PowerShell allows system administrators to execute numerous tasks quickly and precisely. It combines a task-based command-line shell, scripting language, and configuration management framework into one convenient solution.
Microsoft provides comprehensive documentation of PowerShell that is freely accessible and free for students and professionals alike. Furthermore, various self-study and guided courses cover specific uses for this tool as a learning resource and professional aid.
Scripting
PowerShell scripts enable system administrators to perform complex and repetitive tasks that a GUI cannot, as well as simultaneously perform operations on multiple systems using its remote access functionality. Furthermore, PowerShell provides system administrators with tools like variables, cmdlets, modules and providers that assist them with accomplishing their work efficiently.
PowerShell scripts are saved in.ps1 files that can be executed either from within PowerShell itself or the Windows Scheduler. PowerShell has built-in features to manage Windows Scheduled Tasks; whether you need to change their start time, location or cancel them altogether, PowerShell provides all of the tools to accomplish these goals.
PowerShell differs significantly from command line systems by being entirely object-oriented. Every real world object has attributes (properties) which describe it, as well as methods which take action with it to perform specific tasks – for instance a cat may have characteristics like color, size and age; its methods could include jumping, blinking and purring as actions it can take in its daily routines.
Each PowerShell cmdlet (command) is a function with its own parameters and return values, just like any programming language function would. These arguments and values include integer and string variables as well as calling other functions with their parameters as arguments to this function.
PowerShell’s advanced object-oriented features also allow the storage of objects as self-contained units known as modules, making them invaluable to administrators and script developers for creating reusable code units for use in scripts. Furthermore, these modules also create an isolated runspace environment within PowerShell itself.
PowerShell modules may be referenced either using their full name or shorthand, which corresponds to their command name. For instance, to display the contents of a specific file use “get-file file path>.” Press TAB for autocompletion or type manually the path name into PowerShell window – alternatively you may drag and drop files directly from Windows Explorer or Desktop into it!
Automation
PowerShell is an invaluable tool for IT pros, sysadmins and developers looking to automate processes. With its foundational commands, community modules and scripting capabilities – not to mention its ease of use – PowerShell should be in any administrator’s tool belt. Unfortunately though, due to all its options and features it’s easy to get lost among all its cmdlets, flags, filters and ways of telling PowerShell what action should take place.
Microsoft has designed the PowerShell Object Model as an aid in meeting this challenge by providing structure and underlying functionality that you can use to access system objects. The PowerShell Object Model consists of classes and interfaces you can use when developing PowerShell scripts; these classes and interfaces can be divided into various categories like objects, variables, functions and cmdlets for convenient script building and execution.
PowerShell can be used as a command-line shell to manage and control Windows Management Instrumentation (WMI) and Component Object Model (COM). For instance, creating a PowerShell script that retrieves information about an existing process before sending it across network connections to another program. You could even use PowerShell remoting capabilities to manage a remote computer remotely.
PowerShell scripts can run on all versions of Windows as long as the necessary libraries are installed, making them ideal for both writing and using on Mac OS X computers. Furthermore, thanks to its convenient Object Model capabilities, data can easily pass between platforms and programs using PowerShell scripts.
Not only can you use PowerShell scripts and tools like Command Prompt in Windows to write and run scripts, but you can also utilize other parts of Windows operating system tools for specific actions that PowerShell alone cannot. For instance, Command Prompt allows you to rename files by replacing their names with an asterisk: for instance “rename C:Scripts*.txt”.
To monitor Windows systems with SL1, it is essential that the necessary credentials exist on each device as well as an action policy to correspond with an event. For more information, refer to Configuring Windows Systems for Monitoring with SL1.
Create an action policy using a PowerShell script to execute custom actions in response to events that happen on a device. For more information, see Creating Windows PowerShell Automation Action.
Remoting
PowerShell provides multiple methods for remotely controlling another computer. You can use the Enter-PSSession cmdlet to connect, or Invoke-Command can be used from a local system to send commands directly to remote systems – useful for copying files between computers or transferring data across systems. Invoke-Command also lets you run scripts remotely – an ideal way to automate routine tasks.
Step one in remote control is activating Windows PowerShell remoting on the target machine. To do this, launch Windows PowerShell in administrative mode and run this cmdlet:
This cmdlet configures the startup type for the WinRM service, enables firewall exceptions and creates the WinRM listener. Each action will require you to confirm; if you wish to bypass them altogether you can run this cmdlet with its Force parameter instead.
Network administrators can find PowerShell remoting an invaluable asset. It enables you to run commands simultaneously on multiple machines, and even help work around software or program limitations. For instance, if your company’s security policy mandates two-factor authentication or changing passwords every two months for all employees, creating a PowerShell script that enforces that protocol across the board will make your job much simpler.
PowerShell remoting works best within an Active Directory environment, though it can also be utilized on standalone or workgroup computers. Furthermore, using the open-source release of PowerShell you can also remote into servers running Linux or macOS operating systems for easier cross-platform system management and scaling of IT operations.
PowerShell remoting provides another advantage by helping troubleshoot issues on remote machines. If you aren’t sure which command caused an error message, use Get-Help cmdlet to see all installed commands installed locally or remotely and get-Command with parameters to narrow your search further. Be sure to add plenty of comments when writing scripts that will be reused so others will have an understanding of its purpose and meaning.
Security
PowerShell can bring many advantages to security teams, yet it should not be taken for granted. As an essential tool for performing administrative functions, PowerShell provides cyber threat actors (CTAs) an avenue of bypassing security controls. PowerShell’s extensibility and user friendliness aid defenders but may allow malicious actors to utilize PowerShell for fileless malware attacks that avoid anti-virus detection.
CTAs make use of scripts to perform various actions, including scanning network drives and event logs for exploitable information, hiding commands locally or remotely and executing them so as to execute fileless attacks against their targets easily.
PowerShell can also be used to bypass program limitations, such as forcing users to enable two-factor authentication or change passwords at regular intervals. This makes it an excellent asset in threat hunting environments where data from specialized stores such as Windows registries or event logs need retrieving quickly and reliably.
CTAs may use PowerShell to gain privileged access to hosts and conduct more sophisticated cyberattacks, including using it to modify registry keys or inject malicious code, as well as run Remote Desktop Protocol man-in-the-middle attacks.
IT and security professionals rely on PowerShell for managing systems, but should limit its deployment only when absolutely necessary for doing their jobs. Standard users should not have access to this powerful command language as this poses a substantial risk to any organization.
Defense against PowerShell attacks requires an effective security architecture consisting of firewalls, IDS/IPS systems, antivirus software and the Microsoft Security Center. Furthermore, deploying and using security features such as AppLocker script enforcement, deep script block logging and over-the-shoulder transcription should also be utilized to provide maximum protection from such attacks.
Organizations looking to further harden and minimize their PowerShell attack surface should implement Just Enough Administration on high-value systems and implement Windows OS hardening techniques such as sandboxing with Deployment Server as part of their strategy for protecting against attacks such as pass-the-hash, Kerberos Golden Tickets, RDP man-in-the-middle attacks, Security Access Token abuse and Security Access Token abuse while mitigating against lateral movement attacks such as ransomware discussed in SEC504 and other SANS hacking courses.
