Click the icon, then select “Choose a virtual CD/DVD disk file” and browse to where you downloaded the Security Onion ISO file, select it then choose “Open.” Next click “Network” then “Adapter 2.” You’ll need to click the checkbox to enable it then attach it to “Internal Network.” Under the “Advanced” options, set “Promiscuous Mode” to “Allow All.” Click “Ok” and we are ready to install the operating system. To the right, you’ll see “CD/DVD Drive” with “IDE Secondary” specified with another CD icon. Click the “Storage” icon, then under “Controller: IDE” select the “Empty” CD icon. Mount the Security Onion ISO file so our VM can boot from it to install Linux.

Click “Create” and your Security Onion VM will be created.Īt this point, you can click “Settings” for your new virtual machine so we can get it configured. For disk size, you’ll want at least 200GB so you have enough capacity for retrieving/testing packet captures and downloading system updates. Once you’ve settled on the storage allocation, click “Continue” and provide a name from your hard disk image file and specify the location where you want the disk file to be created if other than the default location. If you happen to be running a dedicated sensor in a virtual machine, I would suggest using “Fixed size,” which will allocate all of the disk space you define up front and save you some disk performance early on. Specify “Create a virtual hard drive now” then click “Create” to choose the hard drive file type “VDI (VirtualBox Disk Image)” and “Continue.” For storage, we have the options of “Dynamically allocated” or “Fixed size.” For a client virtual machine, “Dynamically allocated” is the best choice as it will grow the hard disk up to whatever we define as the maximum size on an as needed basis until full, at which point Security Onion’s disk cleanup routines will work to keep disk space available.

Provide a name for the virtual machine (“Security Onion” for example) and specify the type (“Linux”) and version (this could be CentOS/RedHat or Ubuntu depending on which version you’re installing), then click “Continue.” We’ll next define how much memory we want to make available to our virtual machine based on the Hardware Requirements section.

First, launch VirtualBox and click the “New” button.

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