Forum Discussion
Microsoft purview endpoint DLP Printing
Hello All,
We can monitor print activities in Microsoft purview endpoint DLP, If someone print sensitive data based on the conditions defined in DLP it will take action on printing. I want to know how the Purview endpoint DLP intercepts the printing and avoid data exfiltration. Does it stop before it reaches the spooler?
Please provide technical insights on this doubt. Thank you.
Hi Shariff
Endpoint DLP intercepts print jobs at the application level before the content reaches the printer. Here's how it works technically.
The enforcement component is built into the Microsoft Defender for Endpoint sensor (the same agent handles both MDE and Endpoint DLP once devices are onboarded). It uses a combination of kernel-mode file system filter drivers and user-mode hooks to monitor file operations on the endpoint. When a user triggers a print action from any application, the DLP agent inspects the file content against your DLP policy conditions before the print data is rendered and sent to the spooler.
If the content matches a DLP rule configured to block printing, the job is stopped before it reaches the print spooler. The user sees a policy tip or block notification depending on your configuration (audit, block with override, or block). If the action is "block with override," the user gets a justification prompt and can proceed if they provide a reason.
A few technical details worth knowing:
The file classification happens when the file is created, modified, or first read after a policy change. Endpoint DLP evaluates the file against sensitive information types, sensitivity labels, or trainable classifiers at that point. So by the time a user hits print, the content has already been classified. The print enforcement is checking the existing classification against policy rules, not rescanning the full document content at print time.
For browser-based printing (Edge, Chrome with the Purview extension, Firefox with the Purview extension), the enforcement also intercepts before the data is sent to the printer. The DLP-aware browser extensions handle this for web content.
You can also scope printing enforcement using Printer Groups in your Endpoint DLP settings. This lets you allow specific printers (like corporate printers) while blocking everything else, or block all printing except authorized devices.
Reference:
- https://learn.microsoft.com/purview/endpoint-dlp-learn-about
Please mark as solution, if you find the answer helpful. This will assist others in the community who encounter a similar issue, enabling them to quickly find the solution and benefit from the guidance provided. 🖖
4 Replies
Hi Shariff
Endpoint DLP intercepts print jobs at the application level before the content reaches the printer. Here's how it works technically.
The enforcement component is built into the Microsoft Defender for Endpoint sensor (the same agent handles both MDE and Endpoint DLP once devices are onboarded). It uses a combination of kernel-mode file system filter drivers and user-mode hooks to monitor file operations on the endpoint. When a user triggers a print action from any application, the DLP agent inspects the file content against your DLP policy conditions before the print data is rendered and sent to the spooler.
If the content matches a DLP rule configured to block printing, the job is stopped before it reaches the print spooler. The user sees a policy tip or block notification depending on your configuration (audit, block with override, or block). If the action is "block with override," the user gets a justification prompt and can proceed if they provide a reason.
A few technical details worth knowing:
The file classification happens when the file is created, modified, or first read after a policy change. Endpoint DLP evaluates the file against sensitive information types, sensitivity labels, or trainable classifiers at that point. So by the time a user hits print, the content has already been classified. The print enforcement is checking the existing classification against policy rules, not rescanning the full document content at print time.
For browser-based printing (Edge, Chrome with the Purview extension, Firefox with the Purview extension), the enforcement also intercepts before the data is sent to the printer. The DLP-aware browser extensions handle this for web content.
You can also scope printing enforcement using Printer Groups in your Endpoint DLP settings. This lets you allow specific printers (like corporate printers) while blocking everything else, or block all printing except authorized devices.
Reference:
- https://learn.microsoft.com/purview/endpoint-dlp-learn-about
Please mark as solution, if you find the answer helpful. This will assist others in the community who encounter a similar issue, enabling them to quickly find the solution and benefit from the guidance provided. 🖖
Can I find the below verbiage not the exact one but with the same context in any Microsoft article, as I need that to justify.
Endpoint DLP intercepts print jobs at the application level before the content reaches the printer. Here's how it works technically.
The enforcement component is built into the Microsoft Defender for Endpoint sensor (the same agent handles both MDE and Endpoint DLP once devices are onboarded). It uses a combination of kernel-mode file system filter drivers and user-mode hooks to monitor file operations on the endpoint. When a user triggers a print action from any application, the DLP agent inspects the file content against your DLP policy conditions before the print data is rendered and sent to the spooler.
If the content matches a DLP rule configured to block printing, the job is stopped before it reaches the print spooler. The user sees a policy tip or block notification depending on your configuration (audit, block with override, or block). If the action is "block with override," the user gets a justification prompt and can proceed if they provide a reason.
As per the above statement it should trigger the notification as soon as user prints the sensitive information as defined in the DLP rule. However, for normal network printers and PDF printers, whenever I am printing I am getting block notification. However, the same thing is not happening with serverless printing platform that enables centralized management of direct IP printers. Have you seen any such issues ?
Thank you for the above reply, I just wanted to ask does below information is exactly available in any microsoft article as I could not spot the verbiage (Not exactly) but at least the concept you have mentioned.Endpoint DLP intercepts print jobs at the application level before the content reaches the printer. Here's how it works technically.
The enforcement component is built into the Microsoft Defender for Endpoint sensor (the same agent handles both MDE and Endpoint DLP once devices are onboarded). It uses a combination of kernel-mode file system filter drivers and user-mode hooks to monitor file operations on the endpoint. When a user triggers a print action from any application, the DLP agent inspects the file content against your DLP policy conditions before the print data is rendered and sent to the spooler.
well put Caleb. I second this answer. This is correct.
