Sensor Disconnected from the USM Anywhere Service

Role Availability Read-Only Investigator Analyst Manager

USM Anywhere Sensors sometimes disconnect from the USM Anywhere service (for example, during an update process). There is a process every hour to verify if the sensor Sensors are deployed into an on-premises, cloud, or multi-cloud environment to collect logs and other security-related data. This data is normalized and then securely forwarded to USM Anywhere for analysis and correlation. has been disconnected for 30 minutes or longer. When this happens, USM Anywhere informs users in a Manager role by email and generates an event. A new event is generated every 30 minutes until the sensor reconnects.

Warning: Currently, the Sensor Appears Offline and Sensor Reconnected events are generated at the same time as the regular events and system events. Soon, these events will be generated only as system events. See Regular Events and System Events, Orchestration Rule for the "Sensor Appears Offline" System Event, and Orchestration Rule for the "Sensor Reconnected" System Event for more information.

Events Main Page, Sensor Appears Offline Event

Note: Logs, including NXLog messages, are cached locally and will be forwarded to USM Anywhere when the connection resumes.

When a sensor disconnects from the USM Anywhere service, it sends an email notice within two hours to the email address you used to sign into USM Anywhere (as long as you are in a Manager role). This notice informs you that your sensor is not connected. You can immediately take action to restore your service either by working with LevelBlue Technical Support or by making an environmental, network connectivity change.

The notification will be generated daily until the sensor is reconnected. After seven days, the notifications will no longer be issued.

USM Anywhere checks every hour to verify whether the sensor has been reconnected. After your sensor reconnects, you receive an email notification informing you that your service has been restored. Because of this automated notification, you do not have to log in to the product to check the sensor connection status. USM Anywhere generates an event when a sensor reconnects.

Events Main Page, Sensor Reconnected Event

Important: If you are not receiving notifications of a disconnection, or your notifications are being sent outside of the expected window, that could indicate issues in your control node. See View Network Testing Information for instructions on how to verify your control node's connection.

Creating an Alarm Rule from These Events

Although USM Anywhere informs users in a Manager role by email when a sensor has been disconnected from the service and when the sensor has been reconnected, you can create an alarm rule to have more control when these events occur. The following activity is an example of how to create an alarm rule from the sensor offline event. You can do the same for the sensor reconnected event by entering reconnected in step 2.

To create an alarm rule from the Sensor Appears Offline event

  1. Go to Activity > Events.
  2. Enter offline in the Enter search phrase field.

    Offline Filter

  3. Click one of the events.
  4. Select Create Rule > Create Alarm Rule.

    Specific Event Dialog Box

    The Create Alarm Rule dialog box opens.

  5. Select a packet type in the Match drop-down list.

    Match Drop Down List

    The first match criteria for all rules must be the packet_type detail field:

  6. Click Add Conditions and select these properties values:

    Create Alarm Rule Dialog Box

  7. (Optional.) Click Add Group to group your conditions.

    Note: See Operators in the Orchestration Rules for more information.

  8. In the Occurrences text box, enter the number of event occurrences that you want to produce a match on the conditional expression to trigger the rule.

    You can enter the number of occurrences or use the arrows to scroll the value up or down. You can enter a number between 1 and 100.

  9. Click Next.
  10. Enter a name for the rule.
  11. (Optional.) Enter a description for identifying this rule.
  12. Select an intent.
  13. The intent describes the context of the behavior that is being observed. These intents roughly map to the stages of the intrusion kill chains but are collapsed to ensure that each is discrete. See Intent for more information about the available threat categories.

  14. Enter a method.
  15. If known, it is the method of attack or infiltration Indicator that specifies the method of attack that generated an alarm. For Open Threat Exchange® (OTX™) pulses, this method is the pulse name. associated with the indicator that generated the alarm.

    Note: This is a required field; if you do not complete this field, the Save button remains inactive.

  16. Select a strategy.
  17. The strategy describes the broad-based strategy or behavior that is detected. The intention is to describe the malicious Activity in a system that exceeds or misuses that access in a manner that negatively affects the confidentiality, integrity, or availability of the organization's information systems. user's strategy to achieve their goal.

  18. Enter a priority.
  19. See Priority Field for Alarms for more information.

  20. Configure a mute duration set in seconds, minutes, and hours.
  21. You can use the mute value to set the period of time during which, once an alarm is createdUSM Anywhere will not create a new alarm based on the same conditions.

    Note: Take care to set a mute duration that is long enough to cover the span of time in which matching events will occur to maximize the efficacy of your mute.

    Important: If your USM Anywhere™ is restarted when one of your alarm mutes is active, or if there is an update or hotfix, the alarm mute will be canceled.

  22. In the Length text box, specify the timespan that you want to use to identify a match for multiple occurrences. Enter the number in the text box, and then use the drop-down menu to select a value of seconds, minutes, or hours.

    This duration identifies the amount of time that transpires from the beginning to the end of the occurrence. If the number of occurrences is not met within this period, the rule is not a match.

  23. (Optional.) Select the fields that you want to display in the generated alarm.

    You can select or remove the fields you want to include in the details of the alarm. A field passes from one column to the other by clicking it.

  24. Click Save.

    The created rule displays in the list of rules. You can see it from Settings > Rules > Orchestration Rules. See Orchestration Rules for more information.