Automating the detection of Mimikatz with ELK

I’ve been going through CyberWarDog’s Threat Hunting posts as of late and stumbled upon his ‘Hunting for In-Memory Mimikatz’ Series. The methods used to build signatures are very straight forward and seem to remove a barrier to entry for figuring out how to profile malicious tools.

The method used to detect Mimikatz is referred to as grouping which consists of taking a group of unique artifacts and identifying when multiple of the unique artifacts appear together. So for this post, we will use Cyberwardog’s guidance to build an alert for the detection of Mimikatz using Sysmon and the ELK Stack.

This post assumes you already have an ELK Stack stood up with ElastAlert configured. This can be stood up in minutes with the HELK. (ElastAlert will be merged soon)

I want to start out by saying this is definitely not the most elegant solution. The idea was simple enough, alert when 5 DLL’s are accessed within 1 second of each other from the same host. Unfortunately, ElastAlert does not have this functionality built in, so Python it is..

The Sysmon config I am using is the Ion-Storm sysmon config. By default, the proper events are forwarded. Lines 571-579.

To get started, we need a script to handle some of the logic required to verify a couple things before we fire off an alert. I tried to make the python tool as modular as possible so that we can easily alert on other event ‘groupings’.

The 5 DLL’s we will be detecting are:






We will also only be detecting these if they happen to be accessed within one second of each other.

On your server running your ELK stack:

sudo nano /bin/

Paste in:

sudo chmod 755 /bin/

This script handles all of our logic and also sends our Slack Notification. Using the options, we can alert on any combination of events.

Add our individual rules to our alerts rules directory.

Grab our rules off GitHub:

git clone

Copy our rules into our ElastAlert rules directory:

sudo cp ElastAlertGrouper/alert_rules/* /etc/elastalert/alert_rules/

We now have 6 new rules in our rule directory. Each rule with a DLL name alerts when that given DLL is loaded.

As you can see, we have the typical alert rule options and we are querying for samlib in event_data.ImageLoaded. When this alert is tripped, it calls our python script with this command:

python3 /bin/ –T D –a Mimikatz –o /tmp/mimikatz –c $ComputerName
-T is telling the script what action to take, in this case, we are just writing the hostname to a file so we want to use the ‘Document’ or D option.

-a is the alert type, in this case Mimikatz

–c is the hostname taken from the alert.

This is reflected across all DLL alerts. So when mimikatz is ran, the output file will have 5 hostnames written there.

Now let’s take a look at our Mimikatz rule.

This alert uses frequency as well as a different index. ElastAlert actually has its own index that indexes everytime an alert is queried. So now we can check this index if all five of the DLL alerts were fired in less than one second. It does this by filtering for only the DLL rules, only returning those with the alert_sent flag set to true, and alerting only if identifies 5 results within 1 second.

You will need to generate a Slack Web Hook and replace ‘SLACKWEBHOOK’ with your web hook. 

The alert is a command calling our Python script again:

python3 /bin/ –T S –S SLACKWEBHOOK –a Mimikatz –t 5
-T is telling the script that we want to perform a ‘Send’ action.

-S needs to have our Slack Web Hook

-a tells the script what detection type we are alerting on

-t tells the script to only alert if there are 5 or more unique hostnames in our output file.

This last part is important. This number should always be the amount of rules that make up your grouping.

Run Mimikatz:


One thing to keep in mind is that these have been tested in a lab environment with a small population of end points. Deploying this in production will likely involve major tuning.

Check out these labs: for an in-depth guide on how to set this stuff up manually as well as build the lab around it.

If you run into any issues, feel free to reach out to me on Twitter or by email!

The advice and scripts contained and referenced in this point are provided with no warranty. As always, never blindly trust scripts off the internet.


Using ElastAlert to Help Automate Threat Hunting

I first want to say thanks to CyberWarDog for his fantastic lab walk through for setting up a Threat Hunting Lab. It is hands down the best guide I have read to getting started with Threat Hunting. I followed his guide and got my lab completely setup. I then decided that Elastalert would be pretty nice for getting some of the highly likely IOC’s sent off to a security team for further analysis. This post will guide you through setting up Elastalert to get notifications when certain actions are logged.

This guide assumes you have gone through all parts of CyberWarDogs tutorials:

Not required, but it also assumes that you have set up Enhanced Powershell Logging so that we can begin to capture useful PowerShell data.

Also not required but useful for this guide: A Slack Channel.

Cool, ready to go?

  • SSH or Console into your Ubuntu server running your ELK stack.
  • Download Elastalert from Yelp’s GitHub.
git clone
  • Copy Elastalert to ‘/etc/’
sudo cp -r elastalert /etc/
  • Change directory into your new Elastalert directory.
cd /etc/elastalert
  • If not already installed, install pip.
sudo apt install python-pip
  • Install Elastalert
pip install elastalert
  • Install ElasticSearch-py
  • pip install "elasticsearch>=5.0.0"
  • Install dependencies:
pip install -r requirements.txt
  • Lets make a directory for our Elastalert templates:
sudo mkdir templates
  • Change directory into our new templates directory
cd templates
  • Create a new template for monitoring commands executed:
sudo nano cmd_template.yaml


es_host: localhost
es_port: 9200
index: winlogbeat-*
- terms:
    event_data.CommandLine: ["PLACEHOLDER"]
type: any
- slack
slack_webhook_url: "SLACK_WEB_HOOK"

es_host: This is the host your ELK stack is running on.

es_port: This is the port Elastic Search is listening on.

index: This is the index you setup with CyberWarDog’s blog.

filter: This is tell Elastalert to filter its search, in this case, we are filtering with ‘terms’ and we are looking for ‘event_data.CommandLine’ that equals whatever we put in place for PLACEHOLDER.

type: This means that Elastalert should alert on an matches that our Filter hits. We could also specify this Type to alert on new values identified, a spike in certain logs, a lack of logs and a bunch of other cool things.

alert: This tells elastalert how to alert you! There are a bunch of ways to get these alerts and I chose Slack for its simplicity to set up and use. For more options you can visit:

  • Create a new template for monitoring powershell commands executed:
sudo nano powershell_template.yaml


es_host: localhost
es_port: 9200
index: winlogbeat-*
- terms:
    powershell.scriptblock.text: ["PLACEHOLDER"]
type: any
- slack
slack_webhook_url: "SLACK_WEB_HOOK"
  • Create your main config.yaml file.
cd ..
sudo nano config.yaml


rules_folder: alert_rules
    seconds: 30
    seconds: 60
es_host: localhost
es_port: 9200
    days: 1
writeback_index: elastalert_status
alert_text: "Username: {0} \nHost: {1} \nTime: {2} \nLog:{3}"
alert_text_type: alert_text_only
alert_text_args: ["","host", "@timestamp","log_name"]

To change the body of the alert, you can modify the last three lines, you can add or remove attributes to include in your report.

  • Create our Rules directory:
sudo mkdir alert_rules
cd alert_rules
  • Copy our templates here:
sudo cp ../templates/* .
  • Make copies of our templates.
cp cmd_template.yaml cmd_whoami.yaml
cp powershell_template.yaml powershell_invoke_webrequest.yaml
  • Modify cmd_whoami.yaml to alert when whoami is executed.
sudo nano cmd_whoami.yaml
  • Replace the PLACEHOLDER text in both locations with ‘whoami’, you can also copy this file many times over to alert on multiple commands ran.
es_host: localhost
es_port: 9200
name: "whoami"
index: winlogbeat-*
- terms:
 event_data.CommandLine: ["whoami"]
type: any
- slack
slack_webhook_url: "SLACK_WEB_HOOK"
sudo nano powershell_invoke_webrequest.yaml
es_host: localhost
es_port: 9200
name: "invoke-webrequest"
index: winlogbeat-*
- terms:
    powershell.scriptblock.text: ["webrequest"]
type: any
- slack
slack_webhook_url: "SLACK_WEB_HOOK"

Only query lowercase terms.

  • Remove the two template files we copied over:
sudo rm *template.yaml
  • Run elastalert-create-index and follow the prompts

Remember: You host is localhost and your port is 9200, if you followed CyberWarDog’s guide, you also do not have authentication set up for ElasticSearch (You used nginx instead) so leave username and password empty. You also don’t have SSL or TLS setup.

  • Change directory back to /etc/elastalert
cd /etc/elastalert
  • Run elastalert –verbose
elastalert --verbose
  • Go to your Windows machine running winlogbeat and open up your command prompt.
  • Enter whoami and monitor your slack.
  • Profit

Commands you may want to monitor for:




Powershell Functions you may want to monitor on:





If you are going to take this Threat Hunting thing seriously, you will most likely want to add alerts for Spikes, Frequency, Cardinality and a billion other types of things that are good ideas to check for with any Production system.

For comments, questions, concerns you can reach me at Twitter or via Email

[UPDATE: Several issues fixed 12/26]