#CVE-2013-3900 is a remote code execution vulnerability in the way Microsoft's WinVerifyTrust function handles Windows Authenticode signature verification. This flaw allows an attacker to modify a signed executable file by adding malicious code to an unverified portion #of the file without invalidating its signature.

#The mitigation for this vulnerability is an opt-in feature that requires a specific registry setting. Once enabled, Windows will perform a stricter verification of Authenticode signatures, ensuring that no extraneous data is present in the signed file.

-WinVerifyTrust-Signature-Validation-CVE-2013-3900-Mitigation

Define the registry key paths

$regPath32 = "HKLM:\Software\Microsoft\Cryptography\Wintrust\Config" $regPath64 = "HKLM:\Software\Wow6432Node\Microsoft\Cryptography\Wintrust\Config" $valueName = "EnableCertPaddingCheck" $valueData = 1

Check and create the registry key for 64-bit systems

if (-not (Test-Path $regPath64)) { New-Item -Path $regPath64 -Force | Out-Null Write-Host "Created registry path: $regPath64" }

Set the registry value for 64-bit systems

Set-ItemProperty -Path $regPath64 -Name $valueName -Value $valueData -Type DWord -Force | Out-Null Write-Host "Set $valueName to $valueData in $regPath64"

Check and create the registry key for 32-bit systems

if (-not (Test-Path $regPath32)) { New-Item -Path $regPath32 -Force | Out-Null Write-Host "Created registry path: $regPath32" }

Set the registry value for 32-bit systems

Set-ItemProperty -Path $regPath32 -Name $valueName -Value $valueData -Type DWord -Force | Out-Null Write-Host "Set $valueName to $valueData in $regPath32"

Write-Host "`nMitigation script complete."