Part 2 -(WMI) :Detecting WMI-Based Attacks

In this blog post, we will delve into the significance of detecting WMI-based attacks and explore techniques to defend against them.

Command Line Auditing: A Game-Changer

The absence of command line auditing in an enterprise is akin to being blind to the majority of WMI-based attacks. In the absence of this critical tool, identifying malicious activities becomes an arduous task, requiring exhaustive efforts in traditional forensics. Fortunately, modern solutions like Microsoft Sysinternals' Sysmon and advanced endpoint detection and response tools offer the ability to record command lines, ensuring comprehensive coverage against stealthy WMI attacks.

Microsoft Sysmon: A Shield Against WMI Threats

Sysmon, a free Sysinternals tool, emerges as a formidable ally in the battle against WMI threats. Tailored for detecting malicious activities, Sysmon provides detailed logs without overwhelming collection capabilities. Its integration with command line auditing equips organizations with the visibility needed to identify and neutralize potential threats promptly.

Link: https://learn.microsoft.com/en-us/sysinternals/downloads/sysmon

Unveiling WMI Event Consumers:

Understanding the anatomy of WMI event consumers is paramount for effective defense. PowerShell commands to collect information about WMI event filters, consumers, and bindings are showcased, providing a blueprint for organizations to proactively identify and thwart potential threats. Best practices, such as querying both standard and non-standard namespaces, are explored to stay one step ahead of evolving attack techniques.

PowerShell Commands for WMI Event Consumer Collection:

Get-WMIObject -Namespace root\Subscription -Class __EventFilter
Get-WMIObject -Namespace root\Subscription -Class __EventConsumer
Get-WMIObject -Namespace root\Subscription -Class __FilterToConsumerBinding
Get-WMIObject -Namespace root\Default -Class __EventFilter
Get-WMIObject -Namespace root\Default -Class __EventConsumer
Get-WMIObject -Namespace root\Default -Class __FilterToConsumerBinding

Scaling Defense with PowerShell Remoting:

While auditing WMI event consumers on a single system is crucial, the real challenge lies in scaling defense across multiple systems. PowerShell remoting allows organizations to collect comprehensive data, which can be analyzed through databases like ELK stack or Splunk.

PowerShell Command for Remote WMI Event Consumer Collection:

# Read computer names from a text file
$ComputerNamesFile = "C:\Path\To\Your\ComputerNames.txt"
$RemoteComputers = Get-Content $ComputerNamesFile
$Credentials = Get-Credential

$ScriptBlock = {
    Get-WMIObject -Namespace root\Subscription -Class __EventFilter
    Get-WMIObject -Namespace root\Subscription -Class __EventConsumer
    Get-WMIObject -Namespace root\Subscription -Class __FilterToConsumerBinding
}

# Invoke the script block on remote computers
Invoke-Command -ComputerName $RemoteComputers -ScriptBlock $ScriptBlock -Credential $Credentials

Ensure that your text file (ComputerNames.txt) contains one computer name per line. Modify the path in $ComputerNamesFile to point to the actual location of your text file.

Conclusion:

Implementing robust command line auditing, leveraging tools like Sysmon, and embracing PowerShell for detection are critical steps in fortifying defenses against stealthy WMI threats. By understanding the dual nature of WMI and PowerShell, organizations can turn these tools into powerful allies in the ongoing battle for cybersecurity. Stay vigilant, stay secure!

Akash Patel