This document and accompanying video will demonstrate how to network contain (quarantine) an endpoint with Falcon Endpoint Protection. When systems are contained, they will lose the ability to make network connections to anything other than the CrowdStrike cloud infrastructure and any internal IP addresses that have been specified in the Respond App.
A Windows 7 SP1 or higher system with the Falcon sensor installed.
Identify and contain a compromised system
In the Falcon UI, navigate to the Detections App. Often times, network containment is necessary when a system appears infected and lateral movement, persistence and exfiltration want to be prevented, among other risks.
In our Activity App, we see a system that has multiple detections in a short amount of time, and it can quickly be ascertained that action should be taken. To get more detail, select any of the lines where an alert is indicated. Doing so will provide more details and allow you to take immediate action.
After drilling into the alert, we can see multiple detection patterns, including known malware, credential theft and web exploit. Drilling into the process tree, we can see that reconnaissance was performed and credential theft occured, possibly in an attempt for lateral movement.
To prevent this movement and contain this system from the network, select the “Network Contain this machine” option near the top of the page.
Selecting the “Network Contain” will open a dialogue box with a summary of the changes you are about to make and an area to add comments.
After information is entered, select Confirm. The dialogue box will close and take you back to the previous detections window. To verify that the host has been contained select the hosts icon next to the Network Contain button.
The Hosts app will open to verify that the host is either in progress or has been contained. Containment should be complete within a few seconds. If containment is pending the system may currently be off line.
Removing a system from Network Contain
After investigation and remediation of the potential threat, it is easy to bring the device back online. Since a connection between the Falcon Sensor and the Cloud are still permitted, “un-contain” is accomplished through the Falcon UI.
In the UI, navigate to the Hosts app. Locate the contained host or filter hosts based on “Contained” at the top of the screen. Once the host is selected you’ll see that the status is contained (see previous screenshot) and click on the “Status: Contained” button.
Make any comments and select “Confirm”. The previous status will change from “Lift Containment Pending” to “Normal” (a refresh may be required). Again if the change doesn’t happen within a few seconds the host may be off line.
Network containment is a fast and powerful tool that is designed to give the security admin the power needed to identify threats and stop them. For more information on Falcon, see the additional resources and links below.
- CrowdStrike Tech Center
- Sign up for a weekly Falcon demo
- Request a 1:1 Demo
- Guide to AV Replacement
- Falcon OverWatch
How to Contain an Infected System
Hi, there. My name’s Peter Ingebrigtsen. And today, we’ve logged into the falcon.crowdstrike.com, or the Falcon User Interface.
And what we’re going to do is take a look at some of our systems and recognize that some of them are either currently under attack or recently been under attack, and may have been compromised. And we’d like to contain that system until we can further get to it, get our hands on it, and get a little bit more information out of it, or just prevent it from doing any more damage than it’s already done.
In order to do that, you need to be on your Detections app. You can do that by going to the radar here on the left-hand side. If you’re not already, or if your user interface doesn’t open that when you first log in, head there. And then just select the Recent Detections.
When that opens, you’ll notice that you can filter by any number of criteria, but we’re looking at some of the more recent events or situations that are going on. And you’ll notice that the same single machine has noticed a lot of different scenarios with privilege escalation or web exploits. And these severities are high to critical.
And we’d like to log in there, maybe do a little something, take a little closer look, and see if there’s something we should do. Obviously, we should do something. And as we start to dig through here, we see that there’s a lot of detection patterns, whether that be known malware, credential theft, or web exploits. We can see in the process tree a lot of different commands that were issued that look at that privilege escalation that we noticed earlier– or start to set that up.
So, we know that there’s something bad going on, and we’d like to take action right away. So, what we want to do is network contain this machine. But what I want to show you, as well, is that as we do this– I’m going to go to the machine itself. And I’d like to start a continuous ping so that you can watch the behavior and how long it takes to respond to this network containment.
Now, while we contain this– or take this machine off the network– we don’t kill the connection to the CrowdStrike Cloud. So, that as we get our hands on it– we clean it up, we feel comfortable putting it back on to the network– we can still operate or control that machine through the user interface that we have here.
The other thing I’d like to do is start a large download, so that we initiate with a single TCP connection– and there happens to be one in process– as opposed to the ping, where there may be multiple TCP resets or individual TCP threads going every time. So that you can see that as we contain this machine, it literally just knocks it off the network.
Forgive my screen, but I’ve changed the resolution for YouTube and for appearance purposes.
But as I come in here– and this will be right at the middle of the screen– this actually says Device Actions. And I’d like to contain it.
Now, as we do that, we have some options to make some notes. Contained by Peter. Multiple threats observed. Whatever notes you’d like to make– and then select Contain.
Now, the second we do this, on the left-hand side, you’ll see how quickly it takes for that to respond. So, immediately, almost in real time, you see a network failure on the download, and the ping test– or the continuous ping fail. So, we can close that.
Now, let’s say we’re a couple days later, this machine’s cleaned up, ready to go, and be put back in the network. You can go ahead and lift the network containment, again, from the user interface. We still have that connection to the machine, even though all the other network connections have been terminated.
So, as we do that, all good. Uncontain. And you’ll notice that almost immediately that ping starts to fire right back up again.
So, network containment is a powerful tool that we can use if we see something immediately taking action or if we see something recently in the past, and we’d like to get that machine off the network– almost quarantine it– so that it can’t do any more damage.
So, this has been network containment of network devices in the Falcon Sensor User Interface platform. Thanks again for watching.