I have an ASP.NET application that accesses private key in a certificate in the certificates store. On Windows Server 2003 I was able to use winhttpcertcfg.exe to give private key access to the NETWORK SERVICE account. How do I give permissions to access a Private Key in a certificate in the certificate store (Local Computer\Personal) on a Windows Server 2008 R2 in an IIS 7.5 website?
I've tried giving Full Trust access to "Everyone", "IIS AppPool\DefaultAppPool", "IIS_IUSRS", and everyother security account I could find using the Certificates MMC (Server 2008 R2). However the below code demonstrates that the code does not have access to the Private Key of a certificate that was imported with the private key. The code instead throws and error everytime the private key property is accessed.
Default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<%@ Import Namespace="System.Security.Cryptography.X509Certificates" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Repeater ID="repeater1" runat="server">
<HeaderTemplate>
<table>
<tr>
<td>
Cert
</td>
<td>
Public Key
</td>
<td>
Private Key
</td>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<%#((X509Certificate2)Container.DataItem).GetNameInfo(X509NameType.SimpleName, false) %>
</td>
<td>
<%#((X509Certificate2)Container.DataItem).HasPublicKeyAccess() %>
</td>
<td>
<%#((X509Certificate2)Container.DataItem).HasPrivateKeyAccess() %>
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table></FooterTemplate>
</asp:Repeater>
</div>
</form>
</body>
</html>
Default.aspx.cs
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Web.UI;
public partial class _Default : Page
{
public X509Certificate2Collection Certificates;
protected void Page_Load(object sender, EventArgs e)
{
// Local Computer\Personal
var store = new X509Store(StoreLocation.LocalMachine);
// create and open store for read-only access
store.Open(OpenFlags.ReadOnly);
Certificates = store.Certificates;
repeater1.DataSource = Certificates;
repeater1.DataBind();
}
}
public static class Extensions
{
public static string HasPublicKeyAccess(this X509Certificate2 cert)
{
try
{
AsymmetricAlgorithm algorithm = cert.PublicKey.Key;
}
catch (Exception ex)
{
return "No";
}
return "Yes";
}
public static string HasPrivateKeyAccess(this X509Certificate2 cert)
{
try
{
string algorithm = cert.PrivateKey.KeyExchangeAlgorithm;
}
catch (Exception ex)
{
return "No";
}
return "Yes";
}
}
This question is related to
asp.net
certificate
iis-7.5
winhttp
The answer is
For me, it was nothing more than re-importing the certificate with "Allow private key to be exported" checked.
I guess it is necessary, but it does make me nervous as it is a third party app accessing this certificate.
Although I have attended the above, I have come to this point after many attempts. 1- If you want access to the certificate from the store, you can do this as an example 2- It is much easier and cleaner to produce the certificate and use it via a path
Asp.net Core 2.2 OR1:
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Pkcs;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Operators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Crypto.Prng;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Pkcs;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.X509;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading.Tasks;
namespace Tursys.Pool.Storage.Api.Utility
{
class CertificateManager
{
public static X509Certificate2 GetCertificate(string caller)
{
AsymmetricKeyParameter caPrivateKey = null;
X509Certificate2 clientCert;
X509Certificate2 serverCert;
clientCert = GetCertificateIfExist("CN=127.0.0.1", StoreName.My, StoreLocation.LocalMachine);
serverCert = GetCertificateIfExist("CN=MyROOTCA", StoreName.Root, StoreLocation.LocalMachine);
if (clientCert == null || serverCert == null)
{
var caCert = GenerateCACertificate("CN=MyROOTCA", ref caPrivateKey);
addCertToStore(caCert, StoreName.Root, StoreLocation.LocalMachine);
clientCert = GenerateSelfSignedCertificate("CN=127.0.0.1", "CN=MyROOTCA", caPrivateKey);
var p12 = clientCert.Export(X509ContentType.Pfx);
addCertToStore(new X509Certificate2(p12, (string)null, X509KeyStorageFlags.Exportable | X509KeyStorageFlags.PersistKeySet), StoreName.My, StoreLocation.LocalMachine);
}
if (caller == "client")
return clientCert;
return serverCert;
}
public static X509Certificate2 GenerateSelfSignedCertificate(string subjectName, string issuerName, AsymmetricKeyParameter issuerPrivKey)
{
const int keyStrength = 2048;
// Generating Random Numbers
CryptoApiRandomGenerator randomGenerator = new CryptoApiRandomGenerator();
SecureRandom random = new SecureRandom(randomGenerator);
// The Certificate Generator
X509V3CertificateGenerator certificateGenerator = new X509V3CertificateGenerator();
// Serial Number
BigInteger serialNumber = BigIntegers.CreateRandomInRange(BigInteger.One, BigInteger.ValueOf(Int64.MaxValue), random);
certificateGenerator.SetSerialNumber(serialNumber);
// Signature Algorithm
//const string signatureAlgorithm = "SHA256WithRSA";
//certificateGenerator.SetSignatureAlgorithm(signatureAlgorithm);
// Issuer and Subject Name
X509Name subjectDN = new X509Name(subjectName);
X509Name issuerDN = new X509Name(issuerName);
certificateGenerator.SetIssuerDN(issuerDN);
certificateGenerator.SetSubjectDN(subjectDN);
// Valid For
DateTime notBefore = DateTime.UtcNow.Date;
DateTime notAfter = notBefore.AddYears(2);
certificateGenerator.SetNotBefore(notBefore);
certificateGenerator.SetNotAfter(notAfter);
// Subject Public Key
AsymmetricCipherKeyPair subjectKeyPair;
var keyGenerationParameters = new KeyGenerationParameters(random, keyStrength);
var keyPairGenerator = new RsaKeyPairGenerator();
keyPairGenerator.Init(keyGenerationParameters);
subjectKeyPair = keyPairGenerator.GenerateKeyPair();
certificateGenerator.SetPublicKey(subjectKeyPair.Public);
// Generating the Certificate
AsymmetricCipherKeyPair issuerKeyPair = subjectKeyPair;
ISignatureFactory signatureFactory = new Asn1SignatureFactory("SHA512WITHRSA", issuerKeyPair.Private, random);
// selfsign certificate
Org.BouncyCastle.X509.X509Certificate certificate = certificateGenerator.Generate(signatureFactory);
// correcponding private key
PrivateKeyInfo info = PrivateKeyInfoFactory.CreatePrivateKeyInfo(subjectKeyPair.Private);
// merge into X509Certificate2
X509Certificate2 x509 = new System.Security.Cryptography.X509Certificates.X509Certificate2(certificate.GetEncoded());
Asn1Sequence seq = (Asn1Sequence)Asn1Object.FromByteArray(info.PrivateKeyAlgorithm.GetDerEncoded());
if (seq.Count != 9)
{
//throw new PemException("malformed sequence in RSA private key");
}
RsaPrivateKeyStructure rsa = RsaPrivateKeyStructure.GetInstance(info.ParsePrivateKey());
RsaPrivateCrtKeyParameters rsaparams = new RsaPrivateCrtKeyParameters(
rsa.Modulus, rsa.PublicExponent, rsa.PrivateExponent, rsa.Prime1, rsa.Prime2, rsa.Exponent1, rsa.Exponent2, rsa.Coefficient);
try
{
var rsap = DotNetUtilities.ToRSA(rsaparams);
x509 = x509.CopyWithPrivateKey(rsap);
//x509.PrivateKey = ToDotNetKey(rsaparams);
}
catch(Exception ex)
{
;
}
//x509.PrivateKey = DotNetUtilities.ToRSA(rsaparams);
return x509;
}
public static AsymmetricAlgorithm ToDotNetKey(RsaPrivateCrtKeyParameters privateKey)
{
var cspParams = new CspParameters
{
KeyContainerName = Guid.NewGuid().ToString(),
KeyNumber = (int)KeyNumber.Exchange,
Flags = CspProviderFlags.UseMachineKeyStore
};
var rsaProvider = new RSACryptoServiceProvider(cspParams);
var parameters = new RSAParameters
{
Modulus = privateKey.Modulus.ToByteArrayUnsigned(),
P = privateKey.P.ToByteArrayUnsigned(),
Q = privateKey.Q.ToByteArrayUnsigned(),
DP = privateKey.DP.ToByteArrayUnsigned(),
DQ = privateKey.DQ.ToByteArrayUnsigned(),
InverseQ = privateKey.QInv.ToByteArrayUnsigned(),
D = privateKey.Exponent.ToByteArrayUnsigned(),
Exponent = privateKey.PublicExponent.ToByteArrayUnsigned()
};
rsaProvider.ImportParameters(parameters);
return rsaProvider;
}
public static X509Certificate2 GenerateCACertificate(string subjectName, ref AsymmetricKeyParameter CaPrivateKey)
{
const int keyStrength = 2048;
// Generating Random Numbers
CryptoApiRandomGenerator randomGenerator = new CryptoApiRandomGenerator();
SecureRandom random = new SecureRandom(randomGenerator);
// The Certificate Generator
X509V3CertificateGenerator certificateGenerator = new X509V3CertificateGenerator();
// Serial Number
BigInteger serialNumber = BigIntegers.CreateRandomInRange(BigInteger.One, BigInteger.ValueOf(Int64.MaxValue), random);
certificateGenerator.SetSerialNumber(serialNumber);
// Signature Algorithm
//const string signatureAlgorithm = "SHA256WithRSA";
//certificateGenerator.SetSignatureAlgorithm(signatureAlgorithm);
// Issuer and Subject Name
X509Name subjectDN = new X509Name(subjectName);
X509Name issuerDN = subjectDN;
certificateGenerator.SetIssuerDN(issuerDN);
certificateGenerator.SetSubjectDN(subjectDN);
// Valid For
DateTime notBefore = DateTime.UtcNow.Date;
DateTime notAfter = notBefore.AddYears(2);
certificateGenerator.SetNotBefore(notBefore);
certificateGenerator.SetNotAfter(notAfter);
// Subject Public Key
AsymmetricCipherKeyPair subjectKeyPair;
KeyGenerationParameters keyGenerationParameters = new KeyGenerationParameters(random, keyStrength);
RsaKeyPairGenerator keyPairGenerator = new RsaKeyPairGenerator();
keyPairGenerator.Init(keyGenerationParameters);
subjectKeyPair = keyPairGenerator.GenerateKeyPair();
certificateGenerator.SetPublicKey(subjectKeyPair.Public);
// Generating the Certificate
AsymmetricCipherKeyPair issuerKeyPair = subjectKeyPair;
// selfsign certificate
//Org.BouncyCastle.X509.X509Certificate certificate = certificateGenerator.Generate(issuerKeyPair.Private, random);
ISignatureFactory signatureFactory = new Asn1SignatureFactory("SHA512WITHRSA", issuerKeyPair.Private, random);
// selfsign certificate
Org.BouncyCastle.X509.X509Certificate certificate = certificateGenerator.Generate(signatureFactory);
X509Certificate2 x509 = new System.Security.Cryptography.X509Certificates.X509Certificate2(certificate.GetEncoded());
CaPrivateKey = issuerKeyPair.Private;
return x509;
//return issuerKeyPair.Private;
}
public static bool addCertToStore(System.Security.Cryptography.X509Certificates.X509Certificate2 cert, System.Security.Cryptography.X509Certificates.StoreName st, System.Security.Cryptography.X509Certificates.StoreLocation sl)
{
bool bRet = false;
try
{
X509Store store = new X509Store(st, sl);
store.Open(OpenFlags.ReadWrite);
store.Add(cert);
store.Close();
}
catch
{
}
return bRet;
}
protected internal static X509Certificate2 GetCertificateIfExist(string subjectName, StoreName store, StoreLocation location)
{
using (var certStore = new X509Store(store, location))
{
certStore.Open(OpenFlags.ReadOnly);
var certCollection = certStore.Certificates.Find(
X509FindType.FindBySubjectDistinguishedName, subjectName, false);
X509Certificate2 certificate = null;
if (certCollection.Count > 0)
{
certificate = certCollection[0];
}
return certificate;
}
}
}
}
OR 2:
services.AddDataProtection()
//.PersistKeysToFileSystem(new DirectoryInfo(@"c:\temp-keys"))
.ProtectKeysWithCertificate(
new X509Certificate2(Path.Combine(Directory.GetCurrentDirectory(), "clientCert.pfx"), "Password")
)
.UnprotectKeysWithAnyCertificate(
new X509Certificate2(Path.Combine(Directory.GetCurrentDirectory(), "clientCert.pfx"), "Password")
);
In Certificates Panel, right click some certificate -> All tasks -> Manage private key -> Add IIS_IUSRS User with full control
In my case, I didnt't need to install my certificate with "Allow private key to be exported" option checked, like said in other answers.
I figured out how to do this in Powershell that someone asked about:
$keyname=(((gci cert:\LocalMachine\my | ? {$_.thumbprint -like $thumbprint}).PrivateKey).CspKeyContainerInfo).UniqueKeyContainerName
$keypath = $env:ProgramData + “\Microsoft\Crypto\RSA\MachineKeys\”
$fullpath=$keypath+$keyname
$Acl = Get-Acl $fullpath
$Ar = New-Object System.Security.AccessControl.FileSystemAccessRule("IIS AppPool\$iisAppPoolName", "Read", "Allow")
$Acl.SetAccessRule($Ar)
Set-Acl $fullpath $Acl
If you are trying to load a cert from a .pfx file in IIS the solution may be as simple as enabling this option for the Application Pool.
Right click on the App Pool and select Advanced Settings.
Then enable Load User Profile
Note on granting permissions via MMC, Certs, Select Cert, right-click, all-tasks, "Manage Private Keys"
Manage Private Keys is only on the menu list for Personal... So if you've put your cert in Trusted People, etc. you're out of luck.
We found a way around this which worked for us. Drag and drop the cert to Personal, do the Manage Private Keys thing to grant permissions. Remember to set to use object-type built-ins and use the local machine not domain. We granted rights to the DefaultAppPool user and left it at that.
Once you're done, drag and drop the cert back where ever you originally had it. Presto.
Complementing the answers this is a guide to find the private key of the certificate and add the permissions.
This is the guide to get FindPrivateKey.exe found in the guide for find the private key of the certificate.
Source: Stackoverflow.com