Oct 30, 2020
1 min read
How to use Gremlin to blackhole an external address from a container
In this tutorial, we’ll be using Gremlin to run a blackhole attack that blocks an external address. In this example, we’ll block access to example.com.
First, we’ll launch our container, a simple ubuntu container:
sudo docker run -l service=curl --name curl -d nginxObtain the container id, in this example it is 30d570653c9f
docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
30d570653c9f nginx “/docker-entrypoint.…” 22 seconds ago Up 21 seconds 80/tcp curlNow we’ll hop in the container to run curl and confirm the blackhole is working as expected:
docker exec -it 30d570653c9f /bin/bashCurl to get example.com
curl example.comThe result from curling example.com
<!doctype html>
<html>
<head>
<title>Example Domain</title>....
Now we’ll block the ability to reach example.com.
In this example I am spinning up a gremlin agent to run an attack on the container we created, it is then blocking the ability for that container to reach example.com for 3000 seconds:
sudo docker run -it --cap-add=NET_ADMIN -e GREMLIN_TEAM_ID="${GREMLIN_TEAM_ID}" -e GREMLIN_TEAM_SECRET="${GREMLIN_TEAM_SECRET}" -v /var/run/docker.sock:/var/run/docker.sock gremlin/gremlin attack-container 30d570653c9f blackhole -l 3000 -h example.com
