CVE-2013-3900 PoC — WinVerifyTrust Signature Validation Vulnerability

Title:WinVerifyTrust Signature Validation Vulnerability (CVE-2013-3900)
Description:Why is Microsoft republishing a CVE from 2013? We are republishing CVE-2013-3900 in the Security Update Guide to update the Security Updates table and to inform customers that the EnableCertPaddingCheck is available in all currently supported versions of Windows 10 and Windows 11. While the format is different from the original CVE published in 2013, except for clarifications about how to configure the EnableCertPaddingCheck registry value, the information herein remains unchanged from the original text published on December 10, 2013, Microsoft does not plan to enforce the stricter verification behavior as a default functionality on supported releases of Microsoft Windows. This behavior remains available as an opt-in feature via reg key setting, and is available on supported editions of Windows released since December 10, 2013. This includes all currently supported versions of Windows 10 and Windows 11. The supporting code for this reg key was incorporated at the time of release for Windows 10 and Windows 11, so no security update is required; however, the reg key must be set. See the Security Updates table for the list of affected software. Vulnerability Description A remote code execution vulnerability exists in the way that the WinVerifyTrust function handles Windows Authenticode signature verification for portable executable (PE) files. An anonymous attacker could exploit the vulnerability by modifying an existing signed executable file to leverage unverified portions of the file in such a way as to add malicious code to the file without invalidating the signature. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Exploitation of this vulnerability requires that a user or application run or install a specially crafted, signed PE file. An attacker could modify an... See more at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2013-3900

```powershell
# CVE-2013-3900 Remediation Script

# Define registry paths for both 32-bit and 64-bit configurations
$regPaths = @(
    "HKLM:\Software\Microsoft\Cryptography\Wintrust\Config",
    "HKLM:\Software\Wow6432Node\Microsoft\Cryptography\Wintrust\Config"
)

# Function to add or update the registry key
function Set-EnableCertPaddingCheck {
    param (
        [string]$path
    )
    if (!(Test-Path $path)) {
        New-Item -Path $path -Force | Out-Null
    }
    Set-ItemProperty -Path $path -Name "EnableCertPaddingCheck" -Value 1 -Type DWord
}

# Apply the fix to both registry paths
foreach ($path in $regPaths) {
    Set-EnableCertPaddingCheck -path $path
}

# Confirm changes
Write-Host "Registry keys updated successfully!" -ForegroundColor Green

# Verify the changes
foreach ($path in $regPaths) {
    $value = Get-ItemProperty -Path $path | Select-Object -ExpandProperty EnableCertPaddingCheck -ErrorAction SilentlyContinue
    if ($value -eq 1) {
        Write-Host "Verification successful for $path: EnableCertPaddingCheck = 1" -ForegroundColor Green
    } else {
        Write-Host "Verification failed for $path!" -ForegroundColor Red
    }
}

# Restart the system to apply changes
Write-Host "Restarting system in 10 seconds to apply changes..." -ForegroundColor Yellow
Start-Sleep -Seconds 10
Restart-Computer -Force
```

 [4.0K]  /data/pocs/a5c265f74ab5d635419998a3bb0744f130374cac
└── [1.3K]  README.md

0 directories, 1 file