together and how a relatively simple web service and a creative use of certificates can provide such a robust and powerful security capability will make your appreciate the service AD RMS tried to be and how far ahead of its time it was.

I know I didn’t cover the calls to the AIP-classification specific web calls, but I’ll explore that in my next entry.  Hopefully you enjoyed nerding out on this post as much as I did. Have a great week and see you next post!

Deep Dive into Azure AD Domain Services – Part 3

Deep Dive into Azure AD Domain Services  – Part 3

Well folks, it’s time to wrap up this series on Azure Active Directory Domain Services (AAD DS).  In my first post I covered the basic configurations of the managed domain and in my second post took a look at how well Microsoft did in applying security best practices and complying with NIST standards.  In this post I’m going to briefly cover the LDAPS over the Internet capability, summarize some key findings, and list out some improvements I’d like to see made to the service.

One of the odd features Microsoft provides with the AAD DS service is the ability to expose the managed domain over LDAPS to the Internet.  I really am lost as to the use case that drove the feature.  LDAP is very much a legacy on-premises protocol that has no place being exposed to risks of the public Internet.  It’s the last thing that should the industry should be encouraging.  Just because you can, doesn’t mean you should.   Now let me step off the soap box and let’s take a look at the feature.

As I covered in my last post LDAPS is not natively enabled in the managed domain.  The feature must be configured and enabled through the Azure Portal.  The configuration consists of uploading the private key and certificate the service will use in the form of a PKCS12 file (*.PFX).  The certificate has a few requirements that are outlined in the instructions above.  After the certificate is validated, it takes about 10-15 minutes for the service to become available.  Beyond enabling the service within the VNet, you additionally have the option to expose the LDAPS endpoint to the Internet.

3aads1.png

Microsoft provides instructions on how to restrict access to the endpoint to trusted IPs via a network security group (NSG) because yeah, exposing an LDAP endpoint to the Internet is just a tad risky.  To lock it down you simply associate an NSG with the subnet AAD DS is serving.  Once that is done enable the service via the option in the image above and wait about 10 minutes.  After the service is up, register a external DNS record for the service that points to the IP address noted under the properties section of the AADS blade and you’re good to go.

For my testing purposes, I locked the external LDAPS endpoint down to the public IP address my Azure VM was SNATed to.  After that I created an entry in the host file of the VM that matched the external DNS name I gave the service (whyldap.geekintheweeds.com) to the public IP address of the LDAPS endpoint in order to bypass the split-brain DNS challenge.  Initiating a connection from LDP.EXE was a success.

3aads2.png

Now that we know the service is running, let’s check out what the protocol support and cipher suite looks like.

3aads3.png

Again we see the use of deprecated cipher suites. Here the risk is that much greater since a small mistake with an NSG could expose this endpoint directly to the Internet.  If you’re going to use this feature, please just don’t.  If you’re really determined to, don’t screw up your NSGs.

This series was probably one of the more enjoyable series I’ve done since I knew very little about the AAD DS offering. There were a few key takeaways that are worth sharing:

  • The more objects in the directory, the more expensive the service.
  • Users and groups can be created directly in managed domain after a new organizational unit is created.
  • Password and lockout policy is insanely loose to the point where I can create an account with a three character password (just need to meet complexity requirements) and accounts never lockout.  The policy cannot be changed.
  • RC4 encryption ciphers are enabled and cannot be disabled.
  • NTLMv1 is enabled and cannot be disabled.
  • The service does not support smart-card enforced users.  Yes, that includes both the users synchronized from Azure AD as well as any users you create directly in the managed domain.  If I had to guess, it’s probably due to the fact that you’re not a Domain Admin so hence you can’t add to the NTAuth certificate store.
  • LDAPS is not enabled by default.
  • Schema extensions are not supported.
  • Account-Based Kerberos Delegation is not supported.
  • If you are syncing identities to Azure AD, you’ll also need to synchronize your passwords.
  • The managed domain is very much “out of the box” defaults.
  • Microsoft creates a “god” account which is a permanent member of every privileged group in the forest
  • Recovery of deleted objects created directly in the managed domain is not possible.  The rights have not been delegated to the AADC Administrator.
  • The service does not allow for Active Directory trusts
  • SIDHistory attribute of users and groups sourced from Azure AD is populated with Primary Group from on-premises domain

My verdict on AAD DS is it’s not a very useful service in its current state.  Beyond small organizations, organizations that have very little to no requirements on legacy infrastructure, organizations that don’t have strong security requirements, and dev/qa purposes I don’t see much of a use for it right now.  It comes off as a service in its infancy that has a lot of room to grow and mature.  Microsoft has gone a bit too far in the standardization/simplicity direction and needs to shift a bit in the opposite direction by allowing for more customization, especially in regards to security.

I’d really like to see Microsoft introduce the capabilities below.   All of them should  exposed via the resource blade in the Azure Portal if at all possible.  It would provide a singular administration point (which seems to be the strategy given the move of Azure AD and Intune to the Azure Portal) and would allow Microsoft to control how the options are enabled in the managed domain.  This means no more administrators blowing up their Active Directory forest because they accidentally shut off all the supported cipher suites for Kerberos.

  • Expose Domain Controller Event Logs to Azure Portal/Graph API and add support for AAD DS Power BI Dashboards
  • Support for Active Directory trusts
  • Out of the box provide a Red Forest model (get rid of that “god” account)
  • Option to disable risky cipher suites for both Kerberos and LDAPS
  • Option to harden the password and lockout policy
  • Option to disable NTLMv1
  • Option to turn on LDAP Debug Logging
  • Option to direct Domain Controller event logs to a SIEM
  • Option to restore deleted users and groups that were created directly in the managed domain.  If you’re allow creation, you need to allow for restoration.
  • Removal of Internet-accessible LDAPS endpoint feature or at least somehow incorporate the NSG lockdown feature directly into the AAD DS blade.

While the service has a lot of room for improvement the direction of a managed Windows AD offering is spot on.  In the year 2018, there is no reason Windows AD shouldn’t be offered as a managed service.  The direction Microsoft has gone by sourcing the identities and credentials from Azure AD is especially creative.  It’s a solid step in the direction of creating a singular centralized identity service that provides both legacy and modern protocols.  I’ll be watching this service closely as Microsoft builds upon it for the next few months.

Thanks and see you next post!