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Continuous Atomic Testing

Carrie Roberts edited this page Oct 4, 2023 · 33 revisions

The Atomic Runner functionality allows you to run a configurable list of atomic tests unattended in a way that aids prevention and detection reporting. The scripts are designed to run all the tests you have listed in the CSV schedule once per week by default. Before it runs each atomic test it appends the atomic test GUID to the end of the computer hostname. This makes it easier to determine which detections fired from which atomics because the hostname in the detection will include the GUID of the atomic test that was running at the time. The cleanup commands are run after atomic test execution as well.

This script works for Windows, Linux and macOS. You need to have PowerShell Core installed on Linux/macOS to use these scripts

Setup and Configuration

Install Atomic Red Team and Invoke-AtomicRedTeam

IEX (IWR 'https://raw.githubusercontent.com/redcanaryco/invoke-atomicredteam/master/install-atomicredteam.ps1' -UseBasicParsing);
Install-AtomicRedTeam -getAtomics -Force -noPayloads

Note (Windows Only): Your Local Security Policy (Security Settings -> Local Polices -> Security Option) "Network Access: Do not allow storage of passwords and credentials for network authentication" must be disabled on your Atomic Runner to allow the scheduled task to be created.

Set Custom Config using privateConfig.ps1

There is a config file called config.ps1 in the <installFolder>\Invoke-AtomicRedTeam\Public folder. You can optionally modify any of the default values in this config file by creating a file called privateConfig.ps1 in the <installFolder>.

Configuration Variable Description
PathToInvokeFolder The folder containing the installed Invoke-AtomicRedTeam folder
PathToPublicAtomicsFolder The folder containing the installed atomics folder
PathToPrivateAtomics The folder containing your own private atomics (if any)
user The user/account that will be used to execute atomics
basePath The path where you want the folder created that houses the logs and the runner schedule.
scheduleTimeSpan The time span in which you want all of the atomics on your schedule to complete.
scheduleFileName The name of the csv file containing the schedule (list) of atomic tests to run.
kickOffDelay A delay (specified as a PowerShell Timespan object) to sleep before running the atomic
syslogServer Set this to the name of your syslog server if you want to use the SysLog execution logger
syslogPort The port for the syslog server (ignored if syslogServer not set)
syslogProtocol The port for the network protocol to use with the syslog server (options are UDP, TCP, TCPwithTLS)
LoggingModule The logging module to use for the atomic execution logs (e.g. Attire-ExecutionLogger, Syslog-ExecutionLogger or WinEvent-ExecutionLogger
verbose Set to $true for more output in the runner logs
debug Set to $true for additional output which will be added to a file called all-out-<base hostname>.txt
logFolder Name of the folder that will be found in the basePath and contains the Runner logs
CustomTag A string that you want sent with each execution log sent to the SysLog logger
absb An optional AMSI bypass script block that will be run before each atomic (Windows Only)
gmsaAccount A group managed service account to use for renaming the host if required (Windows Only)

Table of default values:

config variable default (Windows) default (Linux/macOS)
PathToInvokeFolder C:\AtomicRedTeam\Invoke-AtomicRedTeam ~/AtomicRedTeam/Invoke-AtomicRedTeam
PathToPublicAtomicsFolder C:\AtomicRedTeam\atomics ~/AtomicRedTeam/atomics
PathToPrivateAtomics C:\PrivateAtomics\atomics ~/PrivateAtomics/atomics
user $env:USERDOMAIN\$env:USERNAME $env:USER
basePath $env:HOME $env:USERPROFILE
scheduleTimeSpan 7 days 7 days
scheduleFileName AtomicRunnerSchedule.csv AtomicRunnerSchedule.csv
kickOffDelay 0 minutes 0 minutes
syslogServer
syslogPort 514 514
syslogProtocol UDP UDP
LoggingModule Default-ExecutionLogger Default-ExecutionLogger
verbose $false $false
debug $false $false
logFolder AtomicRunner-Logs AtomicRunner-Logs
CustomTag
absb $null $null
gmsaAccount $null $null

Example privateConfig.ps1

$artConfig | Add-Member -Force -NotePropertyMembers @{
  PathToPrivateAtomics = "C:\MyPrivateAtomics\atomics"
  scheduleTimeSpan = New-TimeSpan -Days 1 
  verbose = $true
  LoggingModule = "WinEvent-ExecutionLogger"
}

Note: You must start a new PowerShell window for any changes to the privateConfig file to take effect.

Run Invoke-SetupAtomicRunner

# Run Invoke-SetupAtomicRunner as the runner user (from admin prompt)
Invoke-SetupAtomicRunner

Note: On Windows, you will be prompted to enter the credentials of the user that will be running the atomics.

The setup script does the following:

  1. If you configured a group managed service account (gMSA) for renaming the computer, a JEA endpoint will be created for renaming the computer using the gMSA account.
  2. Creates a scheduled task called KickOff-AtomicRunner to keep the Runner running after a restart (or a cron job on Linux/macOS)
  3. Adds an Import-Module statement to your PowerShell profile to load Invoke-AtomicRedTeam.psd1 automatically
  4. Installs the Posh-SYSLOG module it is missing and you are configured to use it.
  5. Creates a CSV schedule file listing all of the atomics in your atomics folders (public and private). All atomics will be disabled by default.
  6. Runs the get_prereqs commands for all atomic tests that are enabled (active) on the schedule.

Enable Atomic Tests on the Schedule File

Edit the schedule file to enable some atomics to run (these will all run every X minutes as calculated using the scheduleTimeSpan and the number of atomic tests enabled on your schedule). By default, the schedule will be located at \AtomicRunner\AtomcRunnerSchedule.csv

Example AtomicRunnerSchedule.csv files are found here.

Run Invoke-SetupAtomicRunner (again)

Run Invoke-SetupAtomicRunner (again) to get any prereqs for tests that you enabled on the schedule.

Restart the computer to kickoff the Atomic Runner process

The KickOff-AtomicRunner Scheduled Task

The KickOff-AtomicRunner scheduled task (or cronjob on Linux/macOS) calls the Invoke-AtomicRunner function after the computer restarts. It runs 1 minutes after reboot (with retries at 2,4,8,16,32 and 64 minutes if needed - Windows only). The KickOff-AtomicRunner script also handles log rotation for the Runner scripts.

The Invoke-AtomicRunner Function

The Invoke-AtomicRunner function does the following:

  1. Parses the Atomic GUID from the end of the computer hostname to know which atomic test it should run. If no GUID is found, it assumes it should run first atomic test enabled on the schedule.
  2. Executes the atomic test specified by the GUID
  3. Sleeps for an amount of time calculated by the scheduleTimeSpan and the number of atomic tests enabled on the schedule
  4. Runs the cleanup commands for the atomic
  5. Renames the computer to include the GUID of the next enabled test on the schedule

Runner Logs

Additional logs are added to the AtomicRunner-logs folder in the home directory of the current user. Set the verbose and debug variables to $true in your privateConfi.ps1 file for maximum logging.

Refresh the Schedule

As new atomics are added, removed, or edited in the Atomic Red team library, you may want to refresh your schedule. Refreshing the schedule will update the Atomic test name, technique and supported platforms for each test on the schedule, remove entries for atomic tests that have been removed, and add any new tests that aren't already on your schedule. Any new tests added to the schedule will be disabled by default, change the enabled value to True if you want it to be active.

# This will refresh the CSV schedule found in the user's home directory at AtomicRunner\AtomicRunnerSchedule.csv
Invoke-RefreshExistingSchedule

Stop the Runner

A simple way to stop the atomic runner from it's continuous execution of atomics and rebooting you can simply add txt file called "stop" in the AtomicRunner folder. You can find the AtomicRunner folder in the basePath defined above, which is the current user's profile by default.

Atomic Runner Hooks

Users can define 4 different functions that will be called (if they exist) before/after atomic execution or before/after atomic test cleanup commands (only applies when calling Invoke-AtomicRunner):

  1. Invoke-AtomicRunnerPreAtomicHook
  2. Invoke-AtomicRunnerPostAtomicHook
  3. Invoke-AtomicRunnerPreAtomicCleanupHook
  4. Invoke-AtomicRunnerPostAtomicCleanupHook

See here for an example PowerShell module where you can provide the code to run for each of these hooks.