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mdatp security web windows 10

Free Web Content Filtering With Microsoft Defender ATP

Well free as in you need an MDATP licence first, but as this used to be an add on feature on top of MDATP with an additional cost, this is now effectively free once you are licensed for MDATP. The feature enables your organisation to track and regulate access to websites based on their content categories. Many of these websites, while not malicious, might be problematic due to compliance regulations, bandwidth usage, or other concerns.

So how do you set it up from scratch.

Visit the MDATP admin portal at https://securitycenter.microsoft.com/ and click the cog icon to change to the settings view.

Under General, Advanced Features enable Preview Features (whilst this feature is in preview, once it stops being a preview feature this step is no longer required).

On the same list of Advanced Features toggle the option for Web Content Filtering to enable the feature and click Save Preferences.

Enabling Web Content Filtering in MDATP Settings

In the option where you enable Web Content Filtering click the link to create a web content filtering policy to take you to the settings for this feature.

This opens a second tab but all it does it takes you to the Web Content Filtering node of the Settings page! Click + Add Item to start adding content filtering categories.

First, give the policy a name and click Next. Then choose a category or parent category. For example you could select the parent category Adult Content which will turn on seven categories, or you could select just a category such as Nudity. The parent categories are, in addition to Adult Content, High Bandwidth (with peer to peer, and streaming media sites included), Legal Liability (with categories such as child abuse, hacking, and criminal activity included), Leisure (including chat, games, and social networking as categories) and the blanket Uncategorized.

Blocked Categories page in MDATP Web Content Filtering policy creation

Click Next and then enable for all devices in your admin scope (so if you are Global Admin, that’s all devices!) or pick one or more device groups.

Roll Out Web Content Filtering To A Device Group

You need to have made the device groups in advance of setting up the policy, and this is available from the Settings page as well. In the above screenshot I have selected the UK device group which is a MDATP Tag set by the registry on all our UK machines. Create a pilot group tag and roll out this feature to a limited number of devices to test.

Click Next to get to the Summary page and then finish the policy creation.

Web Content Filtering Policies in MDATP

The policy you created and others if you have more than one are then shown.

There are no client agents to install for this feature to work – the MDATP sensor built into Windows 10 (1609 and later) does all the work. The website categories that are blocked are blocked in the browser with a warning. Blocks are performed by SmartScreen (Edge) and Network Protection (Chrome and Firefox). Network Protection is not a message in the browser though – it is a popup at the Operating System level. The Web Content Filter interrupts network traffic to the blocked sites, so Chrome and Firefox will show a network level error, and the OS popup will give the reason. Edge Browser integrates with the OS to show a proper error message (unless SmartScreen is disabled, in which case Network Protection will be the experience here in Edge as well).

Edge SmartScreen Block

In addition to the browser “requirement” for a nice error message, you also need to have the latest updates for Windows Defender signatures and platform, known as MoCAMP. An Advanced Hunting query on GitHub allows you to check the versions across your MDATP estate.

All viewed categories, blocked or not blocked, are reported back to MDATP via the telemetry – so you can create reports on the visited site categories even without blocking users. These reports are available from the MDATP portal and Reports > Web Protection:

Web Protection Report in MDATP

The above screenshot shows the only activity at the moment was Custom Indicators (see Blocking Apps With A Low Reputation) but as categories of web content and browsed they will appear on this report.

Web Categories As Shown On Day Web Content Filtering Was Turned On!

You can access the Report details for each card by selecting a table row or coloured bar from the chart in the card. The report details page for each card contains data about web content categories, website domains, and device groups.

If you create a Web Content Filtering Policy that has no blocked items in it, but apply this to all devices, you will get a report within a few days of the scope of all your users across all your devices (in MDATP that is) and the categories of URL they are visiting. Therefore, if you need to know what to block before you block it – create a policy that does not include any categories to block.

Categories
Advanced Threat Protection Application Guard ATP mdatp Office 365 ProPlus Safe Attachments Safe Documents windows 10

Office ATP Safe Documents

This is a new feature in Office 365 Advanced Threat Protection Plan 2 in addition to Safe Attachments. Safe Documents at the time of writing is only available in US based Office 365 tenants and only used by Office 365 ProPlus 2002 Monthly Channel (Targeted) builds (build 12527.20092) and later.

image

When a user receives an Office document from an external source the document is marked as such and can only be opened in “protected mode”. This stops editing and printing, but also (more importantly) stops macros and the like running as well. This reduction in functionality of editing and printing is enough for the user to often just take the document out of protected mode and impact your network.

When the document is emailed to the user, Office 365 ATP Safe Attachments (a Plan 1 feature) will process the document, but if the document is obtained another way, such as via a download link or copied onto a local file share, but is an externally sourced document, then the Safe Attachments vector of protection over email no longer applies.

This is where this new feature of Safe Documents comes into play. The entire document is uploaded to Microsoft’s datacentre and processed as if it where an attachment in email being processed via Safe Attachments.

An EU/UK datacentre version of this feature will come in due course.

What now happens is that the document is scanned in the cloud for “maliciousness” and the user is allowed to open the file and turn off  “protected mode” only if the document is considered safe. If the document is considered malicious then the user is not allowed to take the document out of “protected mode”.

This functionality was announced at Microsoft Ignite in November 2019 and is now in early preview at the time of writing this article. Future updates to this functionality will include the ability to open “protected mode” documents in a virtual machine automatically so that if the document does go rogue then closing the document results in closing the virtual machine and the removal of the impact, as all the changes were confined to the virtual machine. This feature is due Summer 2020 and is known as Application Guard for Office ProPlus. Application Guard will be included in subscriptions that include Windows 10 E5 (Windows 10 + Microsoft Defender Advanced Threat Protection).

More info: https://techcommunity.microsoft.com/t5/office-365-blog/new-functionality-to-make-it-easier-to-customize-manage-and/ba-p/1003047 and https://www.microsoft.com/security/blog/2020/02/12/building-on-secure-productivity/ and the documentation at https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/safe-docs

Categories
Authentication windows 10 windows 7

Outlook Authentication Broken–Username and Password Missing

I came across an issue recently where the Outlook security dialog box popup was broken. Rather than looking as below, the username and password fields where missing:

windows_security.jpg

The dialog box appeared as:

image

Notice that the username and password fields are missing! Also missing, and the key to this issue, is the picture is missing too. This is usually an empty box, but for some companies they use Group Policy to push out a different graphic.

That image is a bitmap stored in “C:\ProgramData\Microsoft\User Account Pictures”.

At a client of mine, the marketing department had requested the company logo replace the user picture and provided at 1MB file for this purpose. The file was deployed to all machines and overwrote the user.bmp by way of GPO preferences. Resizing user.bmp to under 48K in “C:\ProgramData\Microsoft\User Account Pictures\” on a single machine resolved the issue for users on that computer. We then changed the source of the image to under 48K centrally to fix all users.

Note that this was Windows 7 – different file sizes and dimensions exist for different versions of Windows. For example a user.bmp file on Windows 10 can be 448×448 and the default is just under 600KB. So again, the 1MB file mentioned above might also break Windows 10, but to fix the issue on that OS I probably dont need to reduce the file size so small.