Exchange Edge Server and Common Attachment Blocking In Exchange Online Protection

Posted on Leave a commentPosted in 2007, 2010, 2013, 2016, Edge, EOP, exchange, exchange online, Exchange Online Protection, FOPE, IAmMEC, Office 365

Both Exchange Server Edge role and Exchange Online Protection have an attachment filtering policy. The default in Edge Server is quite long, and the default in EOP is quite short. There is also a few values that are common to both.

So, how do you merge the lists so that your Edge Server attachment filtering policy is copied to Exchange Online in advance of changing your MX record to EOP?

You run

Set-MalwareFilterPolicy Default -FileTypes ade,adp,cpl,app,bas,asx,bat,chm,cmd,com,crt,csh,exe,fxp,hlp,hta,inf,ins,isp,js,jse,ksh,lnk,mda,mdb,mde,mdt,mdw,mdz,msc,msi,msp,mst,ops,pcd,pif,prf,prg,ps1,ps11,ps11xml,ps1xml,ps2,ps2xml,psc1,psc2,reg,scf,scr,sct,shb,shs,url,vb,vbe,vbs,wsc,wsf,wsh,xnk,ace,ani,docm,jar

This takes both the Edge Server default list and the EOP default list, minus the duplicate values and adds them to EOP. If you have a different custom list then use the following PowerShell to get your two lists and then use the above (with “Default” being the name of the policy) PowerShell to update the list in the cloud

Edge Server: Get-AttachmentFilterEntry

EOP: $variable = Get-MalwareFilterPolicy Default
$variable.FileTypes

Photos, Exchange, And The File System

Posted on 1 CommentPosted in 2013, 2016, Exchange Server, Office 365, owa

On an Exchange 2013 and later server this is a folder called photos that gets created after installation and can contain a couple of user photos for some of your users. How does it get there and what does it contain?

The photos folder appears (on 2016 anyway) when the user uploads a photo (via OWA). Two images are created one 96square and the other 648square. They are made in a folder unique to the user and on the mailbox server that contains their active mailbox at the time of upload.

To reproduce this, login to OWA. Determine which server is currently the active server for that mailbox and then access the file system of that server. You are looking for “C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess” though it will be wherever Exchange Server was installed if not the C: drive. If anyone has uploaded photos already via this server then you will see a folder named photo. You can delete this folder without impact (unless someone is actively uploading a photo at that exact time).

In OWA, click the photo icon top right and then click Change:

image

image

Click Upload photo and select a photo. I’ve used the sample pictures that are installed on Windows 7 in this example:

image

At this point a copy of the photo is uploaded to a web service on Exchange Server. Click Save above your chosen photo. At this point the photo folder in the ClientAccess folder on the server that is active for your mailbox is created. Inside this folder you will see a subfolder called _domain.com-UNIQUEID. Inside this folder will be two subfolders called HR96x96 and HR648x648. Inside each of these will be the JPEG file that was created at the time of saving the upload. The size of each will match the folder name and the name of the file will be _Alias-UNIQUEID. If the user deletes their photo then a 0 byte JPEG file will be created in the folder.

Note that these two photos are not a cache of the photo for the Exchange Server to download to other users. They are just used during uploading the photos. Once uploaded they are resized using this file system location and then stored in their respective locations. The 96×96 photo (at less than 100Kb) is stored in the Active Directory and the 648×648 image is stored in the Exchange 2013 or later mailbox for use by Exchange, Skype for Business and SharePoint.

If there are policies and privacy laws that state the caching of images on the file system must be avoided, then you should be able to delete the photo upload cache at your convenience.

The photo folder does not appear on another server when viewing that user with a photo in their mailbox. Requesting the photo is done via owa/service.svc and not AFAIK from a file on the file system.

Deleting the folder after the fact did not impact my test users photo (as its now in the mailbox and not read from the file system). If this mailbox is later migrated to Office 365, then the photo will migrate with the mailbox as it is part of the mailbox. If the photo stored in AD is less than 100kb then it will be synced to Azure AD.

Exchange Server and Missing Root Certificates

Posted on Leave a commentPosted in 2007, 2010, 2013, exchange, exchange online, Exchange Server, federation, Free/Busy

I came across an issue with a clients Exchange Server deployment today that is not well documented – or rather it is, but you need to know where to look. So I thought I would document the troubleshooting steps and the fix here.

We specifically came across this error when testing Free/Busy for an Office 365 migration, though it could happen for a variety of reasons. Free/Busy and other lookups in a cross-forest Exchange Server deployment require a working organization configuration and this was failing. Running Test-FederationTrust (a prerequisite of the organization relationship) in verbose mode (add -Verbose to the end) returned the following:

Unable to retrieve federation metadata from the security token
service. Reason: Microsoft.Exchange.Management.FederationProvisioning.FederationMetadataException: Unable to access the
Federation Metadata document from the federation partner. Detailed information: “The underlying connection was closed:
Could not establish trust relationship for the SSL/TLS secure channel.”.

The final result of the test will also show two errors for “Unable to retrieve federation metadata from the security token service.” and “Failed to request delegation token.”

The last part of the verbose error is the clue here. The server in question is unable to make an SSL/TLS connection to the endpoint that the federation trust needs to reach to get the federation trust metadata. That endpoint is listed right at the start of the Verbose output. It reads:

VERBOSE: [16:53:08.306 GMT] Test-FederationTrust : Requesting Federation Metadata from
https://nexus.microsoftonline-p.com/FederationMetadata/2006-12/FederationMetadata.xml.

Now that we have a URL and an error message, check that the URL is reachable from each of your Exchange Servers. At my client today we found one server could not successfully reach this endpoint without an SSL error turning up in the browser. The problem was that the certificate that the endpoint is secure with is issued by the Baltimore Cybertrust Root Certificate – one that Microsoft uses for lots of services, but the root certificate was not installed on that machine. Lots of root certs where missing from that machine as it had never had a root certificate update applied to it.

We installed the latest Root Certificate Update and then the federation trust worked and free/busy etc. (mail tips, cross-forest message tracking etc.) all worked fine.

Qualifications in Exchange Signatures

Posted on Leave a commentPosted in 2013, active directory, exchange, Exchange Server, Global Catalog, IAmMEC, iQ.Suite

In a recent project I was working with iQ.Suite from GBS and specifically the component of this software that add signatures to emails. The client are an international organization with users in different geographies and we needed to accommodate the users qualifications in their email signature.

The problem with this is that in Germany qualifications are written in front of the name and in the USA at the end and in other countries at the start and the end. We were doing a Notes to Exchange migration and in Notes the iQ.Suite signature software read data from Notes that was originally pulled from Active Directory, and so the client had placed the qualifications in the DisplayName field in the Active Directory.

But when we migrated to Exchange Server the Global Address List listed the users DisplayName an so the German users where all listed together with “Dipl” as the first characters of their name. Also the name the email came from was written like this. The signature worked, but the other changes that became apparent meant we had to work out a different way to look at this problem.

So rather than using DisplayName for the users name and qualifications, we used personalPrefix in Active Directory to store anything needed before their name (Dipl in the above German example, and Prof or Dr being English examples) and the generationQualifier Active Directory attribute to store any string that followed the users DisplayName (such as Jr in the USA or BSc for qualifications etc.)

In iQ.Suite we created a signature that looked like the following. This has a conditional [COND] entry for personalTitle, displayName and generationQualifier. That is if each of these are present, then show the displayName with personalTitle before it and generationQualifier after it. If the user does not have values for these fields, do not show them. The [COND] control is documented in iQ.Suite.

[COND]personalTitle;[VAR]personalTitle[/VAR] [/COND][COND]displayName;[VAR]displayName[/VAR][/COND][COND]generationQualifier; [VAR]generationQualifier[/VAR][/COND]

What was not so well documented, and why I wanted to write this blog entry was that the personalTitle and generationQualifier attributes are not stored in the Global Catalog and so are missing in the users signature. In the multi-domain deployment we had at the client, iQ.Suite read the personalTitle, displayName and generationQualifier Active Directory attributes from the Global Catalog as Exchange was installed in a resource domain and the users in separate domains and so unless the attribute was pushed to the Global Catalog it was not seen by iQ.Suite.

To promote an attribute to be visible in the Global Catalog you need to open the Schema Management MMC snap-in, find the attributes of question and tick the Replicate this attribute to the Global Catalog field. This is outlined in https://technet.microsoft.com/en-us/library/cc737521(v=ws.10).aspx.

Unable To Send Exchange Quota Message

Posted on Leave a commentPosted in 2010, 2013, exchange, IAmMEC

In Exchange 2013 you can sometimes see the following event log error (MSExchange Store Driver Submission, ID 1012):

The store driver failed to submit event <id> mailbox <guid> MDB <database guid> and couldn’t generate an NDR due to exception Microsoft.Exchange.MailboxTransport.StoreDriverCommon.InvalidSenderException
   at Microsoft.Exchange.MailboxTransport.Shared.SubmissionItem.SubmissionItemUtils.CopySenderTo(SubmissionItemBase submissionItem, TransportMailItem message)
   at Microsoft.Exchange.MailboxTransport.Submission.StoreDriverSubmission.MailItemSubmitter.GenerateNdrMailItem()
   at Microsoft.Exchange.MailboxTransport.Submission.StoreDriverSubmission.MailItemSubmitter.<>c__DisplayClass1.<FailedSubmissionNdrWorker>b__0()
   at Microsoft.Exchange.MailboxTransport.StoreDriverCommon.StorageExceptionHandler.RunUnderTableBasedExceptionHandler(IMessageConverter converter, StoreDriverDelegate workerFunction).

And this will be preceded by the following event log warning (MSexchangeIS, ID 1077):

The mailbox <guid> on database <database guid> is approaching its storage limit. A notification has been sent to the user. This warning will not be sent again for at least twenty four hours.

The mailbox in both errors is the same and it occurs for mailboxes that have moved to Exchange Server 2013 from Exchange Server 2010 and are close to their mailbox quota. To fix the issue move the mailbox to a different database. The easiest way to do this is New-MoveRequest <guid> where the same GUID is used.

If you have lots of these then this is a little more time consuming, unless you get PowerShell to the rescue.

The following two cmdlets will query the last seven days of the event logs for MSexchangeIS sourced events with ID 1077, get the event log message (which contains the mailbox guid), manipulate the string containing the message and generate a text file of just the mailbox guids. The second cmdlet will run a New-MoveRequest for each mailbox listed in the text file.

Get-WinEvent -ComputerName PC1 -ProviderName MSExchangeIS | where {$_.ID -eq 1077 -AND $_.TimeCreated -gt [DateTime]::Now.AddDays(-7).Date} | select @{Name="mailbox";Expression={$_.Message.Substring(12,36)}} | ft -HideTableHeaders -AutoSize | out-file nearquota.txt

and then

Get-Content .\nearquota.txt | foreach {New-MoveRequest -Identity $_}

Make sure though that your Application event log is large enough to store more than seven days of events and then run these cmdlets, per server every seven days until the issue goes away (or over the course of say a year, move all mailboxes to different databases and that fixes it as well).

Exchange OWA and Multi-Factor Authentication

Posted on 16 CommentsPosted in 2010, 2013, Azure, exchange, IAmMEC, MFA, MVP, owa, smartphone

Multi-factor authentication (MFA), that is the need to have a username, password and something else to pass authentication is possible with on-premises servers using a service from Windows Azure and the Multi-Factor Authentication Server (an on-premises piece of software).

The Multi-Factor Authentication Server intercepts login request to OWA, if the request is valid (that is the username and password work) then the mobile phone of the user is called or texted (or an app starts automatically on the phone) and the user validates their login. This is typically done by pressing # (if a phone call) or clicking Verify in the app, but can require the entry of a PIN as well. Note that when the MFA server intercepts the login request in OWA, there is no user interface in OWA to tell you what is happening. This can result in user disconnect and stops the use of two-way MFA (receive number by text, type number into web application type scenario). Therefore to that end, MFA directly on the OWA application is not supported by the Microsoft Exchange team. Steps for setting up ADFS for Exchange Server 2013 SP1 or later are at https://technet.microsoft.com/en-us/library/dn635116(v=exchg.150).aspx. Once this is in place, you need to enable MFA for ADFS rather than MFA for OWA. I have covered this in a separate post at http://c7solutions.com/2016/04/installing-azure-multi-factor-authentication-and-adfs.

To configure Multi-Factor Authentication Server for OWA (unsupported) you need to complete the following steps:

Some of these steps are the same regardless of which service you are adding MFA to and some slightly different. I wrote a blog on MFA and VPN at http://c7solutions.com/2015/01/windows-rras-vpn-and-multi-factor-authentication and this contains the general setup steps and so these are not repeated here. Just what you need to do differently

Step 1

See http://c7solutions.com/2015/01/windows-rras-vpn-and-multi-factor-authentication

Step 2: Install MFA Server on-premises

This is covered in http://c7solutions.com/2015/01/windows-rras-vpn-and-multi-factor-authentication, but the difference with OWA is that it needs to be installed on the Exchange CAS server where the authentication takes place.

Ensure you have .NET 3.5 installed via Server Manager > Features. This will install the .NET 2.0 feature that is required by MFA server. If the installation of the download fails, this is the most likely reason for the failure, so install .NET 3.5 and then try the MFA Server install again.

The install of the MFA server does not take very long. After a few minutes the install will complete and then you need to run the Multi-Factor Authentication Server admin tools. These are on the Start Screen in More Apps or the Start Menu. Note that it will start the software itself if given time:

image

image

Do not skip the wizard, but click Next. You will be asked to activate the server. Activating the server is linking it to your Azure MFA instance. The email address and password you need are obtained from the Azure multi-factor auth provider that was configured in Step 1. Click the Generate Activation Credentials on the Downloads page of the Azure MFA provider auth management page.

image

The credentials are valid for ten minutes, so your will differ from mine. Enter them into the MFA Server configuration wizard and click Next.

MFA Server will attempt to reach Azure over TCP 443.

Select the group of servers that the configuration should replicate around. For example, if you where installing this software on each Exchange CAS server, then you might enter “Exchange Servers” as the group name in the first install and then select it during the install on the remaining servers. This config will be shared amongst all servers with the same group name. If you already have a config set up with users in it and set up a new group here, then it will be different settings for the users. For example you might have a phone call to authenticate a VPN connection but use the app for OWA logins. This would require two configs and different groups of servers. If you want the same settings for all users in the entire company, then one group (the default group) should be configured.

image

Next choose if you want to replicate your settings. If you have more than one MFA Server instance in the same group select yes.

Then choose what you want to authenticate. Here I have chosen OWA:

image

Then I need to choose the type of authentication I have in place. In my OWA installation I am using the default of Forms Based Authentication, but if you select Forms-based authentication here, the example URL for forms based authentication shown on the next page is from Exchange Server 2003 (not 2007 or later). Therefore I select HTTP authentication

Next I need to provide the URL to OWA. I can get this by browsing the OWA site over https. The MFA install will also use HTTPS, so you will need a certificate and have this trusted by a third party if you want to support user managed devices. Users managing their own MFA settings (such as telephone numbers and form of authentication) reduces the support requirement. That needs the User Portal, the SDK and the Mobile App webservice installed as well. These are outside the scope of this blog. For here I am going to use https://servername/owa.

image

Finish the installation at this time and wait for the admin application to appear.

Step 3: Configure Users for MFA

Here we need to import the users who will be authenticated with MFA. Select the Users area and click Import from Active Directory. Browse the settings to imports group members, or OUs or a search to add your user account. Once you have it working for yourself, add others. Users not listed here will not see any change in their authentication method.

Ensure that your test user has a mobile number imported from the Active Directory. If not add one, choosing the correct country code as well. The default authentication for the user is that they will get a phone call to this number and need to press # before they can be logged in. Ensure that the user is set to Enabled as well in the users area of the management program.

Step 4: Configure OWA for MFA (additional steps)

On the IIS Authentication node you can adjust the default configuration for HTTP. Here you need to set Require Multi-Factor Authentication user match. This ensures that each auth attempt is matched to a user in the users list. If the user exists and is enabled, then do MFA for them. If disabled, then the setting for Succeed Authentication on the advanced tab comes into play. If the user is not listed, authentication passes through without MFA.

image

Change to the Native Module tab and select OWA under Default Web Site only. Do not set authentication on the Backend Web Site. Also enable the native module on ECP on the Default Web Site as well:

image

Then I can attempt a login to OWA or ECP. Once I successfully authenticate my phone rings and I am prompted to press #. Once I press # I am allowed into Exchange!

SSL and Exchange Server

Posted on 2 CommentsPosted in 2008 R2, 2012 R2, 2013, certificates, exchange, https, IAmMEC, JetNexus, load balancer, Load Master, loadbalancer, mobile phones, SSL, TLS, windows server, xp

In October 2014 or thereabouts it became known that the SSL protocol (specifically SSL v3) was broken and decryption of the encrypted data was possible. This blog post sets out the steps to protect your Exchange Server organization regardless of whether you have one server or many, or whether or not you use a load balancer or not. As load balancers can terminate the SSL session and recreate it, it might be that changes are needed on your load balancer or maybe directly on the servers that run the CAS role. This blog post will cover both options and looks at the settings for a Kemp load balancer and a JetNexus load balancer.

Of course being an Exchange Server MVP, I tend to blog about Exchange related stuff, but actually this is valid for any server that you publish to the internet and probably valid of any internal server that you encrypt traffic to via the SSL suite of protocols. Microsoft outline the below configuration at https://technet.microsoft.com/en-us/library/security/3009008.aspx.

The steps in this blog will look at turning off the SSL protocol in Windows Server and turning on the TLS protocol (which does the same thing as SSL and is interchangeable for SSL, but more secure at the time of writing – Jan 2015). Some clients do not support TLS (such as Internet Explorer on Windows XP Service Pack 2 or earlier, so securing your servers as you need to do may stop some home users connecting to your Exchange Servers, but as XP SP2 should not be in use in any business now, these changes should not affect desktops. You could always use a different browser on XP as that might mitigate this issue, but using XP is a security risk in an of itself anyway! To disable clients from connecting to SSL v3 sites requires a client or GPO setting and this can be found via your favourite search engine.

Note that the registry settings and updates for the load balancers in this blog post will restrict client access to your servers if your client cannot negotiate a mutual cipher and secure channel protocol. Therefore care and testing are strongly advised.

Testing and checking your changes

Before you make any changes to your servers, especially internet facing ones, check and document what you have in place at the moment using https://www.ssllabs.com/ssltest. This service will connect to an SSL/TLS protected web site and report back on the issues found. Before running any of the changes below see what overall rating you get and document the following:

  • Authentication section: record the signature algorithm. For the signature algorithm its possible the certificate authority signature will be marked “SHA1withRSA WEAK SIGNATURE”. This certificate, if rekeyed and issued again by your certificate authority might be replaced with a SHA-2 certificate. The Google Chrome browser from September 2014 will report sites secured with this SHA-1 certificate as not fully trustworthy based on the expiry date of the certificate. If your certificate expires after Jan 1st 2017 then get it rekeyed as soon as possible. As 2015 goes on, this date will move closer in time. From early 2015 this cut off date becomes June 1st 2016 and so on. Details on the dates for this impact are in http://googleonlinesecurity.blogspot.co.uk/2014/09/gradually-sunsetting-sha-1.html. You can also use https://shaaaaaaaaaaaaa.com/ to test your certificate if the site is public facing, and this website gives details on who is now issuing SHA-2 keyed certificates. You can examine your external servers for SHA-1 certificates and the impact in Chrome (and later IE and Firefox) at https://www.digicert.com/sha1-sunset/. To do the same internally, use the DigiCert Certificate Inspector at https://www.digicert.com/cert-inspector.htm.
  • Authentication section: record the path values. Ensure that each certificate is either in the trust store or sent by the server and not an extra download.
  • Configuration section: document the cipher suites that are provided by your server
  • Handshake simulation section: Here it will list browsers and other devices (mobile phones) and what their default cipher is. If you do not support the cipher they support then you cannot communicate. Note that you typically support more than one cipher and the client will often support more than one cipher to, so though it is shown here as a mismatch this does not mean that it will not work and if this client is used by your users then click the link for the client and ensure that the server offers at least one of the the ciphers required by the client – unless all the ciphers are insecure in which case do not use that client!

Once you have a document on your current configuration, and a list of the clients you need to support and the ciphers they need you to support, you can go about removing SSL v3 and insecure ciphers.

Disabling SSL v3 on the server

To disable SSL v3 on a Windows Server (2008 or later) you need to set the Enabled registry value at “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\SSL 3.0\Server” to 0. If this value does not exist, the create a DWORD value called “Enabled” and leave it at 0. You then need to reboot the server.

If you are using Windows 2008 R2 or earlier you should enable TLS v1.1 and v1.2 at the same time. Those versions of Windows Server support TLS v1.1 and v1.2 but it is not enabled (only TLS v1.0 is enabled). To enable TLS v1.1 and v1.2 use set the Enabled value at “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.1\Server” to 1. Change the path to “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.2\Server” and the same setting to support TLS v1.2. If these keys do not exist, create them. It is also documented that the “DisabledByDefault” key is required, but I have seen this noted as being the same as the “Enabled” key – just the opposite value. Therefore as I have not actually checked, I set both Enabled to 1 and DisabledByDefault to 0.

To do both the disabling of SSL v2 and v3 (v2 can be enabled on older versions of Windows and should be disabled as well) I place the following in a .reg file and double click it on each server, followed by a reboot for it to take effect. This .reg file contents also disables the RC4 ciphers. These ciphers have been considered insecure for a few years and when I configure my servers not to support SSL v3 I also disable the RC4 ciphers as well.

Windows Registry Editor Version 5.00

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\SSL 2.0]

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\SSL 2.0\Client]

"Enabled"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\SSL 2.0\Server]

"Enabled"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\SSL 3.0]

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\SSL 3.0\Client]

"Enabled"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\SSL 3.0\Server]

"Enabled"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Ciphers\RC4 128/128]

"Enabled"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Ciphers\RC4 40/128]

"Enabled"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Ciphers\RC4 56/128]

"Enabled"=dword:00000000

Then I use the following .reg file to enabled TLS v1.1 and TLS v1.2

Windows Registry Editor Version 5.00

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.1]

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.1\Client]

"Enabled"=dword:00000001

"DisabledByDefault"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.1\Server]

"Enabled"=dword:00000001

"DisabledByDefault"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.2]

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.2\Client]

"Enabled"=dword:00000001

"DisabledByDefault"=dword:00000000

 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Protocols\TLS 1.2\Server]

"Enabled"=dword:00000001

"DisabledByDefault"=dword:00000000

 

Once you have applied both of the above sets of registry keys you can reboot the server at your convenience. Note that the regkeys may set values that are already set, for example TLS v1.1 and v1.2 are enabled on Exchange 2013 CAS servers and SSL v2 is disabled. For example the first of the below graphics comes from a test environment of mine that is running Windows Server 2012 R2 without any of the above registry keys set on them. You can see that Windows Server 2012 R2 is vulnerable to the POODLE attack and supports the RC4 cipher which is weak.

image

The F grade comes from patched but un-configured with regards to SSL Windows Server 2008 R2 server

image

After setting the above registry keys and rebooting, the test at https://www.ssllabs.com/ssltest then showed the following for 2012 R2 on the left (A grade) and Windows Server 2008 R2 on the right (A- grade):

image image

Disabling SSL v3 on a Kemp LoadMaster load balancer

If you protect your servers with a load balancer, which is common in the Exchange Server world, then you need to set your SSL and cipher settings on the load balancer, unless you are only balancing at TCP layer 4 and doing SSL pass through. Therefore even for clients that have a load balancer, you might not need to make the changes on the load balancer, but on the server via the above section instead. If you do SSL termination on the load balancer (TCP layer 7 load balancing) then I recommend setting the registry keys on the Exchange servers anyway to avoid security issues if you need to connect to the server directly and if you are going to disable SSL v3 in one location (the load balancer) there is no problem in disabling it on the server as well.

For a Kemp load balancer you need to be running version 7.1-20b to be able to do the following, and to ensure that the SSL code on the load balancer is not susceptible to issues such as heartbleed as well. To configure your load balancer to disable SSL v3 you need to modify the SSL properties of the virtual server and check the “Support TLS Only” option.

To disable the RC4 weak ciphers then there are a few choices, but the easiest I have seen to do is to select “Perfect Forward Secrecy Only” under Selection Filters and then add all the listed filters. Then from this list remove the three RC4 ciphers that are in the list.

If you do not select “Support TLS Only” and leave the ciphers at the default level then your load balancer will get an C grade at the test at https://www.ssllabs.com/ssltest because it is vulnerable to the POODLE attack. Setting just the “Support TLS Only” option and leaving the default ciphers in place will result in a B grade, as RC4 is still supported. Removing the RC4 ciphers (by following the instructions above to add the perfect forward secrecy ciphers and remove the RC4 ciphers from this list) as well as allowing only the TLS protocol will result in an A grade.

image

Kemp 7.1-22b does not support SSL v3 for the API and web interface as well as completing the above to protect the virtual services that the load balancer offers.

Kemp Technologies document the above steps at https://support.kemptechnologies.com/hc/en-us/articles/201995869, and point out the unobvious setting that if you filter the cipher list with the “TLS 1.x Ciphers Only” setting then it will only show you the TLS 1.2 ciphers and not any TLS 1.1 or TLS 1.0 ciphers. THerefore selecting “TLS 1.x Ciphers Only” rather than filtering using “Perfect Forward Secrecy Only” will result in a reduced client list, which may be an issue.

I was able to achieve an A grade on the SSL Labs test site. My certificate uses SHA-1, but expires in 2015 so by the time SHA-1 is reported an issue in the browser I will have changed it anyway.

image

Disabling SSL v3 on a JetNexus ALB-X load balancer

If you protect your servers with a load balancer, which is common in the Exchange Server world, then you need to set your SSL and cipher settings on the load balancer, unless you are only balancing at TCP layer 4 and doing SSL pass through. Therefore even for clients that have a load balancer, you might not need to make the changes on the load balancer, but on the server via the above section instead. If you do SSL termination on the load balancer (TCP layer 7 load balancing) then I recommend setting the registry keys on the Exchange servers anyway to avoid security issues if you need to connect to the server directly and if you are going to disable SSL v3 in one location (the load balancer) there is no problem in disabling it on the server as well.

For a JetNexus ALB-X load balancer you need to be running build 1553 or later. Build 1553 is a version 3 build, so any version 4 build is of a higher, and therefore valid build. This build (version 3.54.3) or later is needed to ensure Heartbleed mitigation and to allow the following configuration changes to be applied.

To configure the JetNexus  you need to upload a config file to turn off SSL v3 and RC4 ciphers. The config file is .txt file that is uploaded to the load balancer. In version 4, the primary cluster node can have the file uploaded to it, and the changes are replicated to the second node in the cluster automatically.

Before you upload a config file to make the changes required, ensure that you backup the current configuration from Advanced >> Update Software and click the button next to Download Current Configuration to save the configuration locally. Ensure you backup all nodes in a v4 cluster is appropriate.

Then select one of the three config file settings below and copy it to a text file and upload it from Advanced >> Update Software and use the Upload New Configuration option to install the file. The upload will reset all connections, do do this at during a quiet period of time.

The three configs are to reset the default ciphers, to disable SSL v3 and RC4, and to disable TLS v1.0 and SSL v3 and RC4

JetNexus protocol and cipher defaults:

#!update

 

[jetnexusdaemon]

Cipher004="ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL:!EDH"

Cipher1=""

Cipher2=""

CipherOptions="CIPHER_SERVER_PREFERENCE"

JetNexus protocol and cipher changes to disable SSL v3 and disable RC4 ciphers:

#!update

 

[jetnexusdaemon]

Cipher004="ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:HIGH:!MD5:!aNULL:!EDH:!RC4"

Cipher1=""

Cipher2=""

CipherOptions="NO_SSLv3,CIPHER_SERVER_PREFERENCE"

JetNexus protocol and cipher changes to disable TLS v1.0, SSL v3 and disable RC4 ciphers:

#!update

 

[jetnexusdaemon]

Cipher004="ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:HIGH:!MD5:!aNULL:!EDH:!RC4"

Cipher1=""

Cipher2=""

CipherOptions="NO_SSLv3,NO_TLSv1,CIPHER_SERVER_PREFERENCE"

On my test environment I was able to achieve an A- grade with the SSL Test website and the config to disable TLS 1.0, SSL3 and RC4 enabled. The A- is because of a lack of support for Forward Secrecy with the reference browsers used by the test site.

image

Browsers and Other Clients

There too much to discuss with regards to clients, apart from they need to support the same ciphers as mentioned above. A good guide to clients can be found at https://www.howsmyssl.com/s/about.html and from there you can test your client as well.

Additional comment 23/1/15 : One important comment to make though comes courtesy of Ingo Gegenwarth at https://ingogegenwarth.wordpress.com/2015/01/20/hardening-ssltls-and-outlook-for-mac/. This post discusses the TLS Renegotiation Indication Extension update at RFC 5746. It is possible to use the AllowInsecureRenegoClients registry key at HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL to ensure that only clients with the update mentioned at http://support.microsoft.com/kb/980436 are allowed to connect. If this is enabled (set to Strict Mode) and the above to disable SSL 2 and 3 is done then Outlook for Mac clients cannot connect to your Exchange Server. If this regkey is deleted or has a non-zero value then connections to SSL 2 and 3 can be made, but only for a renegotiation to TLS. Therefore ensure that you allow Compatibility Mode (which is the default) when you disable SSL 2 and 3, as Outlook for Mac and Outlook for Mac for Office 365 both require SSL support to then be able to start a TLS session.

The Case of the Disappearing Folders

Posted on 3 CommentsPosted in 2013, exchange online, IAmMEC, MVP, Office, Office 365 ProPlus, Outlook

Here is a issue I have come across at one of my current clients – you create a folder in Outlook 2013 when in the “Mail” view (showing only mail folders – your typical default view) and the folder does not get created. For example, in the below picture the user is in the middle of creating a folder called “Test Inline” as a child of the “SO” folder:

image

Upon pressing Enter, the folder disappears and fails to be created:

image

So where does one see this issue? It happens when the parent folder in question, in this case the “SO” folder is created by Microsoft’s PST Capture Tool. The PST Capture Tool creates a parent folder in the Online Archive in Exchange (in this case Exchange Online but it does not matter which Exchange Server) named after the PST file, so in this case SO.pst was uploaded by the PST Capture Tool. Any attempt to create folders inline below this parent folder fails! If you drag content into this folder it will not allow you to drop the content in, and the folder appears to be read-only.

If you change Outlooks view to Folder view (click the … on the Outlook 2013 view bar to the right) then you can create folders (using a dialog) and that works fine – this is how “Test Dialog” was made in the above pictures.

In Outlook 2010 all works as expected! In Outlook 2013 the issue appears to be the way Outlook handles folders that have a MAPI property on the folder created with a null value. In tools such as MFCMapi and OutlookSpy you can view the MAPI properties of a folder and the folder created by PST Capture Tool has a property call PR_CONTAINER_CLASS_W with a null (empty) value. Normally, Outlook will make folders that have “IPF.Note” as the value of this folder, if this is a mail and notes folder (i.e. not a calendar or contact etc folder). But clearly there is a problem, as Folder view allows you to create subfolders when the parent’s PR_CONTAINER_CLASS_W value is null and so does Outlook 2010 and coincidently does OWA!

The fix, but I do not have it ready yet, is to run an EWS script to reset the PR_CONTAINER_CLASS_W property of this folder to IPF.Note or wait for an update to Outlook from Microsoft, and for that I have contacted them.

With thanks to fellow MVP Jaap Wesselius for double-checking this for me and testing it in Outlook 2010.

Group Policy Import To Fix Google Chrome v37 Issues With Exchange Server and Microsoft CRM

Posted on 2 CommentsPosted in 2010, 2013, Chrome, crm, Dynamics, exchange, exchange online, Group Policy, IAmMEC, Office 365, owa

A recent update to Google Chrome (37.0.2062.120) removed the ability to support modal dialog boxes. This are dialogs that require your attention and stop you going back to the previous page until you have completed the info required – these are very useful in workflow type scenarios.

Google claim that as 0.004% of web sites use them (from Google anonymous statistics gathering that you can opt into in Chrome) they are justified in removing support for them – but they have not removed other things that have the same level of support!

With this version of Chrome (or the Chromium open source browser) there is a work around until April 30th 2015 that will allow modal dialogs to work again. Without this work around clicking links in OWA and ECP in Exchange 2010 and OWA and EAC in Exchange Online and Exchange 2013 will not popup. This can cause issues such as the inability to attach files in OWA and to create objects in ECP/EAC for the administrator. Popups in Microsoft CRM also do not work.

As a work around you could use a different browser, but if Chrome works for you (or does not in this case) and you are joined to a domain then you can download the following GPO export file and import it into your Active Directory to enable modal dialogs to work again in Exchange Server, Office 365 and Microsoft CRM products.

To download and import this GPO file to enable Chrome modal dialog box functionality to resume (until 30th April 2015, when Google stop allowing the work around) follow these steps:

  1. Download Google Chrome Show Modal Dialog Before 30 April 2015.zip
  2. Copy to a domain controller and expand the zip file. Ensure the contents of the zip file are not placed directly on your desktop as you cannot import from the desktop directly, so if you expand the zip to the desktop then copy the one folder that was created into a new subfolder.
  3. Start Group Policy Management MMC admin tool.
  4. Expand Forest > Domain > Your Domain > Group Policy Objects.
  5. Right click “Group Policy Objects” and choose New
  6. Create a new GPO called “Chrome and Chromium Modal Dialog Box Allow”:
    image
  7. Right click “Chrome and Chromium Modal Dialog Box Allow” GPO that you just made and choose Import Settings
  8. Proceed through the import wizard. You do not need to backup this new GPO on the second page of the dialog as the new GPO is empty.
  9. On the third page of the wizard browse to the parent folder containing the contents of the download above:
    image
  10. Click Next and you should see one backed up GPO listed:
    image
  11. Click Next to import this. If you click View Settings first a web page will open showing you that this GPO sets two registry keys for the computer and two registry keys for the user. These set SOFTWARE\Policies\Chromium\EnableDeprecatedWebPlatformFeatures and Software\Policies\Google\Chrome\EnableDeprecatedWebPlatformFeatures (for both Chromium and Chrome browsers) with a reg key (type string) 1:ShowModalDialog_EffectiveUntil20150430
  12. Proceed with Next and then Finish and the import will begin:
    image
  13. Click OK.
  14. Now link the GPO object to the root of your domain so it impacts all users and to the root of any OU that blocks inheritance. Import to other domains as above or link from this domain depending upon your current policy for managing GPO cross domains.
  15. Delete the zip and folder you downloaded. They are not needed any more.