Spooky malware analysis!

It's October 31, so let's analyze some spooky malware!

Thanks to Brad Duncan for sharing this pcap from 2025-10-08 on his malware traffic analysis site! Due to issues with Google flagging a warning for the site, we're not including the actual hyperlink but it should be easy to find.

We did a quick analysis of this pcap using Security Onion 2.4.190:

https://blog.securityonion.net/2025/10/security-onion-24190-now-available.html

If you'd like to follow along, you can do the following:

• install Security Onion 2.4.190 in a VM:
  https://docs.securityonion.net/en/2.4/first-time-users.html
• import the pcap using the SOC Grid interface:
  https://docs.securityonion.net/en/2.4/grid.html#icons-in-lower-left-corner
• optionally enable the DNS lookups feature:
  https://docs.securityonion.net/en/2.4/soc-customization.html?#reverse-dns-lookups

The screenshots at the bottom of this post show some of the interesting alerts and their associated AI Summaries and Guided Analysis. Keep in mind that this is not some contrived demo, we simply downloaded a recent malware PCAP from Brad Duncan's site and imported it into Security Onion. Also keep in mind that this was just a PCAP and so there was no endpoint data. Had there been endpoint data, the results would have been even more in-depth.

Want more practice? Check out our other Quick Malware Analysis posts at:

https://blog.securityonion.net/search/label/quick%20malware%20analysis

About Security Onion

Security Onion is a versatile and scalable platform that can run on small virtual machines and can also scale up to the opposite end of the hardware spectrum to take advantage of extremely powerful server-class machines.  Security Onion can also scale horizontally, growing from a standalone single-machine deployment to a full distributed deployment with tens or hundreds of machines as dictated by your enterprise visibility needs. To learn more about Security Onion, please see:
https://securityonion.net

Screenshots

Let's start with an overview of all logs generated by Security Onion:

Now let's look at just the alerts sorted by severity:

Next we'll drill into the high severity alerts and review the AI Summaries and AI Playbooks:

Here's the second high severity alert:

And the third high severity alert:

And the fourth high severity alert:

All of the above can be done with our standard free version. 

Now let's look at our new Onion AI feature available for Security Onion Pro customers. First, we ask Onion AI to summarize the activity in the date range:

(Onion AI response continued):

We can then ask Onion AI to investigate the traffic to non-standard ports:

(Onion AI response continued):

Next, we ask Onion AI to investigate specific high severity alerts starting with the CnC Checkin alert:

(Onion AI response continued):

Finally, we ask Onion AI to investigate another high severity alert for a RAT SSL Cert:

(Onion AI response continued):

Additional analysis is left as an exercise to the reader!

Security Onion 2.4.190 now available including Onion AI Assistant for Pro Customers!

Security Onion 2.4.190 is now available and includes several new features, updated components, and many quality of life improvements! 

For Security Onion Pro customers, we've improved our hypervisor feature and added the new Onion AI Assistant!

Updated Components

This release updates several components including:

• ATT&CK Navigator
• ElastAlert
• Elastic Stack
• Golang
• Nginx
• Redis
• Telegraf
• Zeek
  
  

The Elastic and Redis updates resolve security issues so we highly recommend upgrading.

Security Onion Pro Feature: Hypervisor

In the recent 2.4.170 release, we added a new hypervisor feature for Security Onion Pro customers and then improved it in 2.4.180. This release continues to iterate on the Hypervisor feature making it even more powerful! For more information about the Hypervisor feature, please see:

https://docs.securityonion.net/en/2.4/hypervisor.html

Security Onion Pro Feature: Onion AI Assistant

Onion AI is a huge leap forward in leveraging AI to assist you in triaging alerts and working incidents!

https://docs.securityonion.net/en/2.4/assistant.html

Release Notes

There are many more features and fixes included in this release! For a complete list of all changes, please see the Release Notes:

https://docs.securityonion.net/en/2.4/release-notes.html#changes

Known Issues

For a list of known issues, please see:

https://docs.securityonion.net/en/2.4/release-notes.html#known-issues

About Security Onion

Security Onion is a free and open platform built by defenders for defenders. It includes network visibility, host visibility, intrusion detection honeypots, log management, and case management. 

For network visibility, we offer signature based detection via Suricata, rich protocol metadata and file extraction using your choice of either Zeek or Suricata, full packet capture, and file analysis. For host visibility, we offer the Elastic Agent which provides data collection, live queries via osquery, and centralized management using Elastic Fleet. Intrusion detection honeypots based on OpenCanary can be added to your deployment for even more enterprise visibility. All of these logs flow into Elasticsearch and we’ve built our own user interfaces for alerts, dashboards, threat hunting, case management, and grid management. 

Security Onion has been downloaded over 2 million times and is being used by security teams around the world to monitor and defend their enterprises. Our easy-to-use Setup wizard allows you to build a distributed grid for your enterprise in minutes!

Documentation

You can find our online documentation here:

https://docs.securityonion.net/en/2.4/

Documentation is always a work in progress. If you find documentation that needs to be updated, please let us know as described in the Feedback section below.

New Installations

If this is your first time installing Security Onion 2.4, then we highly recommend starting with an IMPORT installation as shown at:

https://docs.securityonion.net/en/2.4/first-time-users.html

Once you’re comfortable with your IMPORT installation, then you can move on to more advanced installations as shown at:

https://docs.securityonion.net/en/2.4/architecture.html

Existing 2.4 Installations

If you have an existing Security Onion 2.4 installation, you can update to the latest version using soup:

https://docs.securityonion.net/en/2.4/soup.html

Before updating your production deployment, we highly recommend testing the upgrade process on a test deployment that closely matches your production deployment if possible. This is especially important for releases that update components like Salt and Elastic.

2.3 EOL

As a reminder, Security Onion 2.3 reached End Of Life (EOL) on April 6, 2024:

https://blog.securityonion.net/2023/10/6-month-eol-notice-for-security-onion-23.html

Thanks

Lots of love went into this release!

Special thanks to all our folks working so hard to make this release happen!

• Josh Brower
• Jason Ertel
• Corey Ogburn
• Josh Patterson
• Mike Reeves
• Jorge Reyes
• Matthew Wright

Questions, Problems, and Feedback

If you have any questions or problems, please create a new Discussion at:

https://securityonion.net/discuss

Security Onion Pro

We recently celebrated 10 years in business by announcing Security Onion Pro:

https://blog.securityonion.net/2024/07/celebrating-10-years-of-security-onion.html

Security Onion Pro includes many enterprise features that folks have been asking for:

• Active Query Management
• External API
• Open ID Connect (OIDC)
• Data at Rest Encryption
• FIPS for the OS
• DoD STIG for the OS
• External Notifications in SOC
• Time Tracking inside of Cases
• Guaranteed Message Delivery
• Manager of Managers
• MCP Server
• Security Onion App for Splunk
• Hypervisor
• Reports
• Onion AI Assistant

You can read more about these enterprise features at:

https://securityonion.com/pro

Training

Need training? Start with our free Security Onion Essentials training and then take a look at some of our other official Security Onion training!

https://securityonion.net/training

Security Onion Solutions Hardware Appliances

We know Security Onion's hardware needs, and our appliances are the perfect match for the platform. Leave the hardware research, testing, and support to us, so you can focus on what's important for your organization. Not only will you have confidence that your Security Onion deployment is running on the best-suited hardware, you will also be supporting future development and maintenance of the Security Onion project!

https://securityonion.com/hardware

Cloud Installations

For new Security Onion 2 installations in the cloud, this new version will soon be available on the AWS, Azure, and GCP marketplaces!

AWS Marketplace and Documentation:

https://securityonion.net/aws/?ref=_ptnr_soc_blog_250917

https://docs.securityonion.net/en/2.4/cloud-amazon.html

Azure Marketplace and documentation:

https://securityonion.net/azure

https://docs.securityonion.net/en/2.4/cloud-azure.html

GCP Marketplace and documentation:

https://securityonion.net/google

https://docs.securityonion.net/en/2.4/cloud-google.html