APT Simulator

Important: Don't just ZIP download or clone the repo if you don't plan to develop some test. Use the package in the release which contains a packaged version with encrypted archives that don't contain cleartext samples and tools.

APT Simulator is a Windows Batch script that uses a set of tools and output files to make a system look as if it was compromised. In contrast to other adversary simulation tools, APT Simulator is designed to make the application as simple as possible. You don't need to run a web server, database or any agents on set of virtual machines. Just download the prepared archive, extract and run the contained Batch file as Administrator. Running APT Simulator takes less than a minute of your time.

Use Cases

1. POCs: Endpoint detection agents / compromise assessment tools
2. Test your security monitoring's detection capabilities
3. Test your SOCs response on a threat that isn't EICAR or a port scan
4. Prepare an environment for digital forensics classes

Motives

Customers tested our scanners in a POC and sent us a complaint that our scanners didn't report on programs that they had installed on their test systems. They had installed an Nmap, dropped a PsExec.exe in the Downloads folder and placed on EICAR test virus on the user's Desktop. That was the moment when I decided to build a tool that simulates a real threat in a more appropriate way.

Why Batch?

• Because it's simple: Everyone can read, modify or extend it
• It runs on every Windows system without any prerequisites
• It is closest to a real attacker working on the command line

Focus

The focus of this tool is to simulate adversary activity, not malware. See the Advanced Solutions section for advanced tools to simulate adversary and malware activity.

Getting Started

1. Download the latest release from the "release" section
2. Extract the package on a demo system (Password: apt)
3. Start a cmd.exe as Administrator
4. Navigate to the extracted program folder and run APTSimulator.bat

Avoiding Early Detection

The batch script extracts the tools and shells from an encrypted 7z archive at runtime. Do not download the master repo using the "download as ZIP" button. Instead use the official release from the release section.

AV Excluder

APT Simulator contains a module named "AVExcluder" that tries to register the used %APTDIR% as AV exclusion in typical AV solutions. As I do not have access to all of the AV software products in the market, please report errors or add new exclusions as pull requests.

Extending the Test Cases

Since version 0.4 it is pretty easy to extend the test sets by adding a single .bat file to one of the test-set category folders.

E.g. If you want to write a simple test case for "privilege escalation", that uses a tool named "privesc.exe", clone the repo and do the following:

1. Add your tool to the toolset folder
2. Write a new batch script privesc-1.bat and add it to the ./test-sets/privilege-escalation folder
3. Run build_pack.bat
4. Add your test case to the table and test sets section in the README.md
5. Create a pull request

Tool and File Extraction

If your script includes a tool, web shell, auxiliary or output file, place them in the folders ./toolset or ./workfiles. Running the build script build_pack.bat will include them in the encrypted archives enc-toolset.7z and enc-files.7z.

Extract a Tool

"%ZIP%" e -p%PASS% %TOOLARCH% -aoa -o%APTDIR% toolset\tool.exe > NUL

Extract a File

"%ZIP%" e -p%PASS% %FILEARCH% -aoa -o%APTDIR% workfile\tool-output.txt > NUL

Detection

The following table shows the different test cases and the expected detection results.

• AV = Antivirus
• NIDS = Network Intrusion Detection System
• EDR = Endpoint Detection and Response
• SM = Security Monitoring
• CA = Compromise Assessment

Test Case	AV	NIDS	EDR	SM	CA
Collect Local Files					X
C2 Connects	(X)	X	X	X
DNS Cache 1 (Cache Injection)	(X)	X		X	X
Malicious User Agents (Malware, RATs)		X	X	X
Ncat Back Connect (Drop & Exec)	X		X	X	X
WMI Backdoor C2			X	X	X
LSASS Dump (with Procdump)			X	X	X
Mimikatz 1 (Drop & Exec)	X		X	X	X
WCE 1 (Eventlog entries)			X	X	X
Active Guest Account Admin			X	X	X
Fake System File (Drop & Exec)			X	X	X
Hosts File (AV/Win Update blocks)	(X)		X		X
Obfuscated JS Dropper	(X)	X	X	X	X
Obfuscation (RAR with JPG ext)					(X)
Nbtscan Discovery (Scan & Output)		X	X	(X)	X
Recon Activity (Typical Commands)			X	X	X
PsExec (Drop & Exec)			X	X	X
Remote Execution Tool (Drop)	(X)				X
At Job			X	X	X
RUN Key Entry Creation			X	X	X
Scheduled Task Creation			X	X	X
StickyKey Backdoor			X		X
UserInitMprLogonScript Persistence			(X)	X	X
Web Shells	X		(X)		X
WMI Backdoor			X		X

Cobalt Strike Beacon Activity

You should now be able to find events in your security monitoring solution (SIEM, EDR etc.) for the following keywords:

Named Pipes

• MSSE-1337-server
• msagent_fedac123
• postex_ssh_fedac123
• 334485 (used in Get System activity)

Note: No Named Pipe Monitoring? You can use Sysmon + this config and this Sigma rule to get you started.

Get System Activity

• b6a1458f396 (multiple events: new service registration and process creation)

Note: No events? you can use this Sigma rule to get you started.

C2 Beaconing

• http://10.0.2.15/pixel.gif
• https://operaa.net:443/jquery-3.2.2.min.js
• https://23.108.57.148:443/jquery-3.2.2.full.js

Test Sets

Collection

Collect Local Files

• drops pwdump output to the working dir
• drops directory listing to the working dir

Command and Control

C2 Connects

• Uses Curl to access well-known C2 servers

DNS Cache 1

• Looks up several well-known C2 addresses to cause DNS requests and get the addresses into the local DNS cache

Malicious User Agents

• Uses malicious user agents to access web sites

Ncat Back Connect

• Drops a PowerShell Ncat alternative to the working directory and runs it to back connect to a well-known attacker domain