Application Resilience policies for Tenable Nessus Agent

Application Resilience policies for Tenable Nessus Agent are supported on devices running:

• a supported version of the Windows operating system

• PowerShell version 5.1 or higher

  Due to PowerShell restrictions imposed by Microsoft, Application Resilience isn't supported for this application on devices running Windows 11 SE.

• one of the following versions of Tenable Nessus Agent:

  • 8.x or higher

    Significant software changes in higher versions may cause health checks to become invalid.

In addition to checking the version, the following table describes the health checks performed:

If you select Report higher versions as Compliant, higher versions report Compliant without running health checks.

Component	Test performed
Services	Installed	Running	Signed by
Tenable Nessus Agent (nessus-service.exe)	P	P	One of the signers entered in the policy configuration By default, Signers contains "Tenable Inc." and "TENABLE, INC.".

You can configure an Application Resilience policy for Tenable Nessus Agent to enable the Application Resilience (RAR) component A lightweight software component of the Secure Endpoint Agent that detects the status of third party applications installed on a device. The component may also attempt to repair the third party application if it is non-compliant. The RAR component is deployed on a device only when the device is associated with a customized policy group and that policy group's Application Resilience policy is activated. to attempt to repair Tenable Nessus Agent if it's not functioning, or reinstall it if it's missing or can't be repaired.

Depending on the Absolute product licenses associated with your account, the Report and repair option, and the Report, repair, and reinstall option may not be available.

The RAR component of the Secure Endpoint Agent can respond to the following issues:

Issue	Resolution
Repair
The Tenable Nessus Agent (nessus-service.exe) service isn't running	The RAR component restarts the service.
The Tenable Nessus Agent (nessus-service.exe) service isn't installed and the service's executable can be detected on the device	The RAR component reinstalls the missing service.
Reinstall
Downgrades are not supported. If the version installed on a device is higher than the expected version, no action is taken.
The Tenable Nessus Agent (nessus-service.exe) service isn't installed and the service's executable cannot be detected on the device	The RAR component downloads and installs the configured version of the application.
Tenable Nessus Agent failed to be repaired, or the expected version isn't installed

You can add a 32-bit installer, a 64-bit installer, or both. The installers:

• must be MSI files

• can have any file name

Before you activate an Application Resilience policy you need to configure the policy. You need to configure the application version in addition to the settings in Configuring Application Resilience policies.

To configure the application version:

Under Tenable Nessus Agent version, enter the version of Tenable Nessus Agent you expect to be running on your devices.

• The target version must be a sequence of digits separated by a period.
• You can use wildcard "*" characters after the major version number, for example, 8.*, 8.2.*, or 10.6.1.*.

Make sure the version you are entering is consistent with version 8.x or higher.

If you selected the Report, repair, and reinstall option, you also need to configure these settings in addition to the settings in Configuring Application Resilience policies.

To configure the Tenable Nessus Agent specific settings:

For information on the following Tenable Nessus Agent settings, see the Tenable Nessus Agent documentation.

1. Under Nessus Agent Linking Key, enter the Nessus Agent Linking Key with the value obtained from the manager.
2. Under Server, enter the Nessus Server address with the value obtained from the manager. Use one of the following URL formats:
   • IP:PORT
   • HOST:PORT
   • [IPV6]:PORT

3. [Optional] Under Groups, enter all existing agent groups where you want to add the agent. Enter multiple groups in a comma separated list. Don't use quotation marks around each group. For example, Group1, Group2.

   If you don't specify any agent groups here, you can add your linked agent to an agent group later using the manager.

4. [Optional] Under Additional installer commands, enter the applicable command-line parameters to configure any settings not covered by the policy configuration.