Hack Attacks Revealed A Complete Reference with Custom Security Hacking Toolkit phần 3 pdf

153 Figure 6.3 IP address example. Binary When decimal numbers are entered into the computer, the system converts these into binary format, 0s and 1s, which basically correlate to electrical charges—charged versus uncharged. IP addresses, for example, are subnetted and calculated with binary notation. An example of an IP address with 24 bits in the mask is shown in Figure 6.3. The first octet (206) indicates a Class C (Internet-assigned) IP address range with the format network.network.network.host, with a standard mask binary indicating 255.255.255.0. This means that we have 8 bits in the last octet for hosts. The 8 bits that make up the last, or fourth, octet are understood by infrastructure equipment such as routers and software in the following manner: Bit: 1 2 3 4 5 6 7 8 Value: 128 64 32 16 8 4 2 1 = 255 (254 usable hosts) In this example of a full Class C, we only have 254 usable IP addresses for hosts; 0 and 255 cannot be used as host addresses since the network number is 0 and the broadcast address is 255. Note that when a bit is used, we indicate it with a 1: 3 Bits: 1 1 1 Value: 128 64 32 16 8 4 2 1 When a bit is not used, we indicate this with a 0: 3 Bits: 0 0 0 0 0 Value: 128 64 32 16 8 4 2 1 As a result: 3 Bits: 1 1 1 0 0 0 0 0 Value: 128 64 32 16 8 4 2 1 We add the decimal value of the used bits: 128 + 64 + 32 = 224. This means that the binary value 11100000 equates to the decimal value 224. DECIMAL BINARY 224 11100000 154 Hex The hexadecimal system is a form of binary shorthand. Internetworking equipment such as routers use this format while formulating headers to easily indicate Token Ring numbers, bridge numbers, networks, and so on, to reduce header sizes and transmission congestion. Typically, hex is derived from the binary format, which is derived from decimal. Hex was designed so that the 8 bits in the binary 11100000 (Decimal=224) will equate to only two hex characters, each representing 4 bits. To clarify, take a look at the binary value for 224 again: • 1110000 In hex, we break this 8-bit number into 4-bit pairs: • 11100000 Each bit in the 4-bit pairs has a decimal value, starting from left to right: 8 then 4 then 2 then 1 for the last bit: 8 4 2 1 8 4 2 1 1 1 1 0 0 0 0 0 Now we add the bits that are ‘‘on,” or that have a 1 in each of the 4-bit pairs: 8 4 2 1 = 8 + 4 + 2 + 0 = 14 8 4 2 1 = 0 + 0 + 0 + 0 = 0 1 1 1 0 0 0 0 0 In this example, the decimal values that represent the hex characters in each of the 4-bit pairs are 14 and 0. To convert these to actual hex, use Table 6.2. Using this chart, the hex conversion for the decimals 14 and 0 (14 for the first 4-bit pair and 0 for the second 4-bit pair) = e0. Let’s look at one more example: We’ll convert the decimal number 185 to binary: Bits: 1 0 1 1 1 0 0 1 Value: 128 64 32 16 8 4 2 1 = 185 Binary for 185: 10111001 (bits indicated above) Table 6.2 Decimal-to-Hex Conversion Table DECIMAL HEX DECIMAL HEX 0 0 8 8 1 1 9 9 2 2 10 a 3 3 11 b 4 4 12 c 155 5 5 13 d 6 6 14 e 7 7 15 f Then we’ll convert the binary number 10111001 indicated , to hex, which we break into 4-bit pairs: • 1011 1001 Each bit in the 4-bit pairs has a decimal value, starting from left to right: 8 then 4 then 2 then 1 for the last bit: • 8 4 2 18 4 2 1 • 1 0 1 11 0 0 1 Now we add the bits that have a 1 in each of the 4-bit pairs: 8 4 2 1 = 8 + 0 + 2 + 1 = 11 8 4 2 1 = 8 + 0 + 0 + 1 = 9 1 0 1 1 1 0 0 1 Using the hex chart, the hex conversion for the decimals 11 and 9 (11 for the first 4-bit pair and 9 for the second 4-bit pair) = b9, as shown here: DECIMAL BINARY HEX 185 10111001 b9 224 11100000 e0 For quick reference, refer to Table 6.3 for decimal, binary, and hex conversions. Table 6.3 Decimal, Binary, Hex Conversion Table DECIMAL BINARY HEX 0 0000 0 1 0001 1 2 0010 2 3 0011 3 4 0100 4 5 0101 5 6 0110 6 7 0111 7 8 1000 8 156 9 1001 9 10 1010 a 11 1011 b 12 1100 c 13 1101 d 14 1110 e 15 1111 f 16 0001 0000 10 17 0001 0001 11 18 0001 0010 12 19 0001 0011 13 20 0001 0100 14 21 0001 0101 15 22 0001 0110 16 23 0001 0111 17 24 0001 1000 18 25 0001 1001 19 26 0001 1010 1a 27 0001 1011 1b 28 0001 1100 1c 29 0001 1101 1d 30 0001 1110 1e 31 0001 1111 1f 32 0010 0000 20 33 0010 0001 21 34 0010 0010 22 35 0010 0011 23 36 0010 0100 24 157 37 0010 0101 25 38 0010 0110 26 39 0010 0111 27 40 0010 1000 28 41 0010 1001 29 42 0010 1010 2a 43 0010 1011 2b 44 0010 1100 2c 45 0010 1101 2d 46 0010 1110 2e 47 0010 1111 2f 48 0011 0000 30 49 0011 0001 31 50 0011 0010 32 51 0011 0011 33 52 0011 0100 34 53 0011 0101 35 54 0011 0110 36 55 0011 0111 37 56 0011 1000 38 57 0011 1001 39 58 0011 1010 3a 59 0011 1011 3b 60 0011 1100 3c 61 0011 1101 3d 62 0011 1110 3e 63 0011 1111 3f 64 0100 0000 40 158 65 0100 0001 41 66 0100 0010 42 67 0100 0011 43 68 0100 0100 44 69 0100 0101 45 70 0100 0110 46 71 0100 0111 47 72 0100 1000 48 73 0100 1001 49 74 0100 1010 4a 75 0100 1011 4b 76 0100 1100 4c 77 0100 1101 4d 78 0100 1110 4e 79 0100 1111 4f 80 0101 0000 50 81 0101 0001 51 82 0101 0010 52 83 0101 0011 53 84 0101 0100 54 85 0101 0101 55 86 0101 0110 56 87 0101 0111 57 88 0101 1000 58 89 0101 1001 59 90 0101 1010 5a 91 0101 1011 5b 92 0101 1100 5c 159 93 0101 1101 5d 94 0101 1110 5e 95 0101 1111 5f 96 0110 0000 60 97 0110 0001 61 98 0110 0010 62 99 0110 0011 63 100 0110 0100 64 101 0110 0101 65 102 0110 0110 66 103 0110 0111 67 104 0110 1000 68 105 0110 1001 69 106 0110 1010 6a 107 0110 1011 6b 108 0110 1100 6c 109 0110 1101 6d 110 0110 1110 6e 111 0110 1111 6f 112 0111 0000 70 113 0111 0001 71 114 0111 0010 72 115 0111 0011 73 116 0111 0100 74 117 0111 0101 75 118 0111 0110 76 119 0111 0111 77 120 0111 1000 78 160 121 0111 1001 79 122 0111 1010 7a 123 0111 1011 7b 124 0111 1100 7c 125 0111 1101 7d 126 0111 1110 7e 127 0111 1111 7f 128 1000 0000 80 129 1000 0001 81 130 1000 0010 82 131 1000 0011 83 132 1000 0100 84 133 1000 0101 85 134 1000 0110 86 135 1000 0111 87 136 1000 1000 88 137 1000 1001 89 138 1000 1010 8a 139 1000 1011 8b 140 1000 1100 8c 141 1000 1101 8d 142 1000 1110 8e 143 1000 1111 8f 144 1001 0000 90 145 1001 0001 91 146 1001 0010 92 147 1001 0011 93 148 1001 0100 94 161 149 1001 0101 95 150 1001 0110 96 151 1001 0111 97 152 1001 1000 98 153 1001 1001 99 154 1001 1010 9a 155 1001 1011 9b 156 1001 1100 9c 157 1001 1101 9d 158 1001 1110 9e 159 1001 1111 9f 160 1010 0000 a0 161 1010 0001 a1 162 1010 0010 a2 163 1010 0011 a3 164 1010 0100 a4 165 1010 0101 a5 166 1010 0110 a6 167 1010 0111 a7 168 1010 1000 a8 169 1010 1001 a9 170 1010 1010 aa 171 1010 1011 ab 172 1010 1100 ac 173 1010 1101 ad 174 1010 1110 ae 175 1010 1111 af 176 1011 0000 b0 162 177 1011 0001 b1 178 1011 0010 b2 179 1011 0011 b3 180 1011 0100 b4 181 1011 0101 b5 182 1011 0110 b6 183 1011 0111 b7 184 1011 1000 b8 185 1011 1001 b9 186 1011 1010 ba 187 1011 1011 bb 188 1011 1100 bc 189 1011 1101 bd 190 1011 1110 be 191 1011 1111 bf 192 1100 0000 c0 193 1100 0001 c1 194 1100 0010 c2 195 1100 0011 c3 196 1100 0100 c4 197 1100 0101 c5 198 1100 0110 c6 199 1100 0111 c7 200 1100 1000 c8 201 1100 1001 c9 202 1100 1010 ca 203 1100 1011 cb 204 1100 1100 cc [...]... Integrated Solutions TRFS 32 992 80E0–80E3 – – Allen–Bradley 32 996 80E4–80F0 – – Datability 33 010 80F2 – – Retix 33 011 80F3 – – AppleTalk AARP (Kinetics) 33 012 80F4–80F5 – – Kinetics 33 015 80F7 – – Apollo Computer 33 0 23 80FF–81 03 – – Wellfleet Communications 33 031 8107–8109 – – Symbolics Private 33 072 8 130 – – Hayes Microcomputers 33 0 73 8 131 – – VG Laboratory Systems 33 074 8 132 –8 136 – – Bridge Communications... 80 7A – – Matra 32 891 807B – – Dansk Data Elektronik 32 892 807C – – Merit Internodal 32 8 93 807D–807F – – Vitalink Communications 32 896 8080 – – Vitalink TransLAN III 32 897 8081–80 83 – – Counterpoint Computers 32 9 23 809B – – Appletalk 32 924 809C–809E – – Datability 32 927 809F – – Spider Systems Ltd 32 931 8 0A3 – – Nixdorf Computers 32 932 8 0A4 –80B3 – – Siemens Gammasonics Inc 32 960 80C0–80C3 – – DCA Data... 32 822 8 036 – – Aeonic Systems 32 824 8 038 – – DEC LANBridge 32 825 8 039 –803C – – DEC Unassigned 32 829 803D – – DEC Ethernet Encryption 32 830 803E – – DEC Unassigned 32 831 803F – – DEC LAN Traffic Monitor 32 832 8040–8042 – – DEC Unassigned 32 836 8044 – – Planning Research Corp 32 838 8046 – – AT&T 32 839 8047 – – AT&T 32 841 8049 – – ExperData 32 859 805B – – Stanford V Kernel exp 32 860 805C – – Stanford V... frame Destination Address A 6-byte field of the destination node address Source Address A 6-byte field of the source node address Data Contains transmission data to be processed by receiving station 182 • • • Frame Check Sequence (FCS) Similar to a CRC, the source station calculates a value based on the frame contents The destination station must recalculate the value based on a successful frame transmission... Source Address A 6-byte field of the source node address Data Contains transmission data to be processed by receiving station Frame Check Sequence (FCS) Similar to a CRC (described in Chapter 3) , the source station calculates a value based on the frame contents The destination station must recalculate the value based on a successful frame transmission The frame is discarded if the FCS of the source and... – – VG Analytical 172 82 03 8205 – – Quantum Software 8221–8222 – – Ascom Banking Systems 823E–8240 – – Advanced Encryption Syste 827F–8282 – – Athena Programming 82 63 82 6A – – Charles River Data System 82 9A 829B – – Inst Ind Info Tech 829C–82AB – – Taurus Controls 82AC–86 93 – – Walker Richer & Quinn 8694–869D – – Idea Courier 869E–8 6A1 – – Computer Network Tech 8 6A3 –86AC – – Gateway Communications... DCA Data Exchange Cluster 32 964 80C4 – – Banyan Systems 32 965 80C5 – – Banyan Systems 32 966 80C6 – – Pacer Software 32 967 80C7 – – Applitek Corporation 32 968 80C8–80CC – – Intergraph Corporation 170 32 9 73 80CD–80CE – – Harris Corporation 32 975 80CF–80D2 – – Taylor Instrument 32 979 80D3–80D4 – – Rosemount Corporation 32 981 80D5 – – IBM SNA Service on Ether 32 989 80DD – – Varian Associates 32 990 80DE–80DF... a station is ready for transmission, it captures the Token and sends the information in FDDI frames (see Figure 6.18) The FDDI format fields are defined as follows: Figure 6.18 FDDI frame format • • • • • • Preamble A sequence that prepares a station for upcoming frames Start Delimiter Announces the arrival of a token to each station Frame Control Indicates whether data or control information is carried... Media Access Control Addressing and Vendor Codes As discussed in previous chapters, the media access control (MAC) address is defined in the MAC sublayer of the Data Link layer of the OSI model The MAC address identifies the physical hardware network interface and is programmed in read-only memory (ROM) Each interface must have a unique address in order to participate on communication mediums, primarily... is a SNAP frame CTRL Control field Ethernet Type Indicates the data length of the frame Frame Data Indicates the data carried in the frame, based on the type latent in the Frame Type field Cyclic Redundancy Check (CRC) Helps detect transmission errors The sending station computes a frame value before transmission Upon frame retrieval, the receiving station must compute the same value based on a complete, . Symbolics Private 33 072 8 130 – – Hayes Microcomputers 33 0 73 8 131 – – VG Laboratory Systems 33 074 8 132 –8 136 – – Bridge Communications 33 079 8 137 –8 138 – – Novell, Inc. 33 081 8 139 –813D – – KTI. Datability 33 010 80F2 – – Retix 33 011 80F3 – – AppleTalk AARP (Kinetics) 33 012 80F4–80F5 – – Kinetics 33 015 80F7 – – Apollo Computer 33 0 23 80FF–81 03 – – Wellfleet Communications 33 031 8107–8109. 32 932 8 0A4 –80B3 – – Siemens Gammasonics Inc. 32 960 80C0–80C3 – – DCA Data Exchange Cluster 32 964 80C4 – – Banyan Systems 32 965 80C5 – – Banyan Systems 32 966 80C6 – – Pacer Software 32 967