Use a custom log parser


Microsoft Defender for Cloud Apps is now part of Microsoft 365 Defender, which correlates signals from across the Microsoft Defender suite and provides incident-level detection, investigation, and powerful response capabilities. For more information, see Microsoft Defender for Cloud Apps in Microsoft 365 Defender.

Defender for Cloud Apps enables you to configure a custom parser to match and process the format of your logs so that they can be used for Cloud Discovery. Typically you would use a custom parser if the firewall or device is not explicitly supported by Defender for Cloud Apps. This can be a CSV parser or a custom key value parser.

The custom parser enables you to use logs from unsupported firewalls by following this process.

To configure a custom parser:

  1. In the Microsoft 365 Defender portal, under Cloud Apps, select Cloud Discovery. Then, in the top-right corner, select the Actions menu and select Create Cloud Discovery snapshot report.

    Create new snapshot report.

  2. Enter a Report name and a Description

  3. Under Source, select Custom log format....

    New snapshot report.

  4. Collect logs from your firewall and proxy, through which users in your organization access the Internet. Make sure to gather logs during times of peak traffic that are representative of all user activity in your organization.

  5. Open the logs you want to process in a text editor. Review their format, making sure that the column names in the log correspond to the fields in the Custom log format screen.

    Review field in custom log parser.

  6. Then, fill in the fields based on your data to delineate which columns in the data correlate to specific fields in Defender for Cloud Apps. You may have to modify column names in your log file to correlate properly.


    The fields are case-sensitive. Make sure you spell and type the names of the columns identically in Defender for Cloud Apps and in the log file. Also, make sure that the date format you choose is identical.

    Fill in custom log parser fields.

  7. Select Save. The custom log format your configured will be saved as the default custom parser. You can edit it at any time by clicking on Edit.

  8. Under Upload traffic logs, select the log file you modified and upload it. You can upload up to 20 files at once. Compressed and zipped files are also supported.

  9. Select Upload logs.

  10. After upload completes, the status message will appear at the top-right corner of your screen letting you know that your log was successfully uploaded.

  11. After you upload your log files, it will take some time for them to be parsed and analyzed. After processing of your log files completes, you'll receive an email to notify you that it's done.

  12. A notification banner will appear in the status bar at the top of the Cloud Discovery dashboard. The banner updates you with the processing status of your log files. processing log file menu bar.

  13. After the logs are uploaded successfully, you should see a notification letting you know that the log file processing completed successfully. At this point, you can view the report either by selecting the link in the status bar, or you can go Microsoft 365 Defender portal, select Settings. Then choose Cloud Apps, and then under Cloud Discovery, select Snapshot reports.

  14. Then select your snapshot report.

    snapshot report management.

Next steps

If you run into any problems, we're here to help. To get assistance or support for your product issue, please open a support ticket.