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TomWechsler
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Joined Mar 24, 2020
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Threat Hunting with PowerShell - Security even with a small budget - there is no excuse!
Dear Threat Hunter, Lack of IT security is often excused by little or no available money. In my view, this is a very poor excuse. In this article I will try to give you a jump start on how to investigate threats with PowerShell. Is this a comprehensive and conclusive list of how you can find or detect threats/threats? NO, absolutely not. But it is meant to provide you with the support that you need to move forward on your own. Let's talk about the "general conditions": 1. If you use the PowerShell scripts I show/explain in this article, this is entirely your responsibility. I use the scripts in different situations, they are not dangerous, but you should already know what you are doing. 2. Written permission! If you are not sure if you are allowed to do an investigation, organize a written permission from your supervisor. 3. In the different scripts I sometimes (for this article deliberately) use standard search words like "malware", "malicious", "hacker" etc. Such search patterns/search words need to be customized, of course. These simply serve as an example. 4. The last part of the article examines some Microsoft cloud services. I am absolutely aware that there are a huge number of tools for hunting in the Microsoft cloud services. It starts with Azure Sentinel and continues with Cloud App Security. Since the focus is on a small budget, I'll leave those tools on the side. Introduction: So first, why should you use PowerShell for threat hunting? PowerShell is a useful threat hunting tool because it is a powerful scripting language and a platform for automating tools and accessing data across any Windows environment. It allows you to quickly gather information from various sources such as event logs, registries, files, and processes. Additionally, it can also be easily integrated with other tools and technologies making it a flexible and efficient tool for threat hunting. Some common use cases for PowerShell in the threat hunting environment include automated collection of log data, identification of unusual behavior anomalies in the system, the discovery of malware or malicious activity by known signatures or patterns or behaviors. These are just a few examples of how PowerShell can be used in a threat hunting capacity. Its versatility and ability to access and manipulate data from across the Windows environment make it a very valuable tool for any security professional. Threat Hunting in PowerShell - Use Cases: All right. So now that we understand where PowerShell can benefit an organization from a threat hunting perspective. Let's take a deeper look at some of the actual use cases you might encounter on a day to day basis, first being identify malicious processor files. So specifically, you can conduct raw file analysis to sift through different data shares to look for particular files in question whether that be a signature or even an extension of a certain file being able to quickly search and triage through files is an extreme benefit of using PowerShell for threat hunting. But how exactly do we start, what can we use as a guide? For example, the MITRE ATT&CK Framework. Here are a few examples: Indicator Removal: Clear Windows Event Logs https://attack.mitre.org/techniques/T1070/001/ Event Triggered Execution: Installer Packages https://attack.mitre.org/techniques/T1546/016/ Hide Artifacts: NTFS File Attributes https://attack.mitre.org/techniques/T1564/004/ Command and Scripting Interpreter: PowerShell https://attack.mitre.org/techniques/T1059/001/ Command and Scripting Interpreter: Windows Command Shell https://attack.mitre.org/techniques/T1059/003/ Event Triggered Execution: Windows Management Instrumentation Event Subscription https://attack.mitre.org/techniques/T1546/003/ Credentials from Password Stores: Windows Credential Manager https://attack.mitre.org/techniques/T1555/004/ Abuse Elevation Control Mechanism: Bypass User Account Control https://attack.mitre.org/techniques/T1548/002/ The MITRE ATT@CK framework provides a comprehensive and regularly updated overview of tactics, techniques, and procedures (TTPs) used by various threat actors. We can locate these TTPs using PowerShell, here are a few examples: Indicator Removal: Clear Windows Event Logs https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Active_Directory/06_Account_Events.ps1 Event Triggered Execution: Installer Packages https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/08_Get-ItemProperty_Software.ps1 Hide Artifacts: NTFS File Attributes https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/08_Get-ItemProperty_Software.ps1 Windows Installer Service is running https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/01_WIS_is_running.ps1 Search Alternate Data Streams on NTFS File Systems https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/02_Search_ADS_on_NTFS%20_(specific%20file).ps1 https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/03_Search_ADS_on_NTFS_file_systems.ps1 Read the Contents of a File https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/06_Read_the_contents_file.ps1 Locating Data Patterns within a File https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/05_locating_data_patterns_within_file.ps1 Search for Encoding with Regex https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/07_Search_encoding_with_regex.ps1 Search for Command and Scripting Interpreter: https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Tactics_Techniques_Procedures_(TTPs)/04_Searching_for_PIDs.ps1 Threat hunting in different environments with PowerShell: Coming examples are about collecting information in very different environments. Also here a few examples as a kind => as first starting points: Hunt for Threats in Active Directory: https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Active_Directory/01_Resetting_Password_Unlocking_Accounts.ps1 https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Active_Directory/02_Search_stale_accounts.ps1 https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Active_Directory/03_Users_without_Manager.ps1 https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Active_Directory/04_Password_Expiration.ps1 https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Active_Directory/05_Group_Membership_Report.ps1 https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Active_Directory/06_Account_Events.ps1 https://github.com/tomwechsler/Active_Directory_Advanced_Threat_Hunting/blob/main/PowerShell/Tracking_the_Source_of_Account_Lock_Outs_and_Bad_Passwords.ps1 https://github.com/tomwechsler/Active_Directory_Advanced_Threat_Hunting/blob/main/PowerShell/Finding_Unused_Group_Policy_Objects.ps1 Some of the scripts are structured in such a way that they must be executed block by block/line by line. So do not execute the whole script at once. Pay attention to the different information that is collected. With some investigations in the Active Directory accounts can be indicated like "guest" or "krbtgt", there must be clear of course how this information is to be estimated. Depending on how and what information is searched. Hunt for Threats in Exchange Online: https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Exchange_Online/Exchange_Mailbox_LastLogin.ps1 Find mailboxes with the last login. Hunt for Threats in Azure: https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Azure/Collect_vms_subscription.ps1 We search Azure for all virtual machines in a subscription. https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_Azure/02_Graph_Create_Time_Last_Password.ps1 When was the last password change and when were the accounts created? Hunt for Threats in SharePoint: https://github.com/tomwechsler/Threat_Hunting_with_PowerShell/blob/main/Hunting_SharePoint_Online/SharePoint_Online_specific_files.ps1 With this script we search for files with the extension .ps1 in a SharePoint Online page. Summary: Is this the best tactic to hunt for threats? No! There are many different tactics/techniques to search for threats. First of all, there are a huge number of different tools that can be used, for example SIEM/SOAR (Security Information and Event Management/Security Orchestration, Automation and Response). These tools are really great, sometimes cost a lot and often it takes a lot of knowledge to use such tools. But what is the use of such tools if the information generated by these tools cannot be understood properly, not very much. For this reason, I have tried in this article with simple tools to generate information that hopefully can be interpreted. Is finished here at this point. NO, the journey continues. The examples in this article are neither exhaustive nor complete, but they should give you a starting point. I hope you can build on this foundation. I hope that this information is helpful to you and that you have received a good "little" foundation. But I still hope that this information is helpful for you. Thank you for taking the time to read the article. Happy Hunting, Tom Wechsler P.S. All scripts (#PowerShell, Azure CLI, #Terraform, #ARM) that I use can be found on github! https://github.com/tomwechslerActive Directory Advanced Threat Hunting - Tracing the cause of account lockouts and password errors
Dear Microsoft Active Directory friends, In this article we are going on a "search for clues" :-). In the life of an IT administrator, you have certainly often had to reset a user's password or remove an account lockout. Now the question arises on which system the account was locked or on which system the password was entered incorrectly. In order to determine this information with PowerShell, some preparations must be made. "Advanced Audit Policy Configuration" must be configured in the group policies. This article from Microsoft provides a good starting point: https://learn.microsoft.com/en-us/defender-for-identity/deploy/event-collection-overview In my example, I have adapted the Default Domain Controls Policy. Before we begin, here is some important information about MITRE techniques: Account Access Removal: https://attack.mitre.org/techniques/T1531/ User Account: https://attack.mitre.org/datasources/DS0002/ Brute Force: Password Spraying: https://attack.mitre.org/techniques/T1110/003/ Account lockouts are logged in the Windows event logs with the ID 4740. We will therefore focus on this event ID first. The start of the PowerShell script looks like this: #Prep work for lockouts, Account lockout Event ID $LockOutID = 4740 #Find the PDC (Get-ADDomain).PDCEmulator $PDCEmulator = (Get-ADDomain).PDCEmulator #Connect to the PDC Enter-PSSession -ComputerName $PDCEmulator #Query event log Get-WinEvent -ComputerName $PDCEmulator -FilterHashtable @{ LogName = 'Security' ID = $LockOutID } #Parse the event and assign to a variable $events = Get-WinEvent -ComputerName $PDCEmulator -FilterHashtable @{ LogName = 'Security' ID = $LockOutID } #Examine some properties $events[0].Message #Regex? $events[0].Message -match 'Caller Computer Name:\s+(?<caller>[^\s]+)' $Matches.caller #Cool, but not as easy as: $events[0].Properties $events[0].Properties[1].Value #For all events: ForEach($event in $events){ [pscustomobject]@{ UserName = $event.Properties[0].Value CallerComputer = $event.Properties[1].Value TimeStamp = $event.TimeCreated } } #And we'll make that a function Function Get-ADUserLockouts { [CmdletBinding( DefaultParameterSetName = 'All' )] Param ( [Parameter( ValueFromPipeline = $true, ParameterSetName = 'ByUser' )] [Microsoft.ActiveDirectory.Management.ADUser]$Identity ) Begin{ $LockOutID = 4740 $PDCEmulator = (Get-ADDomain).PDCEmulator } Process { If($PSCmdlet.ParameterSetName -eq 'All'){ #Query event log $events = Get-WinEvent -ComputerName $PDCEmulator -FilterHashtable @{ LogName = 'Security' ID = $LockOutID } }ElseIf($PSCmdlet.ParameterSetName -eq 'ByUser'){ $user = Get-ADUser $Identity #Query event log $events = Get-WinEvent -ComputerName $PDCEmulator -FilterHashtable @{ LogName = 'Security' ID = $LockOutID } | Where-Object {$_.Properties[0].Value -eq $user.SamAccountName} } ForEach($event in $events){ [pscustomobject]@{ UserName = $event.Properties[0].Value CallerComputer = $event.Properties[1].Value TimeStamp = $event.TimeCreated } } } End{} } #Usage Get-ADUserLockouts #Single user Get-ADUser 'jesse.pinkman' | Get-ADUserLockouts Now we come to the incorrectly entered passwords. These events are logged in the Windows event logs with the ID 4625. #Prep work for bad passwords - Event ID $badPwId = 4625 #Get the events from the PDC $events = Get-WinEvent -ComputerName $PDCEmulator -FilterHashtable @{ LogName = 'Security' ID = $badPwId } #Correlate the logon types $LogonType = @{ '2' = 'Interactive' '3' = 'Network' '4' = 'Batch' '5' = 'Service' '7' = 'Unlock' '8' = 'Networkcleartext' '9' = 'NewCredentials' '10' = 'RemoteInteractive' '11' = 'CachedInteractive' } #Format the properties ForEach($event in $events){ [pscustomobject]@{ TargetAccount = $event.properties.Value[5] LogonType = $LogonType["$($event.properties.Value[10])"] CallingComputer = $event.Properties.Value[13] IPAddress = $event.Properties.Value[19] TimeStamp = $event.TimeCreated } } #Bring it all together in a function Function Get-ADUserBadPasswords { [CmdletBinding( DefaultParameterSetName = 'All' )] Param ( [Parameter( ValueFromPipeline = $true, ParameterSetName = 'ByUser' )] [Microsoft.ActiveDirectory.Management.ADUser]$Identity ) Begin { $badPwId = 4625 $PDCEmulator = (Get-ADDomain).PDCEmulator $LogonType = @{ '2' = 'Interactive' '3' = 'Network' '4' = 'Batch' '5' = 'Service' '7' = 'Unlock' '8' = 'Networkcleartext' '9' = 'NewCredentials' '10' = 'RemoteInteractive' '11' = 'CachedInteractive' } } Process { If($PSCmdlet.ParameterSetName -eq 'All'){ #Query event log $events = Get-WinEvent -ComputerName $PDCEmulator -FilterHashtable @{ LogName = 'Security' ID = $badPwId } }ElseIf($PSCmdlet.ParameterSetName -eq 'ByUser'){ $user = Get-ADUser $Identity #Query event log $events = Get-WinEvent -ComputerName $PDCEmulator -FilterHashtable @{ LogName = 'Security' ID = $badPwId } | Where-Object {$_.Properties[5].Value -eq $user.SamAccountName} } ForEach($event in $events){ [pscustomobject]@{ TargetAccount = $event.properties.Value[5] LogonType = $LogonType["$($event.properties.Value[10])"] CallingComputer = $event.Properties.Value[13] IPAddress = $event.Properties.Value[19] TimeStamp = $event.TimeCreated } } } End{} } #Usage Get-ADUserBadPasswords | Format-Table #Single account Get-ADUser administrator | Get-ADUserBadPasswords | Format-Table I hope that this information is helpful to you and that you have been given a good "little" foundation. This article/information is by no means complete and exhaustive. But I still hope that this information is helpful to you. Thank you for taking the time to read the article. Happy Hunting, Tom Wechsler P.S. All scripts (#PowerShell, Azure CLI, #Terraform, #ARM) that I use can be found on github! https://github.com/tomwechslerActive Directory Advanced Threat Hunting - Compare GPOs with the Security Compliance Toolkit
Dear Microsoft Active Directory friends, Even in the age of digital transformation, group policy settings (still) play a crucial role in maintaining network security and compliance. Advanced Hunting, an advanced technique for monitoring and analyzing these settings, is an indispensable tool for administrators. This method makes it possible to gain in-depth insights into the configuration and security situation of Windows networks. By using specific tools and scripts, professionals can detect security vulnerabilities, identify configuration errors and ensure that all group policies meet the highest security and compliance requirements. This article introduces the concept of Advanced Hunting for Group Policy settings and how it can transform management and security in IT infrastructures. Do we now need additional software and/or expensive tools? No, all we need is a little time, curiosity and the "Security Compliance Toolkit", which Microsoft is making available to us free of charge (thanks to Microsoft at this point). But first let's take a closer look at the MITRE techniques and the relevant Windows Event IDs. Before we start analyzing the group policy settings. We start with a list of MITRE techniques: Domain Policy Modification https://attack.mitre.org/techniques/T1484/ Domain Policy Modification: Group Policy Modification https://attack.mitre.org/techniques/T1484/001/ Group Policy Discovery https://attack.mitre.org/techniques/T1615/ Domain Policy Modification: Domain Trust Modification https://attack.mitre.org/techniques/T1484/002/ Unsecured Credentials: Group Policy Preferences https://attack.mitre.org/techniques/T1552/006/ The Windows Event ID's for the MITRE techniques: Domain Policy Modification 4739(S): Domain Policy was changed https://learn.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4739 Group Policy Discovery Appendix L: Events to Monitor https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/plan/appendix-l--events-to-monitor Domain Policy Modification: Domain Trust Modification 4716(S): Trusted domain information was modified https://learn.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4716 Compare the Default Domain Controllers Policy with the security baselines using the Policy Analyzer! So that we can compare the Default Domain Controllers Policy, we create a backup: Security Compliance Toolkit and Baselines can be downloaded here: https://www.microsoft.com/en-us/download/details.aspx?id=55319 We need the necessary tools and baselines: Extract the files: From the Windows-Server-2022-Security-Baseline-FINAL folder, copy the following file: Paste the file in the Policy Analyzer folder: Open the Policy Analyzer: NOTE: If you have a low screen resolution you may not be able to see the bottom part of the application. It is important that you see the bottom part so that you can adjust the path to the policy rule sets (see red marker). Now we have to add the default domain controller policy: Click on the import button: Give it a name and then click on safe: Now you can compare the policy with the security baseline: HAPPY COMPARING! If you want to examine your Active Directory with PowerShell, you will find a "small" compilation of various PowerShell scripts in the following link: https://github.com/tomwechsler/Active_Directory_Advanced_Threat_Hunting/tree/main/PowerShell NOTE: Before using these scripts, make sure that you have the necessary authorizations. This should always be in writing. Although the scripts do not change any settings or manipulate the system, it is your responsibility how you use these scripts! I hope that this information is helpful to you and that you have been given a good "little" foundation. This article/information is by no means complete and exhaustive. But I still hope that this information is helpful to you. Thank you for taking the time to read the article. Happy Comparing and Hunting, Tom Wechsler P.S. All scripts (#PowerShell, Azure CLI, #Terraform, #ARM) that I use can be found on github! https://github.com/tomwechslerRe: Company Portal not installed (device based install with pre provisioning deployment)
Hi Florian, I have the suspicion that it is because the primary user is missing on the end device in the Intune portal. The graphic says "no user", the company portal always "wants" a primary user. It could possibly be due to this situation. Here is a link to a Microsoft article: https://learn.microsoft.com/en-us/mem/intune/remote-actions/find-primary-user I hope this helps you? Regards, TomRe: Company Portal not installed (device based install with pre provisioning deployment)
Have you also removed the device (object) from the tenant (Autopilot as well as in Intune)? I assume that the initial deployment of the device saves the installation status from the company portal in Intune. So that during the second deployment Intune reverts to the information that the enterprise portal app is already installed. Regards, TomRe: Need help understanding Disks
Hello, When you create a VM in Azure, you do not necessarily have to add an additional disk. When you select the size in Azure, the operating system hard disk is assigned accordingly. Of course, you can add an additional hard disk if you want to save files on this hard disk. Kind regards, Tom
