Set preferences for Microsoft Defender for Endpoint on Linux

In enterprise environments, Defender for Endpoint on Linux can be managed through a configuration profile. This profile is deployed from the management tool of your choice. Preferences managed by the enterprise take precedence over the ones set locally on the device. In other words, users in your enterprise are not able to change preferences that are set through this configuration profile.

This article describes the structure of this profile (including a recommended profile that you can use to get started) and instructions on how to deploy the profile.

Configuration profile structure

The configuration profile is a .json file that consists of entries identified by a key (which denotes the name of the preference), followed by a value, which depends on the nature of the preference. Values can be simple, such as a numerical value, or complex, such as a nested list of preferences.

Typically, you would use a configuration management tool to push a file with the name mdatp_managed.json at the location /etc/opt/microsoft/mdatp/managed/.

The top level of the configuration profile includes product-wide preferences and entries for subareas of the product, which are explained in more detail in the next sections.

Antivirus engine preferences

The antivirusEngine section of the configuration profile is used to manage the preferences of the antivirus component of the product.

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Enable / disable real-time protection

Determines whether real-time protection (scan files as they are accessed) is enabled.

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Enable / disable passive mode

Determines whether the antivirus engine runs in passive mode or not. In passive mode:

• Real-time protection is turned off.
• On-demand scanning is turned on.
• Automatic threat remediation is turned off.
• Security intelligence updates are turned on.
• Status menu icon is hidden.

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Enable/disable behavior-monitoring

Determines whether behavior monitoring and blocking capability is enabled on the device or not. To improve effectiveness of security protection, we recommend keeping this feature turned on.

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Run a scan after definitions are updated

Specifies whether to start a process scan after new security intelligence updates are downloaded on the device. Enabling this setting will trigger an antivirus scan on the running processes of the device.

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Scan archives (on-demand antivirus scans only)

Specifies whether to scan archives during on-demand antivirus scans.

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Degree of parallelism for on-demand scans

Specifies the degree of parallelism for on-demand scans. This corresponds to the number of threads used to perform the scan and impacts the CPU usage, as well as the duration of the on-demand scan.

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Exclusion merge policy

Specifies the merge policy for exclusions. It can be a combination of administrator-defined and user-defined exclusions (merge) or only administrator-defined exclusions (admin_only). This setting can be used to restrict local users from defining their own exclusions.

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Scan exclusions

Entities that have been excluded from the scan. Exclusions can be specified by full paths, extensions, or file names. (Exclusions are specified as an array of items, administrator can specify as many elements as necessary, in any order.)

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Type of exclusion

Specifies the type of content excluded from the scan.

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Path to excluded content

Used to exclude content from the scan by full file path.

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Path type (file / directory)

Indicates if the path property refers to a file or directory.

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File extension excluded from the scan

Used to exclude content from the scan by file extension.

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Process excluded from the scan*

Specifies a process for which all file activity is excluded from scanning. The process can be specified either by its name (for example, cat) or full path (for example, /bin/cat).

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Allowed threats

List of threats (identified by their name) that are not blocked by the product and are instead allowed to run.

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Disallowed threat actions

Restricts the actions that the local user of a device can take when threats are detected. The actions included in this list are not displayed in the user interface.

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Threat type settings

The threatTypeSettings preference in the antivirus engine is used to control how certain threat types are handled by the product.

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Threat type

Type of threat for which the behavior is configured.

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Action to take

Action to take when coming across a threat of the type specified in the preceding section. Can be:

• Audit: The device is not protected against this type of threat, but an entry about the threat is logged.
• Block: The device is protected against this type of threat and you are notified in the security console.
• Off: The device is not protected against this type of threat and nothing is logged.

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Threat type settings merge policy

Specifies the merge policy for threat type settings. This can be a combination of administrator-defined and user-defined settings (merge) or only administrator-defined settings (admin_only). This setting can be used to restrict local users from defining their own settings for different threat types.

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Antivirus scan history retention (in days)

Specify the number of days that results are retained in the scan history on the device. Old scan results are removed from the history. Old quarantined files that are also removed from the disk.

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Maximum number of items in the antivirus scan history

Specify the maximum number of entries to keep in the scan history. Entries include all on-demand scans performed in the past and all antivirus detections.

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Cloud-delivered protection preferences

The cloudService entry in the configuration profile is used to configure the cloud-driven protection feature of the product.

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Enable / disable cloud delivered protection

Determines whether cloud-delivered protection is enabled on the device or not. To improve the security of your services, we recommend keeping this feature turned on.

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Diagnostic collection level

Diagnostic data is used to keep Defender for Endpoint secure and up-to-date, detect, diagnose and fix problems, and also make product improvements. This setting determines the level of diagnostics sent by the product to Microsoft.

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Enable / disable automatic sample submissions

Determines whether suspicious samples (that are likely to contain threats) are sent to Microsoft. There are three levels for controlling sample submission:

• None: no suspicious samples are submitted to Microsoft.
• Safe: only suspicious samples that do not contain personally identifiable information (PII) are submitted automatically. This is the default value for this setting.
• All: all suspicious samples are submitted to Microsoft.

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Enable / disable automatic security intelligence updates

Determines whether security intelligence updates are installed automatically:

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Recommended configuration profile

To get started, we recommend the following configuration profile for your enterprise to take advantage of all protection features that Defender for Endpoint provides.

The following configuration profile will:

• Enable real-time protection (RTP)
• Specify how the following threat types are handled:
  • Potentially unwanted applications (PUA) are blocked
  • Archive bombs (file with a high compression rate) are audited to the product logs
• Enable automatic security intelligence updates
• Enable cloud-delivered protection
• Enable automatic sample submission at safe level
• Enable behavior-monitoring

Sample profile

{
   "antivirusEngine":{
      "behaviorMonitoring":"enabled",
      "enableRealTimeProtection":true,
      "threatTypeSettings":[
         {
            "key":"potentially_unwanted_application",
            "value":"block"
         },
         {
            "key":"archive_bomb",
            "value":"audit"
         }
      ]
   },
   "cloudService":{
      "automaticDefinitionUpdateEnabled":true,
      "automaticSampleSubmissionConsent":"safe",
      "enabled":true,
      "proxy":"http://proxy.server:port/"
   }
}

Full configuration profile example

The following configuration profile contains entries for all settings described in this document and can be used for more advanced scenarios where you want more control over the product.

Full profile

{
   "antivirusEngine":{
      "behaviorMonitoring":"enabled",
      "enableRealTimeProtection":true,
      "scanAfterDefinitionUpdate":true,
      "scanArchives":true,
      "maximumOnDemandScanThreads":2,
      "passiveMode":false,
      "exclusionsMergePolicy":"merge",
      "exclusions":[
         {
            "$type":"excludedPath",
            "isDirectory":false,
            "path":"/var/log/system.log"
         },
         {
            "$type":"excludedPath",
            "isDirectory":true,
            "path":"/run"
         },
         {
            "$type":"excludedPath",
            "isDirectory":true,
            "path":"/home/*/git"
         },
         {
            "$type":"excludedFileExtension",
            "extension":".pdf"
         },
         {
            "$type":"excludedFileName",
            "name":"cat"
         }
      ],
      "allowedThreats":[
         "<EXAMPLE DO NOT USE>EICAR-Test-File (not a virus)"
      ],
      "disallowedThreatActions":[
         "allow",
         "restore"
      ],
      "threatTypeSettingsMergePolicy":"merge",
      "threatTypeSettings":[
         {
            "key":"potentially_unwanted_application",
            "value":"block"
         },
         {
            "key":"archive_bomb",
            "value":"audit"
         }
      ]
   },
   "cloudService":{
      "enabled":true,
      "diagnosticLevel":"optional",
      "automaticSampleSubmissionConsent":"safe",
      "automaticDefinitionUpdateEnabled":true,
      "proxy": "http://proxy.server:port/"
   }
}

Add tag or group ID to the configuration profile

When you run the mdatp health command for the first time, the value for the tag and group ID will be blank. To add tag or group ID to the mdatp_managed.json file, follow the below steps:

1. Open the configuration profile from the path /etc/opt/microsoft/mdatp/managed/mdatp_managed.json.
2. Go down to the bottom of the file, where the cloudService block is located.
3. Add the required tag or group ID as following example at the end of the closing curly bracket for the cloudService.

  },
   "cloudService":{
      "enabled":true,
      "diagnosticLevel":"optional",
      "automaticSampleSubmissionConsent":"safe",
      "automaticDefinitionUpdateEnabled":true,
      "proxy": "http://proxy.server:port/"
   },
   "edr":{
        "groupIds":"GroupIdExample",
        "tags":"MDETagExample"
        }
}

Configuration profile validation

The configuration profile must be a valid JSON-formatted file. There are a number of tools that can be used to verify this. For example, if you have python installed on your device:

python -m json.tool mdatp_managed.json

If the JSON is well-formed, the above command outputs it back to the Terminal and returns an exit code of 0. Otherwise, an error that describes the issue is displayed and the command returns an exit code of 1.

Verifying that the mdatp_managed.json file is working as expected

To verify that your /etc/opt/microsoft/mdatp/managed/mdatp_managed.json is working properly, you should see “[managed]” next to these settings:

• cloud_enabled
• cloud_automatic_sample_submission_consent
• passive_mode_enabled
• real_time_protection_enabled
• automatic_definition_update_enabled

Configuration profile deployment

Once you’ve built the configuration profile for your enterprise, you can deploy it through the management tool that your enterprise is using. Defender for Endpoint on Linux reads the managed configuration from the /etc/opt/microsoft/mdatp/managed/mdatp_managed.json file.

Source : Official Microsoft Brand
Editor by : BEST Antivirus KBS Team