Major Update to v1.9 pre-DerbyCon
This commit is contained in:
Eric Conrad
252
DeepBlue.ps1
252
DeepBlue.ps1
@ -25,7 +25,7 @@ https://github.com/sans-blue-team/DeepBlueCLI
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#>
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# DeepBlueCLI 0.4 Beta
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# DeepBlueCLI 1.9 pre-DerbyCon
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# Eric Conrad, Backshore Communications, LLC
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# deepblue <at> backshore <dot> net
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# Twitter: @eric_conrad
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@ -35,18 +35,27 @@ https://github.com/sans-blue-team/DeepBlueCLI
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param ([string]$file=$env:file,[string]$log=$env:log)
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function Main {
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# Set up the global variables
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$text="" # Temporary scratch pad variable to hold output text
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$minlength=1000 # Minimum length of command line to alert
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# Load cmd match regexes from csv file, ignore comments
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$regexes = Get-Content ".\regexes.txt" | Select-String '^[^#]' | ConvertFrom-Csv
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#$regexes
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# Load cmd whitelist regexes from csv file, ignore comments
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$whitelist = Get-Content ".\whitelist.txt" | Select-String '^[^#]' | ConvertFrom-Csv
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$logname=Check-Options $file $log
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"Processing the " + $logname + " log..."
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#"Processing the " + $logname + " log..."
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$filter=Create-Filter $file $logname
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$failedlogons=0 # Count of failed logons (Security event 4625)
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$maxfailedlogons=100 # Alert after this many failed logons
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$maxfailedlogons=25 # Alert after this many failed logons
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$failedlogins=@{} # HashTable of failed logins per user
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# Obfuscation variables:
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$minpercent=.65 # minimum percentage of alphanumeric and common symbols
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$maxbinary=.50 # Maximum percentage of zeros and ones to detect binary encoding
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#
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# Sysmon variables:
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# Check for unsigned EXEs/DLLs. This can be very chatty, so it's disabled.
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# Set $checkunsigned to 1 to enable:
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$checkunsigned = 0
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#
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# Get the events:
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try{
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$events = iex "Get-WinEvent $filter -ErrorAction Stop"
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@ -58,22 +67,35 @@ function Main {
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exit
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}
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ForEach ($event in $events) {
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$output="" # Final output text string
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# Custom reporting object:
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$obj = [PSCustomObject]@{
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Date = $event.TimeCreated
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Log = $logname
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EventID = $event.id
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Message = ""
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Command = ""
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Decoded = ""
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Results = ""
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}
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$eventXML = [xml]$event.ToXml()
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$servicecmd=0 # CLIs via service creation get extra checks, this defaults to 0 (no extra checks)
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if ($logname -eq "Security"){
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if ($event.id -eq 4688){
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# A new process has been created. (Command Line Logging)
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$commandline=$eventXML.Event.EventData.Data[8]."#text"
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$commandline=$eventXML.Event.EventData.Data[8]."#text" # Process Command Line
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$creator=$eventXML.Event.EventData.Data[13]."#text" # Creator Process Name
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if ($commandline){
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$output += (Check-Command $commandline $minlength $regexes $whitelist 0)
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Check-Command
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}
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}
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ElseIf ($event.id -eq 4720){
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# A user account was created.
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$username=$eventXML.Event.EventData.Data[0]."#text"
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$securityid=$eventXML.Event.EventData.Data[2]."#text"
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$output += " New user created: $username`n"
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$output += " - User SID: $securityid`n"
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$obj.Message = "New User Created"
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$obj.Results = "Username: $username`n"
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$obj.Results += "User SID: $securityid`n"
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Write-Output $obj
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}
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ElseIf(($event.id -eq 4728) -or ($event.id -eq 4732)){
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# A member was added to a security-enabled (global|local) group.
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@ -83,11 +105,12 @@ function Main {
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$username=$eventXML.Event.EventData.Data[0]."#text"
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$securityid=$eventXML.Event.EventData.Data[1]."#text"
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switch ($event.id){
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4728 {$output += " User added to global $groupname group`n"}
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4732 {$output += " User added to local $groupname group`n"}
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4728 {$obj.Message = "User added to global $groupname group"}
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4732 {$obj.Message = "User added to local $groupname group"}
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}
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$output += " - Username: $username`n"
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$output += " - User SID: $securityid`n"
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$obj.Results = "Username: $username`n"
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$obj.Results += "User SID: $securityid`n"
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Write-Output $obj
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}
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}
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ElseIf($event.id -eq 4625){
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@ -95,48 +118,63 @@ function Main {
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# Requires auditing logon failures
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# https://technet.microsoft.com/en-us/library/cc976395.aspx
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$username=$eventXML.Event.EventData.Data[5]."#text"
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$failedlogons += 1
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if($failedlogins.ContainsKey($username)){
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$count=$failedlogins.Get_Item($username)
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$failedlogins.Set_Item($username,$count+1)
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}
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Else{
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$failedlogins.Set_Item($username,1)
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}
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}
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}
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ElseIf ($logname -eq "System"){
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if ($event.id -eq 7045){
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# A service was installed in the system.
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$servicename=$eventXML.Event.EventData.Data[0]."#text"
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#$servicename
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$commandline=$eventXML.Event.EventData.Data[1]."#text"
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# Check for suspicious service name
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$text = (Check-Regex $servicename $regexes 1)
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$text = (Check-Regex $servicename 1)
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if ($text){
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$output += " Service created, service name: $servicename`n"
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$output += $text
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$obj.Message = "New Service Created"
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$obj.Command = $commandline
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$obj.Results = "Service name: $servicename`n"
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$obj.Results +=$text
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Write-Output $obj
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}
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# Check for suspicious cmd
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$commandline=$eventXML.Event.EventData.Data[1]."#text"
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if ($commandline){
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$output += (Check-Command $commandline $minlength $regexes $whitelist 1)
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$servicecmd=1 # CLIs via service creation get extra checks
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Check-Command
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}
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}
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ElseIf ($event.id -eq 7030){
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# The ... service is marked as an interactive service. However, the system is configured
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# to not allow interactive services. This service may not function properly.
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$servicename=$eventXML.Event.EventData.Data."#text"
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$output += " Interactive service warning, service name: $servicename`n"
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$obj.Message = "Interactive service warning"
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$obj.Results = "Service name: $servicename`n"
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$obj.Results += "Malware (and some third party software) trigger this warning"
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# Check for suspicious service name
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$output += (Check-Regex $servicename $regexes 1)
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$servicecmd=1 # CLIs via service creation get extra check
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$obj.Results += (Check-Regex $servicename 1)
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Write-Output $obj
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}
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ElseIf ($event.id -eq 7036){
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# The ... service entered the stopped|running state.
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$servicename=$eventXML.Event.EventData.Data[0]."#text"
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$text = (Check-Regex $servicename $regexes 1)
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$text = (Check-Regex $servicename 1)
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if ($text){
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$output += " " + $event.Message + "`n"
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$output += $text
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$obj.Message = "Suspicious Service Name"
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$obj.Results = "Service name: $servicename`n"
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$obj.Results += $text
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Write-Output $obj
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}
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}
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}
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ElseIf ($logname -eq "Application"){
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if (($event.id -eq 2) -and ($event.Providername -eq "EMET")){
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# EMET Block
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$output += " EMET Block`n"
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$obj.Message="EMET Block"
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if ($event.Message){
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# EMET Message is a blob of text that looks like this:
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#########################################################
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@ -151,37 +189,51 @@ function Main {
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# Module : mshtml.dll
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# Address : 0x6FBA7512, pull out relevant parts
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$array = $event.message -split '\n' # Split each line of the message into an array
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$message = $array[0]
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$text = $array[0]
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$application = Remove-Spaces($array[3])
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$command= $application -Replace "^Application: ",""
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$username = Remove-Spaces($array[4])
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$output += " - Message: $message`n"
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$output += " - $application`n"
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$output += " - $username`n"
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$obj.Message="EMET Block"
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$obj.Command = "$command"
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$obj.Results = "$text`n"
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$obj.Results += "$username`n"
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}
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Else{
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# If the message is blank: EMET is not installed locally.
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# This occurs when parsing remote event logs sent from systems with EMET installed
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$output += " Warning: EMET Message field is blank. Install EMET locally to see full details of this alert"
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$obj.Message="Warning: EMET Message field is blank. Install EMET locally to see full details of this alert"
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}
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Write-Output $obj
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}
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}
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ElseIf ($logname -eq "Applocker"){
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if ($event.id -eq 8004){
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if ($event.id -eq 8003){
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# ...was allowed to run but would have been prevented from running if the AppLocker policy were enforced.
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$obj.Message="Applocker Warning"
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$command = $event.message -Replace " was .*$",""
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$obj.Command=$command
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$obj.Results = $event.message
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Write-Output $obj
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}
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ElseIf ($event.id -eq 8004){
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$obj.Message="Applocker Block"
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# ...was prevented from running.
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$output += " Applocker block: " + $event.message
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$command = $event.message -Replace " was .*$",""
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$obj.Command=$command
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$obj.Results = $event.message
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Write-Output $obj
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}
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}
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ElseIf ($logname -eq "PowerShell"){
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#$event.pd
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if ($event.id -eq 4103){
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$pscommand= $eventXML.Event.EventData.Data[2]."#text"
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if ($pscommand -Match "Host Application"){
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$commandline= $eventXML.Event.EventData.Data[2]."#text"
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if ($commandline -Match "Host Application"){
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# Multiline replace, remove everything before "Host Application = "
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$pscommand = $pscommand -Replace "(?ms)^.*Host.Application = ",""
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$commandline = $commandline -Replace "(?ms)^.*Host.Application = ",""
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# Remove every line after the "Host Application = " line.
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$pscommand = $pscommand -Replace "(?ms)`n.*$",""
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if ($pscommand){
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$output += (Check-Command $pscommand $minlength $regexes $whitelist 0)
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$commandline = $commandline -Replace "(?ms)`n.*$",""
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if ($commandline){
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Check-Command
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}
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}
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}
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@ -214,9 +266,9 @@ function Main {
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#
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# This ignores scripts and grabs PowerShell CLIs
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if (-not ($eventxml.Event.EventData.Data[4]."#text")){
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$pscommand=$eventXML.Event.EventData.Data[2]."#text"
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if ($pscommand){
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$output += (Check-Command $pscommand 500 $regexes $whitelist 0)
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$commandline=$eventXML.Event.EventData.Data[2]."#text"
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if ($commandline){
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Check-Command
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}
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}
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}
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@ -224,32 +276,39 @@ function Main {
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ElseIf ($logname -eq "Sysmon"){
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# Check command lines
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if ($event.id -eq 1){
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$creator=$eventXML.Event.EventData.Data[14]."#text"
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$commandline=$eventXML.Event.EventData.Data[4]."#text"
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if ($commandline){
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$output += (Check-Command $commandline $minlength $regexes $whitelist 0)
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Check-Command
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}
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}
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# Check for unsigned EXEs/DLLs:
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ElseIf ($event.id -eq 7){
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if ($eventXML.Event.EventData.Data[6]."#text" -eq "false"){
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$image=$eventXML.Event.EventData.Data[3]."#text"
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$imageload=$eventXML.Event.EventData.Data[4]."#text"
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# $hash=$eventXML.Event.EventData.Data[5]."#text"
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$pscommand= " - Image: " + $image + "`r`n"
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$pscommand+= " - ImageLoaded: " + $imageload + "`r`n"
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$output+= " Unsigned image:`r`n"
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$output+= $pscommand
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# Check for unsigned EXEs/DLLs:
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# This can be very chatty, so it's disabled.
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# Set $checkunsigned to 1 (global variable section) to enable:
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if ($checkunsigned){
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if ($eventXML.Event.EventData.Data[6]."#text" -eq "false"){
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$obj.Message="Unsigned Image (DLL)"
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$image=$eventXML.Event.EventData.Data[3]."#text"
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$imageload=$eventXML.Event.EventData.Data[4]."#text"
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# $hash=$eventXML.Event.EventData.Data[5]."#text"
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$obj.Command=$imageload
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$obj.Results= "Loaded by: $image"
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Write-Output $obj
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}
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}
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}
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}
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if ($output){
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$event.TimeCreated
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$output
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""
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}
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}
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if ($failedlogons -gt $maxfailedlogons){
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"High number of failed logons in the security event log: " + $failedlogons
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# Iterate through failed logins hashtable (key is $username)
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foreach ($username in $failedlogins.Keys) {
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$count=$failedlogins.Get_Item($username)
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if ($count -gt $maxfailedlogons){
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$obj.Message="High number of failed logons"
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$obj.Results= "Username: $username`n"
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$obj.Results += "$count failed logons"
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Write-Output $obj
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}
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}
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}
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@ -298,7 +357,7 @@ function Check-Options($file, $log)
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"Security" {$logname="Security"}
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"System" {$logname="System"}
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"Application" {$logname="Application"}
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"Microsoft-Windows-AppLocker*" {$logname="Applocker"}
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"Microsoft-Windows-AppLocker/EXE and DLL" {$logname="Applocker"}
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"Microsoft-Windows-PowerShell/Operational" {$logname="Powershell"}
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"Microsoft-Windows-Sysmon/Operational" {$logname="Sysmon"}
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default {"Logic error 3, should not reach here...";Exit 1}
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@ -338,7 +397,7 @@ function Create-Filter($file, $logname)
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"Security" {$filter="@{Logname=""Security"";ID=$sec_events}"}
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"System" {$filter="@{Logname=""System"";ID=$sys_events}"}
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"Application" {$filter="@{Logname=""Application"";ID=$app_events}"}
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"Applocker" {$filter="@{logname=""Microsoft-Windows-AppLocker"";ID=$applocker_events}"}
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"Applocker" {$filter="@{logname=""Microsoft-Windows-AppLocker/EXE and DLL"";ID=$applocker_events}"}
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"Powershell" {$filter="@{logname=""Microsoft-Windows-PowerShell/Operational"";ID=$powershell_events}"}
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"Sysmon" {$filter="@{logname=""Microsoft-Windows-Sysmon/Operational"";ID=$sysmon_events}"}
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default {"Logic error 2, should not reach here...";Exit 1}
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@ -348,7 +407,7 @@ function Create-Filter($file, $logname)
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}
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function Check-Command($commandline,$minlength,$regexes,$whitelist,$servicecmd){
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function Check-Command(){
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$text=""
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$base64=""
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# Check to see if command is whitelisted
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@ -358,13 +417,12 @@ function Check-Command($commandline,$minlength,$regexes,$whitelist,$servicecmd){
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return
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}
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}
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#$cmdlength=$commandline.length
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#if ($cmdlength -gt $minlength){
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if ($commandline.length -gt $minlength){
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$text += " - Long Command Line: greater than $minlength bytes`n"
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$text += "Long Command Line: greater than $minlength bytes`n"
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}
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$text += (Check-Obfu $commandline)
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$text += (Check-Regex $commandline $regexes 0)
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$text += (Check-Regex $commandline 0)
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$text += (Check-Creator $commandline $creator)
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# Check for base64 encoded function, decode and print if found
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# This section is highly use case specific, other methods of base64 encoding and/or compressing may evade these checks
|
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if ($commandline -Match "\-enc.*[A-Za-z0-9/+=]{100}"){
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@ -379,41 +437,38 @@ function Check-Command($commandline,$minlength,$regexes,$whitelist,$servicecmd){
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# Metasploit-style compressed and base64-encoded function. Uncompress it.
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$decoded=New-Object IO.MemoryStream(,[Convert]::FromBase64String($base64))
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$uncompressed=(New-Object IO.StreamReader(((New-Object IO.Compression.GzipStream($decoded,[IO.Compression.CompressionMode]::Decompress))),[Text.Encoding]::ASCII)).ReadToEnd()
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$text += " Decoded/decompressed Base64:" + $uncompressed
|
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$text += " - Base64-encoded and compressed function`n"
|
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$obj.Decoded=$uncompressed
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$text += "Base64-encoded and compressed function`n"
|
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}
|
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else{
|
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$decoded = [System.Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String($base64))
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$text += " Decoded Base64:" + $decoded + "`n"
|
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$text += " - Base64-encoded function`n"
|
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$obj.Decoded=$decoded
|
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$text += "Base64-encoded function`n"
|
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$text += (Check-Obfu $decoded)
|
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$text += (Check-Regex $decoded $regexes 0)
|
||||
#foreach ($regex in $regexes){
|
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# if ($regex.Type -eq 0) { # Image Path match
|
||||
# if ($decoded -Match $regex.regex) {
|
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# $text += " - " + $regex.String + "`n"
|
||||
# }
|
||||
# }
|
||||
#}
|
||||
$text += (Check-Regex $decoded 0)
|
||||
}
|
||||
}
|
||||
if ($text){
|
||||
if ($servicecmd){
|
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return " Service File Name: $commandline`n" + $text
|
||||
$obj.Message = "Suspicious Service Command"
|
||||
$obj.Results = "Service name: $servicename`n"
|
||||
}
|
||||
Else{
|
||||
return " Command Line: $commandline`n" + $text
|
||||
$obj.Message = "Suspicious Command Line"
|
||||
}
|
||||
$obj.Command = $commandline
|
||||
$obj.Results += $text
|
||||
Write-Output $obj
|
||||
}
|
||||
return ""
|
||||
return
|
||||
}
|
||||
|
||||
function Check-Regex($string,$regexes,$type){
|
||||
function Check-Regex($string,$type){
|
||||
$regextext="" # Local variable for return output
|
||||
foreach ($regex in $regexes){
|
||||
if ($regex.Type -eq $type) { # Type is 0 for Commands, 1 for services. Set in regexes.csv
|
||||
if ($string -Match $regex.regex) {
|
||||
$regextext += " - " + $regex.String + "`n"
|
||||
$regextext += $regex.String + "`n"
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -422,11 +477,8 @@ function Check-Regex($string,$regexes,$type){
|
||||
|
||||
function Check-Obfu($string){
|
||||
# Check for special characters in the command. Inspired by Invoke-Obfuscation: https://twitter.com/danielhbohannon/status/778268820242825216
|
||||
# There are many ways to do this, including regex. Need a way that doesn't kill the CPU.
|
||||
#
|
||||
$obfutext="" # Local variable for return output
|
||||
$minpercent=.65 # minimum percentage of alphanumeric and common symbols
|
||||
$maxbinary=.50 # Maximum percentage of zeros and ones
|
||||
$lowercasestring=$string.ToLower()
|
||||
$length=$lowercasestring.length
|
||||
$noalphastring = $lowercasestring -replace "[a-z0-9/\;:|.]"
|
||||
@ -434,23 +486,41 @@ function Check-Obfu($string){
|
||||
# Calculate the percent alphanumeric/common symbols
|
||||
if ($length -gt 0){
|
||||
$percent=(($length-$noalphastring.length)/$length)
|
||||
# Adjust minpercent for very short commands, to avoid triggering short warnings
|
||||
if (($length/100) -lt $minpercent){
|
||||
$minpercent=$minpercent-($minpercent)+($length/100)
|
||||
}
|
||||
if ($percent -lt $minpercent){
|
||||
$percent = "{0:P0}" -f $percent # Convert to a percent
|
||||
$obfutext += " - Possible command obfuscation: only $percent alphanumeric and common symbols`n"
|
||||
$obfutext += "Possible command obfuscation: only $percent alphanumeric and common symbols`n"
|
||||
}
|
||||
# Calculate the percent of binary characters
|
||||
#$percent=(($length-$nobinarystring.length/$length)/$length)
|
||||
$percent=(($nobinarystring.length-$length/$length)/$length)
|
||||
$binarypercent = 1-$percent
|
||||
if ($binarypercent -gt $maxbinary){
|
||||
#$binarypercent = 1-$percent
|
||||
$binarypercent = "{0:P0}" -f $binarypercent # Convert to a percent
|
||||
$obfutext += " - Possible command obfuscation: $binarypercent zeroes and ones (possible numeric or binary encoding)`n"
|
||||
$obfutext += "Possible command obfuscation: $binarypercent zeroes and ones (possible numeric or binary encoding)`n"
|
||||
}
|
||||
}
|
||||
return $obfutext
|
||||
}
|
||||
|
||||
function Check-Creator($command,$creator){
|
||||
$creatortext="" # Local variable for return output
|
||||
if ($creator){
|
||||
if ($command -Match "powershell"){
|
||||
if ($creator -Match "PSEXESVC"){
|
||||
$creatortext += "PowerShell launched via PsExec: $creator`n"
|
||||
}
|
||||
ElseIf($creator -Match "WmiPrvSE"){
|
||||
$creatortext += "PowerShell launched via WMI: $creator`n"
|
||||
}
|
||||
}
|
||||
}
|
||||
return $creatortext
|
||||
}
|
||||
|
||||
function Remove-Spaces($string){
|
||||
# Changes this: Application : C:\Program Files (x86)\Internet Explorer\iexplore.exe
|
||||
# to this: Application: C:\Program Files (x86)\Internet Explorer\iexplore.exe
|
||||
|
||||
Reference in New Issue
Block a user