# Docker Forensics
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## Container modification
There are suspicions that some docker container was compromised:
```bash
docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cc03e43a052a lamp-wordpress "./run.sh" 2 minutes ago Up 2 minutes 80/tcp wordpress
```
You can easily **find the modifications done to this container with regards to the image** with:
```bash
docker diff wordpress
C /var
C /var/lib
C /var/lib/mysql
A /var/lib/mysql/ib_logfile0
A /var/lib/mysql/ib_logfile1
A /var/lib/mysql/ibdata1
A /var/lib/mysql/mysql
A /var/lib/mysql/mysql/time_zone_leap_second.MYI
A /var/lib/mysql/mysql/general_log.CSV
...
```
In the previous command **C** means **Changed** and **A,** **Added**.\
If you find that some interesting file like `/etc/shadow` was modified you can download it from the container to check for malicious activity with:
```bash
docker cp wordpress:/etc/shadow.
```
You can also **compare it with the original one** running a new container and extracting the file from it:
```bash
docker run -d lamp-wordpress
docker cp b5d53e8b468e:/etc/shadow original_shadow #Get the file from the newly created container
diff original_shadow shadow
```
If you find that **some suspicious file was added** you can access the container and check it:
```bash
docker exec -it wordpress bash
```
## Images modifications
When you are given an exported docker image (probably in `.tar` format) you can use [**container-diff**](https://github.com/GoogleContainerTools/container-diff/releases) to **extract a summary of the modifications**:
```bash
docker save > image.tar #Export the image to a .tar file
container-diff analyze -t sizelayer image.tar
container-diff analyze -t history image.tar
container-diff analyze -t metadata image.tar
```
Then, you can **decompress** the image and **access the blobs** to search for suspicious files you may have found in the changes history:
```bash
tar -xf image.tar
```
### Basic Analysis
You can get **basic information** from the image running:
```bash
docker inspect
```
You can also get a summary **history of changes** with:
```bash
docker history --no-trunc
```
You can also generate a **dockerfile from an image** with:
```bash
alias dfimage="docker run -v /var/run/docker.sock:/var/run/docker.sock --rm alpine/dfimage"
dfimage -sV=1.36 madhuakula/k8s-goat-hidden-in-layers>
```
### Dive
In order to find added/modified files in docker images you can also use the [**dive**](https://github.com/wagoodman/dive) (download it from [**releases**](https://github.com/wagoodman/dive/releases/tag/v0.10.0)) utility:
```bash
#First you need to load the image in your docker repo
sudo docker load < image.tar 1 ⨯
Loaded image: flask:latest
#And then open it with dive:
sudo dive flask:latest
```
This allows you to **navigate through the different blobs of docker images** and check which files were modified/added. **Red** means added and **yellow** means modified. Use **tab** to move to the other view and **space** to collapse/open folders.
With die you won't be able to access the content of the different stages of the image. To do so you will need to **decompress each layer and access it**.\
You can decompress all the layers from an image from the directory where the image was decompressed executing:
```bash
tar -xf image.tar
for d in `find * -maxdepth 0 -type d`; do cd $d; tar -xf ./layer.tar; cd ..; done
```
## Credentials from memory
Note that when you run a docker container inside a host **you can see the processes running on the container from the host** just running `ps -ef`
Therefore (as root) you can **dump the memory of the processes** from the host and search for **credentials** just [**like in the following example**](../../linux-hardening/privilege-escalation/#process-memory).
{% hint style="success" %}
Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\
Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
Support HackTricks
* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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