Introducing esfriend. A coordinated set of python wrappers for powerful applications on macOS, coming together to form a malware analysis sandbox. These application wrappers cooperate with each other using MongoDB to pass control to the next step.

I didn't realize the snapshot restoration feature through the macOS repair menu could serve as a free (but slower) replacement for Deep Freeze, so technically this whole sandbox is free (minus hardware cost)!

I've added the option to use eslogger output instead of ESF Playground on macOS Ventura (where eslogger is available). I'm still working on parsing the output and gathering additional data. This at least gives me the ability to investigate the more complex output of eslogger in comparison to ESF Playground.

esfriend no longer uses ESF Playground to record events, this means that macOS Ventura is required because we're using eslogger exclusively

I had to split "close" events and "exec" events into their own eslogger wrapper scripts. Allowing a single eslogger process to monitor for a single event type ensures that we collect as many events as accurately as possible.

I have also modified the css for the results website, as well as added more navigation options to help quickly analyze the output from eslogger and system log.

pictures coming soon

I've also been using Faronics Deep Freeze with SIP disabled and it seems to be working fine. This configuration allows easier execution of most malware that is packaged correctly.

ESF Playground - https://themittenmac.com/the-esf-playground/ - leaving this here because it helped get the ball rolling a lot

mitmproxy - https://mitmproxy.org/

ssdeep - https://ssdeep-project.github.io/ssdeep/index.html

p7zip - https://p7zip.sourceforge.net/

eslogger - Announced in this video https://developer.apple.com/videos/play/wwdc2022/110345/

Faronics Deep Freeze (69.30 USD) - https://www.faronics.com/products/deep-freeze/mac

esfriend is designed to use a physical macOS machine as the sandbox environment, then perform cleanup by using Faronics Deep Freeze.

This setup assumes you will use a Mac for the analysis machine. Windows and Linux should just work fine, configuration instructions are not yet included.

We all know the command:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

I'm using python3.9.13

Link to installer page: https://www.python.org/downloads/release/python-3913/

brew install mongodb-community mitmproxy ssdeep

Follow the instructions from brew to configure mongodb to automatically start on reboot

Important Note: The analysis process for esfriend uses a mitmproxy script to extract headers. Installing the python package for mitmproxy so that you can write additional scripts will replace the up to date mitmproxy on $PATH with an older version that will crash if used to capture packets from the sandbox machine.

Installing these to the system because I have not investigated environment variables with subprocess.

sudo -H python3.9 -m pip install pymongo ssdeep Flask Flask-Table

Important Note: You can install Flask and Flask-Table to a virtualenv to keep those modules off of the system python3.9 environment. The modules pymongo and ssdeep are used in subprocesses and necessary on the system at this time. Additionally, ssdeep is only used for greating goodlist entries, not comparing at this time.

Analysis machine can be any physical macOS machine, Intel or Apple silcon.

You'll need any x86 application to show the prompt to install Rosetta. Even running a simple hello world program will start the process.

Let me know if you need help generating an x86 MachO.

Again:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

brew install p7zip

Again - link to installer page: https://www.python.org/downloads/release/python-3913/

sudo -H python3.9 -m pip install pymongo

THe only module needed on the analysis machine at this time is pymongo.

esfriend/config.py and agent/agent_config.py need to be modified so they contain the correct path for corresponding applications, correct database connection string, and machine configuration.

Modify the shebangs in each file so they point to your python3.9 system installation for both Analysis (esfriend directory) and Sandbox (agent directory) scripts.

Ensure execution flags are set for scripts that are called through subprocess or cron.

sudo nano /etc/sudoers

Add the following line to the bottom of the file, replacing username with your own user account

username ALL=NOPASSWD:/sbin/reboot, /usr/bin/eslogger, /Users/username/Desktop/agent/agent.py

Make sure to replace the path to agent.py with the path on your system

Deep Freeze is not required to have a functional sandbox. You can create a snapshot using tmutil snapshot then restore the clean state using the macOS Repair menu. Deep Freeze does expedite the cleanup process by a considerable amount of time.

https://www.faronics.com/products/deep-freeze/mac

30 day trial is available

Switch the system to a frozen state

Important Note: Invalid key from payment processor. After purchasing the software you may need to contact support immediately because the license provided from the payment processer is not valid. Contacting support through the payment processor has been successful for me in the past.

Configure the included example launch daemon plist to point to all appropriate paths, also rename it to what every you would like.

Copy the file to the LaunchDaemons directory.

sudo cp com.mcarmanize.esfriend_agent.plist /Library/LaunchDaemons

Load the daemon.

sudo launchctl load -w /Library/LaunchDaemons/com.mcarmanize.esfriend_agent.plist

To unload the daemon.

sudo launchctl unload /Library/LaunchDaemons/com.mcarmanize.esfriend_agent.plist

After the agent is configured and running you can start the Analysis machine process

./esfriend.py

To clean the database (including the goodlist) and start over use

./esfriend.py --cleangoods

To clean only the job, machine, and run databases use:

./esfriend.py --clean

./submit.py sample_path timeout tags

Example:

./submit.py ~/SamplePath.o 60 cve-2022-0000,macho

You must include a timeout (in seconds) and tags (delimited however you like), there are no default values.

Results can be viewed using the esfriend web.py script

From the esfriend folder type:

export FLASK_APP=web

flask run

By default you should be able to navigate to: https://localhost:5000

goodlist.py can be used to generate a list of good event strings that should be ignored from a previous run. Upon execution it will prompt you with a list of runs and ask you to select which to generate good event strings from.