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[原创] WMCTF2021 Re 部分复现
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2021-9-3 22:31
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WMCTF2021赛题复现
开局flutter，直呼内行
咕咕咕（bushi) 另外两题实在肝不动，等官方wp了
Re1
题目开局花指令常见花指令识别与处理方案 | 我的CTF学习笔记 (mas0n.cn)
去掉花指令后，正常F5，发现虚假控制流
对输入进行了条件约束
将起始下标定位到输入的WMCTF{后一位Str[6]，而后进入控制流顺序执行。
首先开辟了一块大小为576的内存空间，给地址为首先将Block指针转为DOWRD*,而后*(Block + 273) = 0xdead
进入case 0，取了前四位字符，循环写入了四段数据
而后运行至case 1，取四字符之后的16位，写入Block + 530对应的地址空间
而后就是运行case 2了，此时index已经是6 + 4 + 16，而分析case 2发现其对之后的每五位进行处理，最大能够处理三组数据。
五位中，第一位被拿来作为不同函数调用的标志，再分别将后四位十六进制字符转换成int类型，而后调用相关函数
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 | v7 = index++; str_7 = Str[v7]; // Str[27] if ( str_7 == '_' && index + 4 <= length ) { if ( (Str[index] < '0' || Str[index] > '9') && (Str[index] < 'A' || Str[index] > 'F') || (Str[index + 1] < '0' || Str[index + 1] > '9') && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < '0' || Str[index + 2] > '9') && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < '0' || Str[index + 3] > '9') && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v8 = index++; str_8 = Str[v8]; v9 = index++; str_9 = Str[v9]; str_10 = hex2int(str_8, str_9); // 十六进制转十进制 v10 = index++; str_8 = Str[v10]; v11 = index++; str_9 = Str[v11]; vars9B = hex2int(str_8, str_9); sub_140003320((__int64)Block, str_10, vars9B); } } else if ( str_7 == '@' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v12 = index++; str_8 = Str[v12]; v13 = index++; str_9 = Str[v13]; str_10 = hex2int(str_8, str_9); v14 = index++; str_8 = Str[v14]; v15 = index++; str_9 = Str[v15]; vars9B = hex2int(str_8, str_9); sub_140003390((__int64)Block, str_10, vars9B); } } else if ( str_7 == '#' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v16 = index++; str_8 = Str[v16]; v17 = index++; str_9 = Str[v17]; str_10 = hex2int(str_8, str_9); v18 = index++; str_8 = Str[v18]; v19 = index++; str_9 = Str[v19]; vars9B = hex2int(str_8, str_9); sub_1400033F0(Block, str_10, vars9B); } } else if ( str_7 == '?' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v20 = index++; str_8 = Str[v20]; v21 = index++; str_9 = Str[v21]; str_10 = hex2int(str_8, str_9); v22 = index++; str_8 = Str[v22]; v23 = index++; str_9 = Str[v23]; vars9B = hex2int(str_8, str_9); sub_140003470((__int64)Block, str_10, vars9B); } } else if ( str_7 == '!' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v24 = index++; str_8 = Str[v24]; v25 = index++; str_9 = Str[v25]; str_10 = hex2int(str_8, str_9); v26 = index++; str_8 = Str[v26]; v27 = index++; str_9 = Str[v27]; vars9B = hex2int(str_8, str_9); sub_140003500(Block, str_10, vars9B); } } else if ( str_7 == '&' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v28 = index++; str_8 = Str[v28]; v29 = index++; str_9 = Str[v29]; str_10 = hex2int(str_8, str_9); v30 = index++; str_8 = Str[v30]; v31 = index++; str_9 = Str[v31]; vars9B = hex2int(str_8, str_9); sub_140003580(Block, str_10, vars9B); } } else if ( str_7 == '-' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v32 = index++; str_8 = Str[v32]; v33 = index++; str_9 = Str[v33]; str_10 = hex2int(str_8, str_9); v34 = index++; str_8 = Str[v34]; v35 = index++; str_9 = Str[v35]; vars9B = hex2int(str_8, str_9); sub_1400035E0(Block, str_10, vars9B); } } else if ( str_7 == '$' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v36 = index++; str_8 = Str[v36]; v37 = index++; str_9 = Str[v37]; str_10 = hex2int(str_8, str_9); v38 = index++; str_8 = Str[v38]; v39 = index++; str_9 = Str[v39]; vars9B = hex2int(str_8, str_9); sub_1400036A0(Block, str_10, vars9B); } } else if ( str_7 == '+' && index + 4 <= length ) { if ( (Str[index] < 48 || Str[index] > 57) && (Str[index] < 65 || Str[index] > 70) || (Str[index + 1] < 48 || Str[index + 1] > 57) && (Str[index + 1] < 65 || Str[index + 1] > 70) || (Str[index + 2] < 48 || Str[index + 2] > 57) && (Str[index + 2] < 65 || Str[index + 2] > 70) || (Str[index + 3] < 48 || Str[index + 3] > 57) && (Str[index + 3] < 65 || Str[index + 3] > 70) ) { vars9A = 1; } else { v40 = index++; str_8 = Str[v40]; v41 = index++; str_9 = Str[v41]; str_10 = hex2int(str_8, str_9); v42 = index++; str_8 = Str[v42]; v43 = index++; str_9 = Str[v43]; vars9B = hex2int(str_8, str_9); sub_140003730((__int64)Block, str_10, vars9B); } } else { Block[str_7 + 257] += str_7; vars9A = 1; } break; |
理解不了，先放一放，看后面
分析后，发现，cond开头的四个参数可以通过z3求出，而且，其值源自boxXor，虽然它不可逆，但我们在分析case 0的时候就知道，Block，Block + 257……四段正好是由四个字符处理而来。
考虑爆破出4字符
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 | import z3cond1 = z3.BitVec("cond1", 32)cond2 = z3.BitVec("cond2", 32)cond3 = z3.BitVec("cond3", 32)cond4 = z3.BitVec("cond4", 32)result1 = cond2 + cond1 == 0x11AB7A7Aresult2 = cond2 - cond3 == 0x1CD4F222result3 = cond4 + cond3 == 0xC940F021result4 = cond3 + cond1 - cond4 == 0x7C7D68D1solve = z3.Solver()solve.add(result1)solve.add(result2)solve.add(result3)solve.add(result4)if solve.check() == z3.sat: m = solve.model() cond1 = m.eval(cond1).as_long() cond2 = m.eval(cond2).as_long() cond3 = m.eval(cond3).as_long() cond4 = m.eval(cond4).as_long()print(hex(cond1), hex(cond2), hex(cond3), hex(cond4))import stringbox = [0x00000000, 0x703A11DE, 0xE07423BC, 0x904E3262, 0xC6A99C09, 0xB6938DD7, 0x26DDBFB5, 0x56E7AE6B, 0x8B12E363, 0xFB28F2BD, 0x6B66C0DF, 0x1B5CD101, 0x4DBB7F6A, 0x3D816EB4, 0xADCF5CD6, 0xDDF54D08, 0x10641DB7, 0x605E0C69, 0xF0103E0B, 0x802A2FD5, 0xD6CD81BE, 0xA6F79060, 0x36B9A202, 0x4683B3DC, 0x9B76FED4, 0xEB4CEF0A, 0x7B02DD68, 0x0B38CCB6, 0x5DDF62DD, 0x2DE57303, 0xBDAB4161, 0xCD9150BF, 0x20C83B6E, 0x50F22AB0, 0xC0BC18D2, 0xB086090C, 0xE661A767, 0x965BB6B9, 0x061584DB, 0x762F9505, 0xABDAD80D, 0xDBE0C9D3, 0x4BAEFBB1, 0x3B94EA6F, 0x6D734404, 0x1D4955DA, 0x8D0767B8, 0xFD3D7666, 0x30AC26D9, 0x40963707, 0xD0D80565, 0xA0E214BB, 0xF605BAD0, 0x863FAB0E, 0x1671996C, 0x664B88B2, 0xBBBEC5BA, 0xCB84D464, 0x5BCAE606, 0x2BF0F7D8, 0x7D1759B3, 0x0D2D486D, 0x9D637A0F, 0xED596BD1, 0x419076DC, 0x31AA6702, 0xA1E45560, 0xD1DE44BE, 0x8739EAD5, 0xF703FB0B, 0x674DC969, 0x1777D8B7, 0xCA8295BF, 0xBAB88461, 0x2AF6B603, 0x5ACCA7DD, 0x0C2B09B6, 0x7C111868, 0xEC5F2A0A, 0x9C653BD4, 0x51F46B6B, 0x21CE7AB5, 0xB18048D7, 0xC1BA5909, 0x975DF762, 0xE767E6BC, 0x7729D4DE, 0x0713C500, 0xDAE68808, 0xAADC99D6, 0x3A92ABB4, 0x4AA8BA6A, 0x1C4F1401, 0x6C7505DF, 0xFC3B37BD, 0x8C012663, 0x61584DB2, 0x11625C6C, 0x812C6E0E, 0xF1167FD0, 0xA7F1D1BB, 0xD7CBC065, 0x4785F207, 0x37BFE3D9, 0xEA4AAED1, 0x9A70BF0F, 0x0A3E8D6D, 0x7A049CB3, 0x2CE332D8, 0x5CD92306, 0xCC971164, 0xBCAD00BA, 0x713C5005, 0x010641DB, 0x914873B9, 0xE1726267, 0xB795CC0C, 0xC7AFDDD2, 0x57E1EFB0, 0x27DBFE6E, 0xFA2EB366, 0x8A14A2B8, 0x1A5A90DA, 0x6A608104, 0x3C872F6F, 0x4CBD3EB1, 0xDCF30CD3, 0xACC91D0D, 0x8320EDB8, 0xF31AFC66, 0x6354CE04, 0x136EDFDA, 0x458971B1, 0x35B3606F, 0xA5FD520D, 0xD5C743D3, 0x08320EDB, 0x78081F05, 0xE8462D67, 0x987C3CB9, 0xCE9B92D2, 0xBEA1830C, 0x2EEFB16E, 0x5ED5A0B0, 0x9344F00F, 0xE37EE1D1, 0x7330D3B3, 0x030AC26D, 0x55ED6C06, 0x25D77DD8, 0xB5994FBA, 0xC5A35E64, 0x1856136C, 0x686C02B2, 0xF82230D0, 0x8818210E, 0xDEFF8F65, 0xAEC59EBB, 0x3E8BACD9, 0x4EB1BD07, 0xA3E8D6D6, 0xD3D2C708, 0x439CF56A, 0x33A6E4B4, 0x65414ADF, 0x157B5B01, 0x85356963, 0xF50F78BD, 0x28FA35B5, 0x58C0246B, 0xC88E1609, 0xB8B407D7, 0xEE53A9BC, 0x9E69B862, 0x0E278A00, 0x7E1D9BDE, 0xB38CCB61, 0xC3B6DABF, 0x53F8E8DD, 0x23C2F903, 0x75255768, 0x051F46B6, 0x955174D4, 0xE56B650A, 0x389E2802, 0x48A439DC, 0xD8EA0BBE, 0xA8D01A60, 0xFE37B40B, 0x8E0DA5D5, 0x1E4397B7, 0x6E798669, 0xC2B09B64, 0xB28A8ABA, 0x22C4B8D8, 0x52FEA906, 0x0419076D, 0x742316B3, 0xE46D24D1, 0x9457350F, 0x49A27807, 0x399869D9, 0xA9D65BBB, 0xD9EC4A65, 0x8F0BE40E, 0xFF31F5D0, 0x6F7FC7B2, 0x1F45D66C, 0xD2D486D3, 0xA2EE970D, 0x32A0A56F, 0x429AB4B1, 0x147D1ADA, 0x64470B04, 0xF4093966, 0x843328B8, 0x59C665B0, 0x29FC746E, 0xB9B2460C, 0xC98857D2, 0x9F6FF9B9, 0xEF55E867, 0x7F1BDA05, 0x0F21CBDB, 0xE278A00A, 0x9242B1D4, 0x020C83B6, 0x72369268, 0x24D13C03, 0x54EB2DDD, 0xC4A51FBF, 0xB49F0E61, 0x696A4369, 0x195052B7, 0x891E60D5, 0xF924710B, 0xAFC3DF60, 0xDFF9CEBE, 0x4FB7FCDC, 0x3F8DED02, 0xF21CBDBD, 0x8226AC63, 0x12689E01, 0x62528FDF, 0x34B521B4, 0x448F306A, 0xD4C10208, 0xA4FB13D6, 0x790E5EDE, 0x09344F00, 0x997A7D62, 0xE9406CBC, 0xBFA7C2D7, 0xCF9DD309, 0x5FD3E16B, 0x2FE9F0B5]def boxXor(a1, a2, a3): v5 = 0 v4 = a1 while v5 < a3: v4 = (v4 >> 8) ^ box[(a2[v5] ^ v4) & 0xff] v5 += 1 return a1 ^ v4def genBlock(a1, a2, a3): block = [] for i in range(a3): block.append(i + a1 + a2) return blockcond0 = 0xFFFFFFFEfor c in string.printable: block = genBlock(ord(c), 0, 256) cond = boxXor(cond0, block, 256) if cond == cond1: print("find Str[7]: " + c)for c in string.printable: block = genBlock(ord(c), 1, 256) cond = boxXor(cond1, block, 256) if cond == cond2: print("find Str[8]: " + c)for c in string.printable: block = genBlock(ord(c), 2, 0xf) cond = boxXor(cond2, block, 0xf) if cond == cond3: print("find Str[9]: " + c)for c in string.printable: block = genBlock(ord(c), 3, 0x1c) cond = boxXor(cond3, block, 0x1c) if cond == cond4: print("find Str[9]: " + c)# Hah4 |
爆破得到Hah4
而后在上图也可以看到，我分析后标注了xteaEncrypt函数，key和src,但同时我也注释了两个unknown，为什么？后面再讲。
第一时间，当我们看到
很快能够想到之前case 0似乎有出现给Block + 273这一地址空间赋值0xdead
于是我们尝试解密，发现并不是可见字符——key是错误的。
0~0xffff尝试爆破出真正的值
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | #include <stdio.h>#include <stdint.h>#include <string.h>#include <windows.h>#include <iostream>void xteaEnc(DWORD *v, DWORD *kj, DWORD *a3){ unsigned int *result; // rax unsigned int v4; // [rsp+0h] [rbp-30h] unsigned int v5; // [rsp+Ch] [rbp-24h] unsigned int v6; // [rsp+10h] [rbp-20h] unsigned int i; // [rsp+14h] [rbp-1Ch] v6 = *v; v5 = v[1]; v4 = 0; for ( i = 0; i < 0x20; ++i ) { v6 += (kj[v4 & 3] + v4) ^ (v5 + ((v5 >> 5) ^ (16 * v5))); v4 -= 0x667E5433; v5 += (kj[(v4 >> 11) & 3] + v4) ^ (v6 + ((v6 >> 5) ^ (16 * v6))); } *a3 = v6; a3[1] = v5;}void xteaDec(DWORD *v, DWORD *kj, DWORD *a3){ unsigned int *result; // rax unsigned int v4; // [rsp+0h] [rbp-30h] unsigned int v5; // [rsp+Ch] [rbp-24h] unsigned int v6; // [rsp+10h] [rbp-20h] unsigned int i; // [rsp+14h] [rbp-1Ch] v6 = *v; v5 = v[1]; v4 = 0x303579a0; for ( i = 0; i < 0x20; ++i ) { v5 -= (kj[(v4 >> 11) & 3] + v4) ^ (v6 + ((v6 >> 5) ^ (16 * v6))); v4 += 0x667E5433; v6 -= (kj[v4 & 3] + v4) ^ (v5 + ((v5 >> 5) ^ (16 * v5))); } *a3 = v6; a3[1] = v5;}void DWORD2BYTE(uint8_t* Dst, uint64_t Value, const std::string& byteorder) { /* ============================ * byteorder = "big" / "little" * */ if (byteorder == "big") { // big for (int i = 0; i < 4; ++i) { Dst[3 - i] = Value & 0xff; Value >>= 8; } } else if (byteorder == "little") { // little for (int i = 0; i < 4; ++i) { Dst[i] = Value & 0xff; Value >>= 8; } } else { perror("plz check byteorder"); }}void fuzzing() { DWORD P1 = 0xa3eeb7be, P2 = 0x6dbcc2bc, P3 = 0x50e7d09a, P4 = 0x78591f87; DWORD plaintext[2] = {0x556E2853, 0x4393DF16}; for (int fuz = 0; fuz < 0x10000; ++fuz) { DWORD vars7C = P4 & 0xFFFFFF00 | (unsigned __int8)fuz; P3 &= 0xFFFF00FF; P3 |= fuz & 0xFF00; DWORD key[4] = {P1, P3, P2, vars7C}; DWORD result[2]; xteaDec(plaintext, key, result); BYTE flag[9] = {0}; DWORD2BYTE(flag, result[0], "little"); DWORD2BYTE(&flag[4], result[1], "little"); int find = 1; for (int i = 0; i < 8; ++i) { if (flag[i] > 'z' || flag[i] < ' ') { find = 0; break; } } if (find) { printf("bytes: %x FLAG: %s\n", fuz, flag); } }}int main(){ fuzzing(); return 0;} |
看到明文
尝试解密
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | int main(){ DWORD P1 = 0xa3eeb7be, P2 = 0x6dbcc2bc, P3 = 0x50e7d09a, P4 = 0x78591f87; DWORD vars7C = P4 & 0xFFFFFF00 | (unsigned __int8)0xb7ad; // 不知道对不对 P3 &= 0xFFFF00FF; P3 |= 0xb7ad & 0xFF00; // todo: unknown DWORD plaintext[2] = {0x556E2853, 0x4393DF16}; DWORD key[4] = {P1, P3, P2, vars7C}; DWORD result[2]; xteaDec(plaintext, key, result); printf("%lx %lx\n", result[0], result[1]); DWORD plaintext2[2] = {0x1989FB2B, 0x83F5A243}; DWORD key2[4] = {vars7C, P2, P1, P3}; DWORD result2[2]; xteaDec(plaintext2, key2, result2); printf("%lx %lx\n", result2[0], result2[1]); BYTE flag[17] = {0}; DWORD2BYTE(flag, result[0], "little"); DWORD2BYTE(&flag[4], result2[0], "little"); DWORD2BYTE(&flag[8], result2[1], "little"); DWORD2BYTE(&flag[12], result[1], "little"); printf("%s\n", flag); printf("%08lx %08lx %08lx %08lx\n", result[0], result2[0], result2[1] ,result[1]); return 0;} |
得到_D0_yOu_L1kE_It!
现在我们拿到了前半段flag，下面就是考虑如何拿到后半段flag
切入点：Block + 273
既然Block + 273被修改了，猜测是在case 2执行过程中修改了它
分析各个函数，想办法能够修改到Block + 273
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 | // @FF FE // #0F 20// -11 B7Block[546] = 0xDEAD;Block[256] = 0xfe;Block[528] = 0x20;Block[547] = 0xb7;// ___int64 __fastcall sub_140003320(__int64 a1, unsigned __int8 a2, char a3){ __int64 result; // rax result = (unsigned int)(dword_140027A50 + 1); dword_140027A50 = result; if ( (unsigned int)result <= 1 ) { result = a1 + 548; *(_BYTE *)(a1 + 548 + ((int)a2 >> 4) + 1) = a3;// 549 ~ 565 } return result;}// @__int64 __fastcall sub_140003390(__int64 a1, char a2, char a3){ __int64 result; // rax result = (unsigned int)(dword_140027A54 + 1); dword_140027A54 = result; if ( (unsigned int)result <= 1 ) { result = a1 + 257; *(_BYTE *)(a1 + 257 + a2) = a3; // 注意-1溢出 - 256 } return result;}// #__int64 __fastcall sub_1400033F0(_BYTE *a1, char a2, char a3){ __int64 result; // rax result = (unsigned int)(dword_140027A50 + 1); dword_140027A50 = result; if ( (unsigned int)result <= 1 ) { result = (unsigned __int8)a1[256]; if ( (_DWORD)result == 0xFE ) { result = (unsigned int)a2; if ( (int)result < 0x10 ) { result = (__int64)(a1 + 513); a1[a2 + 513] = a3; // 513 ~ 768 528 } } } return result;}// ?__int64 __fastcall sub_140003470(__int64 a1, char a2, char a3){ __int64 result; // rax result = (unsigned int)(dword_140027A58 + 1); dword_140027A58 = result; if ( (unsigned int)result <= 1 ) { result = *(unsigned __int16 *)(a1 + 528) / 3; if ( !(*(unsigned __int16 *)(a1 + 528) % 3) ) { result = a1 + 530; *(_BYTE *)(a1 + 530 + (a2 & 0xC)) = a3; // 530 ~ 542 -> 530, 534, 538, 542 } } return result;}// -__int64 __fastcall sub_1400035E0(_BYTE *a1, char a2, char a3){ __int64 result; // rax result = (unsigned int)(dword_140027A60 + 1); dword_140027A60 = result; if ( (unsigned int)result <= 1 ) { result = *((unsigned __int16 *)a1 + 264) / 16; // a1[528] if ( !(*((unsigned __int16 *)a1 + 264) % 16) ) { result = *((unsigned __int16 *)a1 + 264) / 16; if ( (unsigned int)(*((unsigned __int16 *)a1 + 264) / 16) < 3 ) { result = (unsigned int)a2; if ( (int)result <= *((unsigned __int16 *)a1 + 264) ) { result = (__int64)(a1 + 530); a1[a2 + 530] = a3; } } } } return result;} |
这里就需要试着套流程 ，依靠脑洞了- -
最后得到@FFFE#0F20-11B7
tips: 这里的@，用到了一个0xff的溢出（-1）
Re2
android题，主逻辑一如既往在ndk
动态注册的函数调用。
先瞟一眼.init_array
看起来是加了混淆
再看JNI_OnLoad
发现一个出题者挖的坑，检测了调试机的root
试了试frida直接hook，结果hook不住……（有知道为啥的大佬教一下我）那就直接patch so吧
打包回去，安装
尴尬，改一下AndroidManifest.xml里的android:extractNativeLibs
再来
调试环境整好，下面先静态分析一下。
程序的正常流程是在这里注册
注册的函数为sub_10134
分析出来，先进行了AES加密而后进行RC4，这里的算法都是经过一定的魔改，并不是标准算法。
最后与stru_46000[0].n128_u8[v11]比对
KeyExpansion是标准的密钥扩展算法，AES主要的修改点在于Sbox和ShiftRows部分
而RC4的修改，在于最后异或时多异或了0x50
算法是分析完了，那么如何拿到AES Key，IV和RC4Key?
我们前面看到.init_array是对一些数据的解密，静态提取是不可取了，那就动态跑起来取，Frida Hook（动态调试So也是可以的）
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | function awaitHook() { Java.perform(function(){ var ptr = Module.findBaseAddress("libnative-lib.so"); if(ptr==null){ return 0;} Interceptor.attach(ptr.add(0x011E6C),{ onEnter:function(arg){ console.log("\nHooking - AESEncrypt - IV: \n" + hexdump(arg[0].add(176), {length:16})); console.log("\nHooking - AESEncrypt - Text: \n" + arg[1].readCString()); }, onLeave:function(arg){ console.log("\nHooking - AESEncrypt - EncText: \n", hexdump(arg, {length:32})); console.log("Hooking - AESEncrypt - EXIT"); } }) Interceptor.attach(ptr.add(0x00011820), { onEnter: function(args) { console.log("\narg[1] - AESKey\n" + hexdump(args[1], {length:16})); }, onLeave: function(arg) { // console.log("leave"); } }) })}setImmediate(function(){ setTimeout(awaitHook,10);})// frida -U come.wmctf.crackme111 -l ctf.js --no-pause |
下面继续取RC4的Key
1 2 3 4 5 6 7 8 | Interceptor.attach(ptr.add(0x011624), { onEnter: function(args) { console.log("\narg[1] - RC4Key\n" + args[1].readCString()); }, onLeave: function(arg) { // console.log("leave"); } }) |
拿到RC4Key：Hello from C++
再去Hook比对的加密文本
1 | console.log("hooking - EncData[32]\n", hexdump(ptr.add(0x046000),{length:32})); |
撸脚本解密了
1 2 3 4 5 6 7 8 9 10 11 | from Crypto.Cipher import ARC4rc4CipherText = bytearray(bytes.fromhex("18 76 eb 87 76 3e 77 08 c0 8d 56 25 9e 35 0d 16 23 65 61 6a 14 9d 4f 1c 64 21 7d 78 ba 53 91 22")) for i, v in enumerate(rc4CipherText): rc4CipherText[i] = v ^ 0x50key = "Hello from C++"rc4 = ARC4.new(key.encode())aesCipherText = rc4.decrypt(rc4CipherText).hex()print(aesCipherText) |
拿出Sbox，跑出InvBox，修改ShiftRows
aes.cpp
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 | #include <stdio.h>#include <memory.h>#include "AES.h"//// Public Definitions///* moved to rijndael.h *///// Internal Definitions///* * Encryption Rounds */int g_aes_key_bits[] = { /* AES_CYPHER_128 */ 128, /* AES_CYPHER_192 */ 192, /* AES_CYPHER_256 */ 256, };int g_aes_rounds[] = { /* AES_CYPHER_128 */ 10, /* AES_CYPHER_192 */ 12, /* AES_CYPHER_256 */ 14, };int g_aes_nk[] = { /* AES_CYPHER_128 */ 4, /* AES_CYPHER_192 */ 6, /* AES_CYPHER_256 */ 8, };int g_aes_nb[] = { /* AES_CYPHER_128 */ 4, /* AES_CYPHER_192 */ 4, /* AES_CYPHER_256 */ 4, };/* * aes Rcon: * * WARNING: Rcon is designed starting from 1 to 15, not 0 to 14. * FIPS-197 Page 9: "note that i starts at 1, not 0" * * i | 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 * -----+------------------------------------------------------------------------------------------ * | [01] [02] [04] [08] [10] [20] [40] [80] [1b] [36] [6c] [d8] [ab] [4d] [9a] * RCON | [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] * | [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] * | [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] [00] */static const uint32_t g_aes_rcon[] = { 0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000, 0x20000000, 0x40000000, 0x80000000, 0x1b000000, 0x36000000, 0x6c000000, 0xd8000000, 0xab000000, 0xed000000, 0x9a000000};/* aes sbox and invert-sbox */static const uint8_t g_aes_sbox[256] = { /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */ 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16};static const uint8_t g_inv_sbox[256] = { /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */ 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbe, 0x40, 0xa3, 0x9e, 0x80, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, 0x90, 0xd8, 0xab, 0x02, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x04, 0xc1, 0xaf, 0xbd, 0x03, 0x00, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbf, 0x1b, 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x81, 0xec, 0x5f, 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, 0x17, 0x2b, 0x01, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d};uint8_t aes_sub_sbox(uint8_t val){ return g_aes_sbox[val];}uint32_t aes_sub_dword(uint32_t val){ uint32_t tmp = 0; tmp |= ((uint32_t)aes_sub_sbox((uint8_t)((val >> 0) & 0xFF))) << 0; tmp |= ((uint32_t)aes_sub_sbox((uint8_t)((val >> 8) & 0xFF))) << 8; tmp |= ((uint32_t)aes_sub_sbox((uint8_t)((val >> 16) & 0xFF))) << 16; tmp |= ((uint32_t)aes_sub_sbox((uint8_t)((val >> 24) & 0xFF))) << 24; return tmp;}uint32_t aes_rot_dword(uint32_t val){ uint32_t tmp = val; return (val >> 8) | ((tmp & 0xFF) << 24);}uint32_t aes_swap_dword(uint32_t val){ return (((val & 0x000000FF) << 24) | ((val & 0x0000FF00) << 8) | ((val & 0x00FF0000) >> 8) | ((val & 0xFF000000) >> 24) );}/* * nr: number of rounds * nb: number of columns comprising the state, nb = 4 dwords (16 bytes) * nk: number of 32-bit words comprising cipher key, nk = 4, 6, 8 (KeyLength/(4*8)) */void aes_key_expansion(AES_CYPHER_T mode, uint8_t *key, uint8_t *round){ uint32_t *w = (uint32_t *)round; uint32_t t; int i = 0; printf("Key Expansion:\n"); do { w[i] = *((uint32_t *)&key[i * 4 + 0]); printf(" %2.2d: rs: %8.8x\n", i, aes_swap_dword(w[i])); } while (++i < g_aes_nk[mode]); do { printf(" %2.2d: ", i); if ((i % g_aes_nk[mode]) == 0) { t = aes_rot_dword(w[i - 1]); printf(" rot: %8.8x", aes_swap_dword(t)); t = aes_sub_dword(t); printf(" sub: %8.8x", aes_swap_dword(t)); printf(" rcon: %8.8x", g_aes_rcon[i/g_aes_nk[mode] - 1]); t = t ^ aes_swap_dword(g_aes_rcon[i/g_aes_nk[mode] - 1]); printf(" xor: %8.8x", t); } else if (g_aes_nk[mode] > 6 && (i % g_aes_nk[mode]) == 4) { t = aes_sub_dword(w[i - 1]); printf(" sub: %8.8x", aes_swap_dword(t)); } else { t = w[i - 1]; printf(" equ: %8.8x", aes_swap_dword(t)); } w[i] = w[i - g_aes_nk[mode]] ^ t; printf(" rs: %8.8x\n", aes_swap_dword(w[i])); } while (++i < g_aes_nb[mode] * (g_aes_rounds[mode] + 1)); /* key can be discarded (or zeroed) from memory */}void aes_add_round_key(AES_CYPHER_T mode, uint8_t *state, uint8_t *round, int nr){ uint32_t *w = (uint32_t *)round; uint32_t *s = (uint32_t *)state; int i; for (i = 0; i < g_aes_nb[mode]; i++) { s[i] ^= w[nr * g_aes_nb[mode] + i]; }}void aes_sub_bytes(AES_CYPHER_T mode, uint8_t *state){ int i, j; for (i = 0; i < g_aes_nb[mode]; i++) { for (j = 0; j < 4; j++) { state[i * 4 + j] = aes_sub_sbox(state[i * 4 + j]); } }}void aes_shift_rows(AES_CYPHER_T mode, uint8_t *state){ uint8_t *s = (uint8_t *)state; int i, j, r; for (i = 1; i < g_aes_nb[mode]; i++) { for (j = 0; j < i; j++) { uint8_t tmp = s[i]; for (r = 0; r < g_aes_nb[mode]; r++) { s[i + r * 4] = s[i + (r + 1) * 4]; } s[i + (g_aes_nb[mode] - 1) * 4] = tmp; } }}uint8_t aes_xtime(uint8_t x){ return ((x << 1) ^ (((x >> 7) & 1) * 0x1b));}uint8_t aes_xtimes(uint8_t x, int ts){ while (ts-- > 0) { x = aes_xtime(x); } return x;}uint8_t aes_mul(uint8_t x, uint8_t y){ /* * encrypt: y has only 2 bits: can be 1, 2 or 3 * decrypt: y could be any value of 9, b, d, or e */ return ((((y >> 0) & 1) * aes_xtimes(x, 0)) ^ (((y >> 1) & 1) * aes_xtimes(x, 1)) ^ (((y >> 2) & 1) * aes_xtimes(x, 2)) ^ (((y >> 3) & 1) * aes_xtimes(x, 3)) ^ (((y >> 4) & 1) * aes_xtimes(x, 4)) ^ (((y >> 5) & 1) * aes_xtimes(x, 5)) ^ (((y >> 6) & 1) * aes_xtimes(x, 6)) ^ (((y >> 7) & 1) * aes_xtimes(x, 7)) );}void aes_mix_columns(AES_CYPHER_T mode, uint8_t *state){ uint8_t y[16] = { 2, 3, 1, 1, 1, 2, 3, 1, 1, 1, 2, 3, 3, 1, 1, 2}; uint8_t s[4]; int i, j, r; for (i = 0; i < g_aes_nb[mode]; i++) { for (r = 0; r < 4; r++) { s[r] = 0; for (j = 0; j < 4; j++) { s[r] = s[r] ^ aes_mul(state[i * 4 + j], y[r * 4 + j]); } } for (r = 0; r < 4; r++) { state[i * 4 + r] = s[r]; } }}void aes_dump(char *msg, uint8_t *data, int len){ int i; printf("%8.8s: ", msg); for (i = 0; i < len; i++) { printf(" %2.2x", data[i]); } printf("\n");}int aes_encrypt(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key){ uint8_t w[4 * 4 * 15] = {0}; /* round key */ uint8_t s[4 * 4] = {0}; /* state */ int nr, i, j; /* key expansion */ aes_key_expansion(mode, key, w); /* start data cypher loop over input buffer */ for (i = 0; i < len; i += 4 * g_aes_nb[mode]) { printf("Encrypting block at %u ...\n", i); /* init state from user buffer (plaintext) */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) s[j] = data[i + j]; /* start AES cypher loop over all AES rounds */ for (nr = 0; nr <= g_aes_rounds[mode]; nr++) { printf(" Round %d:\n", nr); aes_dump("input", s, 4 * g_aes_nb[mode]); if (nr > 0) { /* do SubBytes */ aes_sub_bytes(mode, s); aes_dump(" sub", s, 4 * g_aes_nb[mode]); /* do ShiftRows */ aes_shift_rows(mode, s); aes_dump(" shift", s, 4 * g_aes_nb[mode]); if (nr < g_aes_rounds[mode]) { /* do MixColumns */ aes_mix_columns(mode, s); aes_dump(" mix", s, 4 * g_aes_nb[mode]); } } /* do AddRoundKey */ aes_add_round_key(mode, s, w, nr); aes_dump(" round", &w[nr * 4 * g_aes_nb[mode]], 4 * g_aes_nb[mode]); aes_dump(" state", s, 4 * g_aes_nb[mode]); } /* save state (cypher) to user buffer */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) data[i + j] = s[j]; printf("Output:\n"); aes_dump("cypher", &data[i], 4 * g_aes_nb[mode]); } return 0;}int aes_encrypt_ecb(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key){ return aes_encrypt(mode, data, len, key);}int aes_encrypt_cbc(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key, uint8_t *iv){ uint8_t w[4 * 4 * 15] = {0}; /* round key */ uint8_t s[4 * 4] = {0}; /* state */ uint8_t v[4 * 4] = {0}; /* iv */ int nr, i, j; /* key expansion */ aes_key_expansion(mode, key, w); memcpy(v, iv, sizeof(v)); /* start data cypher loop over input buffer */ for (i = 0; i < len; i += 4 * g_aes_nb[mode]) { /* init state from user buffer (plaintext) */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) s[j] = data[i + j] ^ v[j]; /* start AES cypher loop over all AES rounds */ for (nr = 0; nr <= g_aes_rounds[mode]; nr++) { aes_dump("input", s, 4 * g_aes_nb[mode]); if (nr > 0) { /* do SubBytes */ aes_sub_bytes(mode, s); aes_dump(" sub", s, 4 * g_aes_nb[mode]); /* do ShiftRows */ aes_shift_rows(mode, s); aes_dump(" shift", s, 4 * g_aes_nb[mode]); if (nr < g_aes_rounds[mode]) { /* do MixColumns */ aes_mix_columns(mode, s); aes_dump(" mix", s, 4 * g_aes_nb[mode]); } } /* do AddRoundKey */ aes_add_round_key(mode, s, w, nr); aes_dump(" round", &w[nr * 4 * g_aes_nb[mode]], 4 * g_aes_nb[mode]); aes_dump(" state", s, 4 * g_aes_nb[mode]); } /* save state (cypher) to user buffer */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) data[i + j] = v[j] = s[j]; } return 0;}void inv_shift_rows(AES_CYPHER_T mode, uint8_t *state){ // uint8_t *s = (uint8_t *)state; // int i, j, r; // // for (i = 1; i < g_aes_nb[mode]; i++) { // for (j = 0; j < g_aes_nb[mode] - i; j++) { // uint8_t tmp = s[i]; // for (r = 0; r < g_aes_nb[mode]; r++) { // s[i + r * 4] = s[i + (r + 1) * 4]; // } // s[i + (g_aes_nb[mode] - 1) * 4] = tmp; // } // } uint8_t result[16]; *result = *(state+0); // result[0] = s[0] result[4] = *(state+4); // result[4] = s[4] result[8] = *(state+8); // result[8] = s[8] result[12] = *(state+12); // result[12] = s[12] result[5] = *(state+1); // result[1] = s[5] result[9] = *(state+5); // result[5] = s[9] result[13] = *(state+9); // result[9] = s[13] result[1] = *(state+13); // result[13] = s[1] result[10] = *(state+2); // result[2] = s[10] result[2] = *(state+10); // result[10] = s[2] result[14] = *(state+6); // result[6] = s[14] result[6] = *(state+14); // result[14] = s[6] result[15] = *(state+3); // result[3] = s[15] result[11] = *(state+15); // result[15] = s[11] result[7] = *(state+11); // result[11] = s[7] result[3] = *(state+7); // result[7] = s[3] for(int i=0;i<16;i++) state[i]=result[i];} uint8_t inv_sub_sbox(uint8_t val){ return g_inv_sbox[val];}void inv_sub_bytes(AES_CYPHER_T mode, uint8_t *state){ int i, j; for (i = 0; i < g_aes_nb[mode]; i++) { for (j = 0; j < 4; j++) { state[i * 4 + j] = inv_sub_sbox(state[i * 4 + j]); } }}void inv_mix_columns(AES_CYPHER_T mode, uint8_t *state){ uint8_t y[16] = { 0x0e, 0x0b, 0x0d, 0x09, 0x09, 0x0e, 0x0b, 0x0d, 0x0d, 0x09, 0x0e, 0x0b, 0x0b, 0x0d, 0x09, 0x0e}; uint8_t s[4]; int i, j, r; for (i = 0; i < g_aes_nb[mode]; i++) { for (r = 0; r < 4; r++) { s[r] = 0; for (j = 0; j < 4; j++) { s[r] = s[r] ^ aes_mul(state[i * 4 + j], y[r * 4 + j]); } } for (r = 0; r < 4; r++) { state[i * 4 + r] = s[r]; } }}int aes_decrypt(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key){ uint8_t w[4 * 4 * 15] = {0}; /* round key */ uint8_t s[4 * 4] = {0}; /* state */ int nr, i, j; /* key expansion */ aes_key_expansion(mode, key, w); /* start data cypher loop over input buffer */ for (i = 0; i < len; i += 4 * g_aes_nb[mode]) { printf("Decrypting block at %u ...\n", i); /* init state from user buffer (cyphertext) */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) s[j] = data[i + j]; /* start AES cypher loop over all AES rounds */ for (nr = g_aes_rounds[mode]; nr >= 0; nr--) { printf(" Round %d:\n", nr); aes_dump("input", s, 4 * g_aes_nb[mode]); /* do AddRoundKey */ aes_add_round_key(mode, s, w, nr); aes_dump(" round", &w[nr * 4 * g_aes_nb[mode]], 4 * g_aes_nb[mode]); if (nr > 0) { if (nr < g_aes_rounds[mode]) { aes_dump(" mix", s, 4 * g_aes_nb[mode]); /* do MixColumns */ inv_mix_columns(mode, s); } /* do ShiftRows */ aes_dump(" shift", s, 4 * g_aes_nb[mode]); inv_shift_rows(mode, s); /* do SubBytes */ aes_dump(" sub", s, 4 * g_aes_nb[mode]); inv_sub_bytes(mode, s); } aes_dump(" state", s, 4 * g_aes_nb[mode]); } /* save state (cypher) to user buffer */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) data[i + j] = s[j]; printf("Output:\n"); aes_dump("plain", &data[i], 4 * g_aes_nb[mode]); } return 0;}int aes_decrypt_ecb(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key){ return aes_decrypt(mode, data, len, key);}int aes_decrypt_cbc(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key, uint8_t *iv){ uint8_t w[4 * 4 * 15] = {0}; /* round key */ uint8_t s[4 * 4] = {0}; /* state */ uint8_t v[4 * 4] = {0}; /* iv */ int nr, i, j; /* key expansion */ aes_key_expansion(mode, key, w); memcpy(v, iv, sizeof(v)); /* start data cypher loop over input buffer */ for (i = 0; i < len; i += 4 * g_aes_nb[mode]) { /* init state from user buffer (cyphertext) */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) s[j] = data[i + j]; /* start AES cypher loop over all AES rounds */ for (nr = g_aes_rounds[mode]; nr >= 0; nr--) { aes_dump("input", s, 4 * g_aes_nb[mode]); /* do AddRoundKey */ aes_add_round_key(mode, s, w, nr); aes_dump(" round", &w[nr * 4 * g_aes_nb[mode]], 4 * g_aes_nb[mode]); if (nr > 0) { if (nr < g_aes_rounds[mode]) { aes_dump(" mix", s, 4 * g_aes_nb[mode]); /* do MixColumns */ inv_mix_columns(mode, s); } /* do ShiftRows */ aes_dump(" shift", s, 4 * g_aes_nb[mode]); inv_shift_rows(mode, s); /* do SubBytes */ aes_dump(" sub", s, 4 * g_aes_nb[mode]); inv_sub_bytes(mode, s); } aes_dump(" state", s, 4 * g_aes_nb[mode]); } /* save state (cypher) to user buffer */ for (j = 0; j < 4 * g_aes_nb[mode]; j++) { uint8_t p = s[j] ^ v[j]; v[j] = data[i + j]; data[i + j] = p; } } return 0;}void aes_cypher_128_test(){#if 1 uint8_t buf[] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }; uint8_t key[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f };#else uint8_t buf[] = { 0x32, 0x43, 0xf6, 0xa8, 0x88, 0x5a, 0x30, 0x8d, 0x31, 0x31, 0x98, 0xa2, 0xe0, 0x37, 0x07, 0x34 }; uint8_t key[] = { 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c };#endif printf("\nAES_CYPHER_128 encrypt test case:\n"); printf("Input:\n"); aes_dump("data", buf, sizeof(buf)); aes_dump("key ", key, sizeof(key)); aes_encrypt(AES_CYPHER_128, buf, sizeof(buf), key); printf("\nAES_CYPHER_128 decrypt test case:\n"); printf("Input:\n"); aes_dump("data", buf, sizeof(buf)); aes_dump("key ", key, sizeof(key)); aes_decrypt(AES_CYPHER_128, buf, sizeof(buf), key);}void aes_cypher_192_test(){ uint8_t buf[] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }; uint8_t key[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17 }; printf("\nAES_CYPHER_192 encrypt test case:\n"); printf("Input:\n"); aes_dump("data", buf, sizeof(buf)); aes_dump("key ", key, sizeof(key)); aes_encrypt(AES_CYPHER_192, buf, sizeof(buf), key); printf("\nAES_CYPHER_192 decrypt test case:\n"); printf("Input:\n"); aes_dump("data", buf, sizeof(buf)); aes_dump("key ", key, sizeof(key)); aes_decrypt(AES_CYPHER_192, buf, sizeof(buf), key);}void aes_cypher_256_test(){ uint8_t buf[] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }; uint8_t key[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f}; printf("\nAES_CYPHER_256 encrypt test case:\n"); printf("Input:\n"); aes_dump("data", buf, sizeof(buf)); aes_dump("key ", key, sizeof(key)); aes_encrypt(AES_CYPHER_256, buf, sizeof(buf), key); printf("\nAES_CYPHER_256 decrypt test case:\n"); printf("Input:\n"); aes_dump("data", buf, sizeof(buf)); aes_dump("key ", key, sizeof(key)); aes_decrypt(AES_CYPHER_256, buf, sizeof(buf), key);} |
AES.h
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | #ifdef __cplusplusextern "C" {#endif typedef enum { AES_CYPHER_128, AES_CYPHER_192, AES_CYPHER_256, } AES_CYPHER_T;#ifdef _MSC_VER #if _MSC_VER >= 1600 #include <cstdint> #else typedef __int8 int8_t; typedef __int16 int16_t; typedef __int32 int32_t; typedef __int64 int64_t; typedef unsigned __int8 uint8_t; typedef unsigned __int16 uint16_t; typedef unsigned __int32 uint32_t; typedef unsigned __int64 uint64_t; #endif#elif __GNUC__ >= 3 #include <cstdint>#endif int aes_encrypt_ecb(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key); int aes_decrypt_ecb(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key); int aes_encrypt_cbc(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key, uint8_t *iv); int aes_decrypt_cbc(AES_CYPHER_T mode, uint8_t *data, int len, uint8_t *key, uint8_t *iv);#ifdef __cplusplus};#endif |
main.cpp
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | #include <stdio.h>#include "AES.h"static void pchar(uint8_t* str){ unsigned char i; for (i = 0; i < 32; ++i) printf("%c", str[i]); printf("\n");}int main(int argc, char *argv[]) { /* 128 bit key */ uint8_t key[16] = { 0x54, 0x72, 0x61, 0x63, 0x65, 0x72, 0x50, 0x69, 0x64, 0x3a, 0x09, 0x30, 0x0a, 0x66, 0x6c, 0x67 }; uint8_t iv[16] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }; uint8_t ciphertext[32] = { 0xd0, 0x60, 0xf7, 0xc6, 0x95, 0x42, 0x22, 0xfd, 0xe3, 0x6b, 0x7e, 0x9c, 0xa1, 0xc9, 0xd8, 0xfa, 0xcf, 0x82, 0xc8, 0x76, 0xf8, 0xcb, 0x7c, 0x6f, 0xf8, 0x7f, 0x99, 0x5a, 0x12, 0x62, 0xc6, 0xb6 }; uint8_t plaintext[32]; aes_decrypt_cbc(AES_CYPHER_128, ciphertext,32 , key, iv); pchar(ciphertext); printf("\n"); return 0;} |
解出flag：wmctf{e78ce1a3ac4be37a96e27e98c}
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