When trying to scan an AWS instance with Nessus, you may encounter issues with authentication and scanning results. In this article, we will explore two approaches to scanning an AWS instance using Nessus, including troubleshooting common errors and potential solutions.

Approach 1: Scanning from Outside the VPC

The first approach is to scan the public IP of the AWS instance directly from your computer running Windows 10 with Nessus installed. This method may provide some basic information about the instance, but it will likely not return comprehensive results.

To scan an AWS instance using Nessus from outside the VPC, make sure that the security group associated with the instance allows inbound traffic from your home IP address. You can also try setting up a custom security rule to allow all inbound traffic from your IP address. However, even with these settings in place, you may still encounter issues with authentication and scanning results.

Approach 2: Scanning from Inside the VPC

The second approach is to run Nessus on an instance within the same VPC as the target instance. This method provides more flexibility and control over the scan process, but it also requires additional setup and configuration.

To scan an AWS instance using Nessus from inside the VPC, you can launch a Nessus BYOL AMI (Bring Your Own License) from the AWS Marketplace. Make sure to select the correct security group for the instance and configure the necessary network settings.

Once the Nessus instance is running, try scanning the target instance using the public IP address. You may encounter issues with authentication and scanning results, even if you have set up the security group correctly.

Troubleshooting Common Errors

When trying to scan an AWS instance with Nessus, you may encounter errors such as 'Instance 'has been turned off, crashed or became unreachable during the audit - scan was interrupted prior to completion.' To troubleshoot this error, try rebooting the scanner instance and re-running the scan.

Another common error is 'Authentication Success with Intermittent Failure,' which indicates that Nessus has successfully authenticated to the target instance but failed to complete the scan. This error may be caused by issues with network connectivity or security group settings.

In conclusion, scanning an AWS instance with Nessus can be a complex process, especially when trying to scan from outside the VPC or using the Nessus BYOL AMI. By understanding the common errors and potential solutions outlined in this article, you should be able to troubleshoot issues and successfully scan your AWS instances using Nessus.

Remember to check your security group settings, network connectivity, and IAM roles to ensure that your scanner instance has the necessary permissions to access and scan your target instance. With careful planning and configuration, you can use Nessus to scan your AWS instances effectively and efficiently.

How to use nessus on public ip