Vulnerability Analysis

MalwLess – Test Blue Team Detections Without Running Any Attack

October 30, 2018
3 Min Read
MalwLess - Test Blue Team Detections Without Running Any Attack
MalwLess is an open source tool that allows you to simulate system compromise or attack behaviours without running processes or PoCs. The tool is designed to test Blue Team detections and SIEM correlation rules. It provides a framework based on rules that anyone can write, so when a new technique or attack comes out you can write your own rules and share it a with the community.
These rules can simulate Sysmon or PowerShell events. MalwLess can parse the rules and write them directly to the Windows EventLog, then you can foward it to your event collector.
Usage
MalwLess Simulation Tool v1.1
Author: @n0dec
Site: https://github.com/n0dec/MalwLess

[Rule test file]: rule_test.json
[Rule test name]: MalwLess default
[Rule test version]: 0.3
[Rule test author]: n0dec
[Rule test description]: MalwLess default test pack.

[>] Detected rule: rules.vssadmin_delete_shadows
... Source: Sysmon
... Category: Process Create
... Description: Deleted shadows copies via vssadmin.
[>] Detected rule: rules.certutil_network_activity
... Source: Sysmon
... Category: Network connection detected
... Description: Network activity from certutil tool.
[>] Detected rule: rules.powershell_scriptblock
... Source: PowerShell
... Category: 4104
... Description: Powershell 4104 event for Invoke-Mimikatz.

Releases
You can download the latest release on https://github.com/n0dec/MalwLess/releases

Requirements
It is necessary to have sysmon installed in your system. https://docs.microsoft.com/en-us/sysinternals/downloads/sysmon

Commands
When you have downloaded the latest release version you can run it directly from an elevated command prompt.
To test the default rule set which is on rule_test.json just download it and run:

> malwless.exe

If you want to test a different rule set file, use the -r parameter:

> malwless.exe -r your_pack.json

To write a custom rule set check the writing sets section.

Creating rules
Anyone can create a rule. These are written in json with an easy format.

key values
enabled If the value is set to true the event will be written. If it’s set to false just ignore the rule.
source The source of the events. (Working on more supported sources…)
Sysmon
PowerShell
category For each source there are a list of different categories that can be specified.
description A simple rule description.
payload These are the values that will be added to the event. If you don’t indicate a specific payload the event will contain the values of the default configuration files located on conf.

Rule example

> malwless.exe

Sets

Contact
For any issue or suggestions contact on twitter @n0dec.

 

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