Atomic Red Team is an excellent collection of commands, activities, and other Indicators of Compromise (IoCs) developed and maintained by Red Canary that your blue team can benchmark against to hone their craft. We’ve loved using the Atomic tests as a reference and have developed a GUI-based execution engine to run through them automatically on Windows. This blog covers installation and execution of our Atomic Red Team execution engine. You can find more details on Atomic Red Team and the Atomic tests at https://atomicredteam.io/.

To get the execution engine go to: https://github.com/tevora-threat/atomic_red_team_gui.

Atomic Red Team Overview

The Atomic Red Team project, https://atomicredteam.io/, is an open source collection of behavior definitions mapping to the MITRE ATT&CK framework maintained by Red Canary. Red Canary describes them as "Our Atomic Red Team tests are small, highly portable detection tests mapped to the MITRE ATT&CK Framework. Each test is designed to map back to a particular tactic. This gives defenders a highly actionable way to immediately start testing their defenses against a broad spectrum of attacks."

These can be used to generate Indicators of Compromise (IoCs) and to test the ability to detect and respond to them.

Tevora Execution Engine

Tevora developed an execution engine for attack definitions in the Atomic Red Team project that allows for automated running and reporting of the attacks defined therein on Windows systems. The execution engine runs through these attacks and generates a test plan and report based on the ingested and ran Atomics. This allows for running through all Atomics automatically and basic logging of the performed activity.

Tevora's built a simple GUI around this execution engine to make running and reporting thes Atomics on Windows systems relatively simple.

Installation

The Tevora Atomic Red Team execution engine needs two components:

1. The folder of Atomic definitions

2. The Tevora Execution Engine Executable

In order to run the red team simulation, the Execution Engine exe must be opened, and then configured to point at the directory in which the Atomic definitions are stored as enumerated below:

Installation Steps:

1. Open the .sln file in visual studio and compile the exe

2. Download the atomics you wish to run from: https://github.com/redcanaryco/atomic-red-team/tree/master/atomics

3. Select a system to run the tests on.

a. Tevora recommends running the test on a standard newly provisioned employee workstation with normal EDR/AV software installed in detect only mode

i. If AV is deployed in block mode, it may interfere with being able to run the execution engine, Tevora recommends running in detect mode to see what would have been blocked without causing issues running the test.

b. If possible, Tevora recommends running in a VM, taking a snapshot prior to running the execution engine for easy reversion.

c. Some atomics are destructive, in that they add things such as registry autoruns without cleaning up, thus reverting from a snapshot is an easy way to ensure the test is run on a clean platform each time

d. For this same reason, Tevora recommends not running this tool on production systems unless careful tuning and removal of destructive atomics is done, or if only single or few atomics that are known to not modify the system are run.

4. Extract the zip folder to a location of your choosing.

5. The atomic red team execution engine is now ready to be run.

Execution

1. Open the compiled redsim .exe file

2. Select "Load Atomics" from the bottom right context menu

3. Navigate to the unzipped directory and open the atomics folder, or select a customized folder of atomics.

a. At this point the Atomic Red Team Execution Engine GUI should populate with the loaded atomics

4. The red team execution engine will output results of its runs, to select where these will be saved to, select the "Output Directory" output and select a folder

5. (optional) If you want to export a plan of what commands are going to be run, select "Export Test Plan" from the bottom right menu. This will be saved to the "Output Directory" location.

6. After reviewing the loaded atomics, and confirming the test plan, click "Execute Atomics"

a. The tests are now executing and the progress bar at the bottom will record whatis currently executing and how many remain.

b. As each test is ran, the execution engine will log the results to a csv file timestamped on when each IOC occurred.

7. Once testing has completed, review the csv of the test log in the output folder.

Review

ter running the automated simulation, many IoCs should have been gen-erated. Review the results from your SOC, EDR solution, SIEM, and other security monitoring tools to understand what was caught and what was not. The CSV output file should contain sufficient detail, including the date and time each command was performed, to cross reference with security alerts or logs.

A key element of this process is to identify areas that were NOT caught by the automated simulation, and to drill down to understand why. Ultimately, the goal of running this simulation is to identify areas of weakness in your security monitoring program and improve them. Once you’ve identified ar-eas that were NOT detected, remediation should be performed to ensure they will be detected and tests should be re-run to confirm that they are detected.

Although the automated red team sim is a great tool to assess the state of current detection capabilities and to improve them, it is important to not limit your security detection and response program to one that only uses the defined Atomic Red Team simulations. You should perform periodic manual red teaming and IOC generation to assess new risks and to ad-dress a changing threat posture. Additionally, Tevora recommends peri-odically reviewing and updating IoCs to reflect current threat actors.