In der sich ständig weiterentwickelnden IT-Welt sind das Monitoring und die Analyse von Ereignisprotokollen essenziell für die Aufrechterhaltung des Systemzustands, die Diagnose von Problemen und die Gewährleistung der Sicherheits-Compliance.
Ereignisprotokolle sind eine ergiebige Quelle für Informationen über den Zustand und das Verhalten von Systemen, und die Möglichkeit, diese Protokolle effizient zu durchsuchen und zu filtern, kann die Fähigkeit eines IT-Experten zur Verwaltung seiner Infrastruktur erheblich verbessern.
In diesem Blogbeitrag besprechen wir, wie Sie PowerShell für effiziente Ereignisprotokollsuchen verwenden können. Genauer gesagt wird heute ein PowerShell-Skript vorgestellt, das die Suche in Ereignisprotokollen vereinfacht und das Auffinden bestimmter Ereignisse anhand von Kriterien wie Ereignisprotokollnamen, Quelle, Ereignis-ID usw. erleichtert.
Die Bedeutung des Ereignisprotokollmanagements in der IT
Ereignisprotokolle sind Aufzeichnungen von System-, Sicherheits- und Anwendungsereignissen auf einem Computer. Diese Protokolle sind unverzichtbar für die Fehlerbehebung, die Überprüfung von Sicherheitsvorfällen und die Compliance.
Für Managed Service Provider (MSPs) und IT-Experten ist die Möglichkeit, diese Protokolle schnell und genau zu durchsuchen, ausschlaggebend. Ohne effiziente Tools kann diese Aufgabe mühsam werden, vor allem, wenn es um eine große Anzahl von Systemen oder komplexe Umgebungen geht.
PowerShell, eine von Microsoft entwickelte leistungsstarke Skriptsprache, bietet solide Funktionen für die Interaktion mit Ereignisprotokollen. Das Skript, das wir heute besprechen, wurde entwickelt, um den Suchprozess zu optimieren und es IT-Experten zu ermöglichen, relevante Ereignisse in der Ereignisanzeige schnell zu finden.
Das Skript:
#Requires -Version 5.1
<#
.SYNOPSIS
Search for specific events in Event Viewer based on the event log they were in, the source of the event, or the specific event IDs used. One of these three options is required for the search.
.DESCRIPTION
Search for specific events in Event Viewer based on the event log they were in, the source of the event, or the specific event IDs used. One of these three options is required for the search.
.EXAMPLE
-EventLogName "Application"
Matching Events Found!
LogName : Application
ProviderName : Microsoft-Windows-Security-SPP
Id : 16384
TimeCreated : 4/4/2024 10:00:48 AM
Message : Successfully scheduled Software Protection service for re-start at 2024-04-04T21:19:48Z. Reason: Rul...
LogName : Application
ProviderName : Microsoft-Windows-Security-SPP
Id : 16394
TimeCreated : 4/4/2024 10:00:17 AM
Message : Offline downlevel migration succeeded.
LogName : Application
ProviderName : Microsoft-Windows-Security-SPP
Id : 16384
TimeCreated : 4/4/2024 9:59:59 AM
Message : Successfully scheduled Software Protection service for re-start at 2024-04-04T21:19:59Z. Reason: Rul...
PARAMETER: -EventLogName "Application"
Specify the name of the Event Log from which to retrieve events.
PARAMETER: -EventLogSource "Microsoft-Windows-Kernel-General"
Determines the source of the events to retrieve.
PARAMETER: -EventLogMessage "Alert"
Filters events by the text contained in the event's message.
PARAMETER: -EventIDs "12, 13, 6008"
A comma-separated list of event IDs to include in the search.
PARAMETER: -excludeEventIDs "13"
A comma-separated list of event IDs to exclude from the search.
PARAMETER: -StartDate "12/24/2021"
Defines the start date and time for the event search. Events logged before this time will not be included in the results.
PARAMETER: -EndDate "12/29/2021"
Sets the end date and time for the event search. Events logged after this time will not be included.
PARAMETER: -MultilineCustomField "replaceMeWithAcustomFieldName"
Specify the name of a multiline custom field to optionally store the search results in. Leave blank to not set a multiline field.
PARAMETER: -WysiwygCustomField "replaceMeWithACustomFieldName"
Specify the name of a WYSIWYG custom field to optionally store the search results in. Leave blank to not set a WYSIWYG field.
.NOTES
Minimum OS Architecture Supported: Windows 10, Windows Server 2016
Release Notes: Initial Release
By using this script, you indicate your acceptance of the following legal terms as well as our Terms of Use at https://ninjastage2.wpengine.com/terms-of-use.
Ownership Rights: NinjaOne owns and will continue to own all right, title, and interest in and to the script (including the copyright). NinjaOne is giving you a limited license to use the script in accordance with these legal terms.
Use Limitation: You may only use the script for your legitimate personal or internal business purposes, and you may not share the script with another party.
Republication Prohibition: Under no circumstances are you permitted to re-publish the script in any script library or website belonging to or under the control of any other software provider.
Warranty Disclaimer: The script is provided “as is” and “as available”, without warranty of any kind. NinjaOne makes no promise or guarantee that the script will be free from defects or that it will meet your specific needs or expectations.
Assumption of Risk: Your use of the script is at your own risk. You acknowledge that there are certain inherent risks in using the script, and you understand and assume each of those risks.
Waiver and Release: You will not hold NinjaOne responsible for any adverse or unintended consequences resulting from your use of the script, and you waive any legal or equitable rights or remedies you may have against NinjaOne relating to your use of the script.
EULA: If you are a NinjaOne customer, your use of the script is subject to the End User License Agreement applicable to you (EULA).
#>
[CmdletBinding()]
param (
[Parameter()]
[String]$EventLogName,
[Parameter()]
[String]$EventLogSource,
[Parameter()]
[String]$EventLogMessage,
[Parameter()]
[String]$EventIDs,
[Parameter()]
[String]$ExcludeEventIDs,
[Parameter()]
[datetime]$StartDate,
[Parameter()]
[datetime]$EndDate,
[Parameter()]
[String]$MultilineCustomField,
[Parameter()]
[String]$WysiwygCustomField
)
begin {
# Set parameters using dynamic script variables.
if ($env:eventLogName -and $env:eventLogName -notlike "null") { $EventLogName = $env:eventLogName }
if ($env:eventLogSource -and $env:eventLogSource -notlike "null") { $EventLogSource = $env:eventLogSource }
if ($env:eventLogMessage -and $env:eventLogMessage -notlike "null") { $EventLogMessage = $env:eventLogMessage }
if ($env:eventIds -and $env:eventIds -notlike "null") { $EventIDs = $env:eventIds }
if ($env:excludeEventIds -and $env:excludeEventIds -notlike "null") { $ExcludeEventIDs = $env:excludeEventIds }
if ($env:eventStart -and $env:eventStart -notlike "null") { $StartDate = $env:eventStart }
if ($env:eventEnd -and $env:eventEnd -notlike "null") { $EndDate = $env:eventEnd }
if ($env:multilineCustomFieldName -and $env:multilineCustomFieldName -notlike "null") { $MultilineCustomField = $env:multilineCustomFieldName }
if ($env:wysiwygCustomFieldName -and $env:wysiwygCustomFieldName -notlike "null") { $WysiwygCustomField = $env:wysiwygCustomFieldName }
# Check if both StartDate and EndDate are provided and if StartDate is earlier than EndDate
if (($StartDate -and $EndDate) -and $StartDate -gt $EndDate) {
Write-Host -Object "[Error] Start date cannot be earlier than end date!"
exit 1
}
# Verify that WysiwygField and MultiLineField are not the same, exiting with an error if they are.
if ($WysiwygCustomField -and $MultilineCustomField -and ($WysiwygCustomField -eq $MultilineCustomField)) {
Write-Host -Object "[Error] Wysiwyg Field and Multiline Field are the same! Custom fields cannot be the same type."
Write-Host -Object "https://ninjarmm.zendesk.com/hc/en-us/articles/18601842971789-Custom-Fields-by-Type-and-Functionality"
exit 1
}
# Ensure that at least one of Event ID, Event Log Name, or Event Source is provided for the query
if (!$EventIDs -and !$EventLogName -and !$EventLogSource) {
Write-Host -Object "[Error] You must provide either an Event ID, Event Log Name or Event Source."
exit 1
}
# Trimming trailing spaces.
if ($EventLogName) {
$EventLogName = $EventLogName.Trim()
}
# Retrieve and sort all event log names available on the system
$EventLogNamesOnSystem = Get-WinEvent -ListLog * -ErrorAction SilentlyContinue | Sort-Object LogName
# Check if the provided EventLogName exists in the system's event logs
if ($EventLogName -and ($EventLogNamesOnSystem).LogName -notcontains $EventLogName) {
# If not found, print an error message and a list of valid event log names, then exit the script
Write-Host -Object "[Error] Event Log '$EventLogName' doesn't exist! See the list below for valid event log names."
Write-Host -Object "### Valid Event Log Names ###"
$EventLogNamesOnSystem | Select-Object -ExpandProperty LogName | Write-Host
exit 1
}
$InvalidEventSourceCharacters = "[\\/<>&`"%\|']"
if ($EventLogSource) {
if ($EventLogSource -match $InvalidEventSourceCharacters) {
Write-Host -Object "[Error] Event Log Source '$EventLogSource' contains an invalid character!"
exit 1
}
if ($EventLogSource.Length -gt 255) {
Write-Host -Object "[Error] Event Log Source '$EventLogSource' is too large to be an event source!"
exit 1
}
# Trims the event log source for trailing spaces
$EventLogSource = $EventLogSource.Trim()
}
# Prepare a list to hold valid event IDs to search for
$EventIdsToSearch = New-Object System.Collections.Generic.List[int]
# Process the input event IDs, removing any that are not purely numerical
if ($EventIDs -and $EventIDs -match ",") {
# If multiple event IDs are provided and separated by commas, split them
$EventIDs -split "," | ForEach-Object {
$EventId = $_.Trim()
# Validate each event ID to ensure it's numerical
if ($EventId -match '[a-zA-Z]|\W') {
# If not, print an error and skip adding this ID to the list
Write-Host "[Error] Event ID '$EventId' is not a valid event id. Removing it from the search."
$ExitCode = 1
return
}
# Check size of event id
if ([long]$EventId -gt 65535 -or [long]$EventId -lt 0) {
Write-Host "[Error] Event ID '$EventId' is not a valid event id. Event ID's must be less than or equal to 65535 and greater than or equal to 0. Removing it from the search."
$ExitCode = 1
return
}
# Add the validated event ID to the list
$EventIdsToSearch.Add($EventId)
}
}
elseif ($EventIDs) {
$EventId = $EventIDs.Trim()
# Handle a single event ID input
if ($EventId -match '[a-zA-Z]|\W') {
Write-Host "[Error] Event ID '$EventId' is not a valid event id. Removing it from the search."
$ExitCode = 1
}
elseif ([long]$EventId -gt 65535 -or [long]$EventId -lt 0) {
Write-Host "[Error] Event ID '$EventId' is not a valid event id. Event ID's must be less than or equal to 65535 and greater than or equal to 0. Removing it from the search."
$ExitCode = 1
}
else {
$EventIdsToSearch.Add($EventId)
}
}
# Prepare a list to hold event IDs that should be excluded from the search
$EventsToExclude = New-Object System.Collections.Generic.List[int]
# Similar process for excluded event IDs as regular event IDs
if ($ExcludeEventIDs -and $ExcludeEventIDs -match ",") {
$ExcludeEventIDs -split "," | ForEach-Object {
$ExcludeEventId = $_.Trim()
if ($ExcludeEventId -match '[a-zA-Z]|\W') {
Write-Host "[Error] Event ID '$ExcludeEventId' is not a valid event id. Removing it from the exclusions."
$ExitCode = 1
return
}
if ([long]$ExcludeEventId -gt 65535 -or [long]$ExcludeEventId -lt 0) {
Write-Host "[Error] Event ID '$ExcludeEventId' is not a valid event id. Event ID's must be less than or equal to 65535 and greater than or equal to 0. Removing it from the exclusions."
$ExitCode = 1
return
}
$EventsToExclude.Add($ExcludeEventId)
}
}
elseif ($ExcludeEventIDs) {
$ExcludeEventId = $ExcludeEventIDs.Trim()
if ($ExcludeEventId -match '[a-zA-Z]|\W') {
Write-Host "[Error] Event ID '$ExcludeEventId' is not a valid event id. Removing it from the exclusions."
$ExitCode = 1
}
elseif ([long]$ExcludeEventId -gt 65535 -or [long]$ExcludeEventId -lt 0) {
Write-Host "[Error] Event ID '$ExcludeEventId' is not a valid event id. Event ID's must be less than or equal to 65535 and greater than or equal to 0. Removing it from the exclusions."
$ExitCode = 1
}
else {
$EventsToExclude.Add($ExcludeEventId)
}
}
# Check if there are any event IDs to exclude and if the list of event IDs to search for is not empty.
if ($EventsToExclude.Count -gt 0 -and $EventIdsToSearch.Count -gt 0) {
$EventsToExclude | ForEach-Object {
# Check if the current event ID from the exclusion list is also in the list of event IDs to search for.
if ($EventIdsToSearch -contains $_) {
Write-Warning "Event ID $_ has been specified for both inclusion and exclusion. It will be excluded."
}
}
}
# Check if there's no valid event ID, log name, or log source provided and exit if true
if ($EventIdsToSearch.Count -eq 0 -and !$EventLogName -and !$EventLogSource) {
Write-Host "[Error] No valid Event ID given and no Event Log Name or Event Log Source given."
exit 1
}
# Handy function to set a custom field.
function Set-NinjaProperty {
[CmdletBinding()]
Param(
[Parameter(Mandatory = $True)]
[String]$Name,
[Parameter()]
[String]$Type,
[Parameter(Mandatory = $True, ValueFromPipeline = $True)]
$Value,
[Parameter()]
[String]$DocumentName
)
$Characters = $Value | Out-String | Measure-Object -Character | Select-Object -ExpandProperty Characters
if ($Characters -ge 200000) {
throw [System.ArgumentOutOfRangeException]::New("Character limit exceeded, value with $Characters characters is greater than or equal to 200,000 characters.")
}
# If we're requested to set the field value for a Ninja document we'll specify it here.
$DocumentationParams = @{}
if ($DocumentName) { $DocumentationParams["DocumentName"] = $DocumentName }
# This is a list of valid fields that can be set. If no type is given, it will be assumed that the input doesn't need to be changed.
$ValidFields = "Attachment", "Checkbox", "Date", "Date or Date Time", "Decimal", "Dropdown", "Email", "Integer", "IP Address", "MultiLine", "MultiSelect", "Phone", "Secure", "Text", "Time", "URL", "WYSIWYG"
if ($Type -and $ValidFields -notcontains $Type) { Write-Warning "$Type is an invalid type! Please check here for valid types. https://ninjarmm.zendesk.com/hc/en-us/articles/16973443979789-Command-Line-Interface-CLI-Supported-Fields-and-Functionality" }
# The field below requires additional information to be set
$NeedsOptions = "Dropdown"
if ($DocumentName) {
if ($NeedsOptions -contains $Type) {
# We'll redirect the error output to the success stream to make it easier to error out if nothing was found or something else went wrong.
$NinjaPropertyOptions = Ninja-Property-Docs-Options -AttributeName $Name @DocumentationParams 2>&1
}
}
else {
if ($NeedsOptions -contains $Type) {
$NinjaPropertyOptions = Ninja-Property-Options -Name $Name 2>&1
}
}
# If an error is received it will have an exception property, the function will exit with that error information.
if ($NinjaPropertyOptions.Exception) { throw $NinjaPropertyOptions }
# The below type's require values not typically given in order to be set. The below code will convert whatever we're given into a format ninjarmm-cli supports.
switch ($Type) {
"Checkbox" {
# While it's highly likely we were given a value like "True" or a boolean datatype it's better to be safe than sorry.
$NinjaValue = [System.Convert]::ToBoolean($Value)
}
"Date or Date Time" {
# Ninjarmm-cli expects the GUID of the option to be selected. Therefore, the given value will be matched with a GUID.
$Date = (Get-Date $Value).ToUniversalTime()
$TimeSpan = New-TimeSpan (Get-Date "1970-01-01 00:00:00") $Date
$NinjaValue = $TimeSpan.TotalSeconds
}
"Dropdown" {
# Ninjarmm-cli is expecting the guid of the option we're trying to select. So we'll match up the value we were given with a guid.
$Options = $NinjaPropertyOptions -replace '=', ',' | ConvertFrom-Csv -Header "GUID", "Name"
$Selection = $Options | Where-Object { $_.Name -eq $Value } | Select-Object -ExpandProperty GUID
if (-not $Selection) {
throw [System.ArgumentOutOfRangeException]::New("Value is not present in dropdown")
}
$NinjaValue = $Selection
}
default {
# All the other types shouldn't require additional work on the input.
$NinjaValue = $Value
}
}
# We'll need to set the field differently depending on if its a field in a Ninja Document or not.
if ($DocumentName) {
$CustomField = Ninja-Property-Docs-Set -AttributeName $Name -AttributeValue $NinjaValue @DocumentationParams 2>&1
}
else {
$CustomField = $NinjaValue | Ninja-Property-Set-Piped -Name $Name 2>&1
}
if ($CustomField.Exception) {
throw $CustomField
}
}
function Test-IsElevated {
$id = [System.Security.Principal.WindowsIdentity]::GetCurrent()
$p = New-Object System.Security.Principal.WindowsPrincipal($id)
$p.IsInRole([System.Security.Principal.WindowsBuiltInRole]::Administrator)
}
if (!$ExitCode) {
$ExitCode = 0
}
}
process {
# Check if the script is running with elevated (Administrator) privileges
if (!(Test-IsElevated)) {
# If not, display an error message and exit with status code 1
Write-Host -Object "[Error] Access Denied. Please run with Administrator privileges."
exit 1
}
# Prepare a list to hold event log names to search for
$EventLogNamesToSearch = New-Object System.Collections.Generic.List[string]
# If no event log name was required we'll search all the event
if (!$EventLogName) {
$EventLogNamesOnSystem | Where-Object { $_.RecordCount -gt 0 } | Select-Object -ExpandProperty LogName | ForEach-Object {
$EventLogNamesToSearch.Add($_)
}
}
else {
$EventLogNamesToSearch.Add($EventLogName)
}
# Create XML object.
[xml]$XML = New-Object System.Xml.XmlDocument
# Add QueryList element to xml.
$QueryList = $XML.CreateElement("QueryList")
$QueryList = $XML.AppendChild($QueryList)
# Create query element and nest it under QueryList.
$Query = $XML.CreateElement("Query")
$Query.SetAttribute("Id", "0")
$Query = $QueryList.AppendChild($Query)
# Foreach event log to search we're going to create a select element.
$EventLogNamesToSearch | ForEach-Object {
# We'll start each loop by selecting the query element to add to.
$Query = $XML.SelectSingleNode("//Query")
# The select element starts off with the event log to search.
$Select = $XML.CreateElement("Select")
$Select.SetAttribute("Path", "$_")
# Reset the inner text between runnings
$XMLInnerText = $Null
# The inner text of each element (<Element1>InnerText</Element1>) will need to be built differently depending on the parameters.
if ($EventLogSource) {
$XMLInnerText = "*[System[Provider[@Name='$EventLogSource']]]"
}
# If we're given a select number of event id's to search we'll filter them here.
if ($EventIdsToSearch.Count -gt 0) {
$EventIDSearchText = $Null
$EventIdsToSearch | ForEach-Object {
# We may have been given one event id or more than one.
if ($EventIDSearchText) {
$EventIDSearchText = "$EventIDSearchText or EventID=$_"
}
else {
$EventIDSearchText = "EventID=$_"
}
}
# We'll replace the two ending brackets with our given search text
if ($XMLInnerText) {
$XMLInnerText = $XMLInnerText -replace ']]$', " and ($EventIDSearchText)]]"
}
else {
$XMLInnerText = "*[System[($EventIDSearchText)]]"
}
}
# If we're also asked to filter based on the date the event was created we'll create the filter text here.
if ($StartDate -or $EndDate) {
$DateFilter = $Null
if ($StartDate) {
$XMLstartDate = Get-Date $StartDate -Format "yyyy-MM-ddTHH:mm:ss"
# PowerShell will convert the < or > symbol for us when we go to save to the xml.
$DateFilter = "@SystemTime>='$XMLstartDate'"
}
# We may or may not have been given a start date.
if ($EndDate -and $DateFilter) {
$XMLendDate = Get-Date $EndDate -Format "yyyy-MM-ddTHH:mm:ss"
$DateFilter = "$DateFilter and @SystemTime<='$XMLendDate'"
}
elseif ($EndDate) {
$XMLendDate = Get-Date $EndDate -Format "yyyy-MM-ddTHH:mm:ss"
$DateFilter = "@SystemTime<='$XMLendDate'"
}
# Replace the last two closing brackets and add our filter text.
if($XMLInnerText){
$XMLInnerText = $XMLInnerText -replace ']]$', " and TimeCreated[$DateFilter]]]"
}else{
$XMLInnerText = "*[System[TimeCreated[$DateFilter]]]"
}
}
# If no filters were given (other than the event log name) we'll need to select everything in that log
if(!$XMLInnerText){
$XMLInnerText = "*"
}
# Save our filter text to the select statement
$Select.InnerText = $XMLInnerText
# Append our select statement to our xml file
$Query.AppendChild($Select) | Out-Null
}
# Search for matching events using the XML filter
$MatchingEvents = Get-WinEvent -FilterXml $XML -ErrorAction SilentlyContinue
# Exclude events based on the excluded event IDs if any are specified
if ($EventsToExclude.Count -gt 0) {
$MatchingEvents = $MatchingEvents | Where-Object { $EventsToExclude -notcontains $_.ID }
}
# Exclude events that do not match the keywords you specified.
if ($EventLogMessage) {
$MatchingEvents = $MatchingEvents | Where-Object { $_.Message -like "*$EventLogMessage*" }
}
# If the event log message is larger than 100 characters trim it and add ...
if ($MatchingEvents) {
$MatchingEvents = $MatchingEvents | Select-Object LevelDisplayName, LogName, ProviderName, Id, TimeCreated, @{
Name = 'Message'
Expression = {
$Characters = $_.Message | Measure-Object -Character | Select-Object -ExpandProperty Characters
if ($Characters -gt 100) {
"$(($_.Message).SubString(0,100))(...)"
}
else {
$_.Message
}
}
}
# Sort the object by newest event to oldest
$MatchingEvents = $MatchingEvents | Sort-Object TimeCreated -Descending
}
# Set a Wysiwyg custom field if any matching events are found and it was requested.
if ($WysiwygCustomField -and $MatchingEvents) {
try {
Write-Host "Attempting to set Custom Field '$WysiwygCustomField'."
# Prepare the custom field output.
$CustomFieldValue = New-Object System.Collections.Generic.List[string]
# Convert the matching events into an html report.
$htmlTable = $MatchingEvents | Select-Object -Property LevelDisplayName, LogName, ProviderName, Id, TimeCreated, Message | ConvertTo-Html -Fragment
# Set color coding
$htmlTable = $htmlTable -replace "<tr><td>Verbose</td>", "<tr class=`"other`"><td>Verbose</td>"
$htmlTable = $htmlTable -replace "<tr><td>Warning</td>", "<tr class=`"warning`"><td>Warning</td>"
$htmlTable = $htmlTable -replace "<tr><td>Error</td>", "<tr class=`"danger`"><td>Error</td>"
$htmlTable = $htmlTable -replace "<tr><td>Critical Error</td>", "<tr class=`"danger`"><td>Critical Error</td>"
# Remove Level Display Name
$LevelDisplayNames = $MatchingEvents | Select-Object -Property LevelDisplayName -Unique
$LevelDisplayNames | ForEach-Object {
$htmlTable = $htmlTable -replace "<td>$([Regex]::Escape($_.LevelDisplayName))</td>"
}
$htmlTable = $htmlTable -replace "<th>LevelDisplayName</th>"
# Add the newly created html into the custom field output.
$CustomFieldValue.Add($htmlTable)
# Check that the output complies with the hard character limits.
$Characters = $CustomFieldValue | Out-String | Measure-Object -Character | Select-Object -ExpandProperty Characters
if ($Characters -ge 199500) {
Write-Warning "200,000 Character Limit has been reached! Trimming output until the character limit is satisified..."
# If it doesn't comply with the limits we'll need to recreate it with some adjustments.
$i = 0
do {
# Recreate the custom field output starting with a warning that we truncated the output.
$CustomFieldValue = New-Object System.Collections.Generic.List[string]
$CustomFieldValue.Add("<h1>This info has been truncated to accommodate the 200,000 character limit.</h1>")
# The custom field information is sorted from newest to oldest. We'll remove the oldest first by flipping the array upside down.
[array]::Reverse($htmlTable)
# If the next entry is a row we'll delete it.
if ($htmlTable[$i] -match '<tr><td>' -or $htmlTable[$i] -match '<tr class=') {
$htmlTable[$i] = $null
}
$i++
# We'll flip the array back to right side up.
[array]::Reverse($htmlTable)
# Add it back to the output.
$CustomFieldValue.Add($htmlTable)
# Check that we now comply with the character limit. If not restart the do loop.
$Characters = $CustomFieldValue | Out-String | Measure-Object -Character | Select-Object -ExpandProperty Characters
}while ($Characters -ge 199500)
}
# Set the custom field.
Set-NinjaProperty -Name $WysiwygCustomField -Value $CustomFieldValue
Write-Host "Successfully set Custom Field '$WysiwygCustomField'!"
}
catch {
Write-Host "[Error] $($_.Exception.Message)"
$ExitCode = 1
}
}
# Set a multiline custom field if any matching events are found and it was requested.
if ($MultilineCustomField -and $MatchingEvents) {
try {
Write-Host "Attempting to set Custom Field '$MultilineCustomField'."
$CustomFieldValue = New-Object System.Collections.Generic.List[string]
# We don't want to edit the matching Events array if we have to truncate later so we'll create a duplicate here.
$CustomFieldList = $MatchingEvents | Select-Object -Property LogName, ProviderName, Id, TimeCreated, Message
# Format the matching items into a nice list with the relevant properties.
$CustomFieldValue.Add(($CustomFieldList | Format-List -Property LogName, ProviderName, Id, TimeCreated, Message | Out-String))
# Check that the output complies with the hard character limits.
$Characters = $CustomFieldValue | Out-String | Measure-Object -Character | Select-Object -ExpandProperty Characters
if ($Characters -ge 9500) {
Write-Warning "10,000 Character Limit has been reached! Trimming output until the character limit is satisified..."
# If it doesn't comply with the limits we'll need to recreate it with some adjustments.
$i = 0
do {
# Recreate the custom field output starting with a warning that we truncated the output.
$CustomFieldValue = New-Object System.Collections.Generic.List[string]
$CustomFieldValue.Add("This info has been truncated to accommodate the 10,000 character limit.")
# The custom field information is sorted from newest to oldest. We'll remove the oldest events first by flipping the array upside down.
[array]::Reverse($CustomFieldList)
# Remove the next item which in this case will be the oldest item.
$CustomFieldList[$i] = $null
$i++
# We'll flip the array back to right side up.
[array]::Reverse($CustomFieldList)
# Add it back to the output.
$CustomFieldValue.Add(($CustomFieldList | Format-List -Property LogName, ProviderName, Id, TimeCreated, Message | Out-String))
# Check that we now comply with the character limit. If not restart the do loop.
$Characters = $CustomFieldValue | Out-String | Measure-Object -Character | Select-Object -ExpandProperty Characters
}while ($Characters -ge 9500)
}
Set-NinjaProperty -Name $MultilineCustomField -Value $CustomFieldValue
Write-Host "Successfully set Custom Field '$MultilineCustomField'!"
}
catch {
Write-Host "[Error] $($_.Exception.Message)"
$ExitCode = 1
}
}
# If any matching events were found output them into the activity log.
if ($MatchingEvents) {
Write-Host "Matching Events Found!"
$MatchingEvents | Format-List LogName, ProviderName, Id, TimeCreated, Message | Out-String | Write-Host
}
else {
Write-Host "No matching events found!"
}
exit $ExitCode
}
end {
}
Das PowerShell-Skript verstehen
Dieses PowerShell-Skript ist ein vielseitiges Tool, mit dem Benutzer:innen auf der Grundlage verschiedener Kriterien nach bestimmten Ereignissen in der Ereignisanzeige suchen können. Das Skript kann Ereignisse nach Protokollnamen, Quelle, Ereignis-ID, Nachrichteninhalt und Datumsbereich filtern. Außerdem bietet es Optionen, um bestimmte Ereignis-IDs von der Suche auszuschließen und die Ergebnisse in benutzerdefinierten Feldern zu speichern.
Hier finden Sie eine detaillierte Aufschlüsselung der Funktionsweise des Skripts:
1. Parameter und Umgebungsvariablen:
- Das Skript beginnt mit dem Festlegen von Parametern, mit denen die Benutzer:innen ihre Suchkriterien definieren können, z. B. EventLogName, EventLogSource, EventIDs, StartDate und EndDate. Es unterstützt auch Umgebungsvariablen für diese Parameter und ermöglicht so die Integration in andere Automatisierungsabläufe.
2. Validierung und Fehlerbehandlung:
- Das Skript enthält mehrere Ebenen der Validierung, um sicherzustellen, dass die Eingabeparameter korrekt sind. So wird beispielsweise geprüft, ob das angegebene Startdatum vor dem Enddatum liegt, und es wird sichergestellt, dass die Ereignis-IDs numerisch sind und innerhalb des zulässigen Bereichs liegen.
- Wenn die Parameter WysiwygCustomField und MultilineCustomField auf denselben Wert gesetzt sind, gibt das Skript einen Fehler aus, um widersprüchliche Konfigurationen zu verhindern.
3. Logik der Ereignisprotokollsuche:
- Das Skript erstellt eine XML-Abfrage, um Ereignisse anhand der angegebenen Kriterien zu filtern. Diese Abfrage wird dann mit dem cmdlet “Get-WinEvent” verwendet, um passende Ereignisse aus den angegebenen Protokollen abzurufen.
- Das Skript ermöglicht den Ausschluss bestimmter Ereignis-IDs und kann Ereignisse nach dem Inhalt der Nachricht filtern, wodurch es hochgradig anpassbar ist.
4. Benutzerdefinierte Feldeinstellung:
- Wenn passende Ereignisse gefunden werden, kann das Skript die Ergebnisse in benutzerdefinierten Feldern speichern, entweder als mehrzeiliges Textfeld oder als HTML-formatierter Bericht. Diese Funktion ist besonders nützlich für MSPs, die Ergebnisse dokumentieren oder die Berichterstattung automatisieren müssen.
5. Ausgabe und Sortierung:
- Das Skript gibt die Ergebnisse in einem lesbaren Format aus, sortiert sie nach dem Zeitpunkt der Erstellung der Ereignisse, vom neuesten bis zum ältesten. Außerdem werden lange Nachrichten gekürzt, um die Ausgabe nicht zu überladen.
Praktische Anwendungen des Skripts
Stellen Sie sich ein Szenario vor, in dem ein IT-Experte die Aufgabe hat, wiederkehrende Fehler auf mehreren Servern in einer Unternehmensumgebung zu identifizieren. Das manuelle Durchsuchen der Ereignisprotokolle auf jedem Server wäre zeitaufwändig und fehleranfällig.
Mithilfe dieses PowerShell-Skripts kann der IT-Mitarbeiter den Suchprozess automatisieren, Protokolle auf der Grundlage bestimmter Fehlerereignis-IDs filtern und die Ergebnisse auf einen bestimmten Zeitraum eingrenzen. Dieser Ansatz spart nicht nur Zeit, sondern verbessert auch die Genauigkeit, sodass das IT-Team Probleme schnell diagnostizieren und beheben kann.
Ein weiterer Anwendungsfall könnte die Überprüfung der Compliance sein. Ein MSP muss möglicherweise überprüfen, ob bestimmte Sicherheitsereignisse, wie z. B. erfolgreiche oder fehlgeschlagene Login-Versuche, in den von ihm verwalteten Systemen wie erwartet auftreten. Mit diesem Skript können diese Ereignisse extrahiert und Berichte erstellt werden, die die Compliance im Bereich Sicherheit belegen.
Vergleich von Ansätzen für die Suche im Ereignisprotokoll
Es gibt zwar mehrere Methoden zum Durchsuchen von Ereignisprotokollen, einschließlich der integrierten Ereignisanzeige-GUI oder anderer Tools von Drittanbietern, aber dieses PowerShell-Skript bietet deutliche Vorteile. Im Gegensatz zur manuellen Suche über die grafische Benutzeroberfläche kann dieses Skript automatisiert und in größere Arbeitsabläufe integriert werden. Darüber hinaus bietet PowerShell im Vergleich zu anderen Tools zahlreiche Anpassungsmöglichkeiten, sodass IT-Experten die Suchkriterien an ihre spezifischen Anforderungen anpassen können.
Häufig gestellte Fragen
F: Kann dieses Skript auf Systemen mit älteren Windows-Versionen verwendet werden?
A: Das Skript erfordert Windows PowerShell 5.1 und wird unter Windows 10 und Windows Server 2016 oder höher unterstützt.
F: Was passiert, wenn die Zeichengrenze beim Einrichten eines benutzerdefinierten Feldes überschritten wird?
A: Das Skript enthält eine Logik, um die Ausgabe zu kürzen, damit sie in die Zeichenbegrenzung passt. So wird sichergestellt, dass das Skript nicht an zu großen Datensätzen scheitert.
F: Ist es möglich, mit diesem Skript alle Ereignisprotokolle auf einem System zu durchsuchen?
A: Ja, wenn kein bestimmter Ereignisprotokollname angegeben wird, durchsucht das Skript alle verfügbaren Ereignisprotokolle auf dem System.
Auswirkungen auf die IT-Sicherheit
Die Verwendung von PowerShell für effiziente Ereignisprotokollsuchen hat erhebliche Auswirkungen auf die IT-Sicherheit. Indem verdächtige oder anomale Ereignisse schnell erkannt werden, können IT-Experten effektiver auf potenzielle Sicherheitsvorfälle reagieren. Die von diesem Skript gebotene Automatisierung verringert das Risiko menschlicher Fehler und stellt sicher, dass kritische Ereignisse nicht übersehen werden.
Best Practices für die Verwendung des Skripts
- Testen Sie das Skript immer in einer kontrollierten Umgebung, bevor Sie es in der Produktion bereitstellen.
- Verwenden Sie Umgebungsvariablen, um das Skript in größere Automatisierungsabläufe zu integrieren.
- Aktualisieren Sie das Skript regelmäßig, um neue Funktionen einzubauen oder potenzielle Sicherheitslücken zu schließen.
Abschließende Überlegungen
Eine effiziente Verwaltung von Ereignisprotokollen ist für die Aufrechterhaltung des Systemzustands, die Gewährleistung der Sicherheit und die Compliance unerlässlich. Dieses PowerShell-Skript bietet IT-Experten ein leistungsstarkes Tool zum Durchsuchen und Analysieren von Ereignisprotokollen, mit dem sie ihre Aufgaben effektiver erledigen können.
Für MSPs und IT-Teams, die mehrere Systeme verwalten, bietet NinjaOne eine komplette Suite von Tools, die das Monitoring und Management der IT-Infrastruktur weiter verstärken können. Wenn Sie dieses Skript in Ihre Arbeitsabläufe integrieren, können Sie die Suche in den Ereignisprotokollen optimieren und Ihre IT-Abläufe insgesamt verbessern.