端口扫描是指某些别有用心的人发送一组端口扫描消息,试图以此侵入某台计算机,并了解其提供的计算机网络服务类型(这些网络服务均与端口号相关)。端口扫描是计算机解密高手喜欢的一种方式。攻击者可以通过它了解到从哪里可探寻到攻击弱点。实质上,端口扫描包括向每个端口发送消息,一次只发送一个消息。接收到的回应类型表示是否在使用该端口并且可由此探寻弱点。 扫描器是一种自动检测远程或本地主机安全性弱点的程序,通过使用扫描器你可以不留痕迹的发现远程服务器的各种TCP端口的分配及提供的服务和它们的软件版本!这就能让我们间接的或直观的了解到远程主机所存在的安全问题。
下面是基于TCP扫描,UDP我就不发上来了,下载工程:端口扫描C版
下面是基于TCP扫描,UDP我就不发上来了,下载工程:端口扫描C版
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 | /* * tcp_scan - determine available tcp services, optionally collect banners * and detect telnet options * * Author: Wietse Venema. */ #include <sys types.h=""> #include <sys param.h=""> #include <sys time.h=""> #include <sys socket.h=""> #include <netinet in.h=""> #include <netinet in_systm.h=""> #include <netinet ip.h=""> #include <netinet ip_icmp.h=""> #include <netinet tcp.h=""> #include <arpa telnet.h=""> #include <stdio.h> #include <signal.h> #include <netdb.h> #include <string.h> #include <errno.h> extern int errno ; extern char *optarg; extern int optind; #ifndef __STDC__ extern char * strerror (); #endif #define offsetof(t,m) (size_t)(&(((t *)0)->m)) #ifndef IPPORT_TELNET #define IPPORT_TELNET 23 #endif #ifndef FD_SET #include <sys select.h=""> #endif #ifndef INADDR_ANY #define INADDR_ANY 0xffffffff #endif #include "lib.h" #define BANNER_LENGTH 2048 /* upper bound on banner info */ #define BANNER_TIME 10 /* time for host to send banner */ #define BANNER_IDLE 1 /* delay after last banner info */ #define YES 1 #define NO 0 #define WAIT 1 #define NOWAIT 0 int verbose; /* default silent mode */ int banner_time = BANNER_TIME; /* banner timeout */ int open_file_limit; /* max nr of open files */ int load_limit; /* max nr of open sockets */ struct timeval now; /* banner_info last update time */ fd_set write_socket_mask; /* sockets with connect() in progress */ fd_set read_socket_mask; /* sockets with connect() finished */ int ports_busy; /* number of open sockets */ int ports_done; /* number of finished sockets */ int max_sock; /* max socket file descriptor */ int want_err; /* want good/bad news */ int show_all; /* report all ports */ char *src_port = 0; /* port to send from */ int *socket_to_port; /* socket to port number */ typedef struct { unsigned char *buf; /* banner information or null */ int count; /* amount of banner received sofar */ int flags; /* see below */ struct timeval connect_time; /* when connect() finished */ struct timeval read_time; /* time of last banner update */ } BANNER_INFO; BANNER_INFO *banner_info = 0; #define F_TELNET (1<<0) /* telnet options seen */ int icmp_sock; /* for unreachable reports */ static struct sockaddr_in dst; /* remote endpoint info */ static struct sockaddr_in src; /* local endpoint info */ static char *send_string; /* string to send */ int response_time; /* need some response */ #define NEW(type, count) (type *) mymalloc((count) * sizeof(type)) #define time_since(t) (now.tv_sec - t.tv_sec + 1e-6 * (now.tv_usec - t.tv_usec)) /* main - command-line interface */ main(argc, argv) int argc; char *argv[]; { int c; struct protoent *pe; char **ports; progname = argv[0]; if (geteuid()) error( "This program needs root privileges" ); open_file_limit = open_limit(); load_limit = open_file_limit - 10; while ((c = getopt(argc, argv, "abl:s:t:S:uUvw:" )) != EOF) { switch (c) { case 'a' : show_all = 1; break ; case 'b' : if (banner_info == 0) banner_info = NEW(BANNER_INFO, open_file_limit); break ; case 'l' : if ((load_limit = atoi (optarg)) <= 0) usage( "invalid load limit" ); if (load_limit > open_file_limit - 10) load_limit = open_file_limit - 10; break ; case 's' : send_string = optarg; signal (SIGPIPE, SIG_IGN); break ; case 'S' : src_port = optarg; break ; case 't' : if ((response_time = atoi (optarg)) <= 0) usage( "invalid timeout" ); break ; case 'u' : want_err = EHOSTUNREACH; break ; case 'U' : want_err = ~EHOSTUNREACH; break ; case 'v' : verbose = 1; break ; case 'w' : if ((banner_time = atoi (optarg)) <= 0) usage( "invalid timeout" ); break ; default : usage(( char *) 0); break ; } } argc -= (optind - 1); argv += (optind - 1); if (argc < 3) usage( "missing host or service argument" ); socket_to_port = NEW( int , open_file_limit); FD_ZERO(&write_socket_mask); FD_ZERO(&read_socket_mask); ports_busy = 0; /* * Allocate the socket to read ICMP replies. */ if ((pe = getprotobyname( "icmp" )) == 0) error( "icmp: unknown protocol" ); if ((icmp_sock = socket(AF_INET, SOCK_RAW, pe->p_proto)) < 0) error( "icmp socket: %m" ); FD_SET(icmp_sock, &read_socket_mask); /* * Scan the ports. */ memset (( char *) &dst, 0, sizeof (dst)); dst.sin_addr = find_addr(argv[1]); dst.sin_family = AF_INET; if (src_port) { memset (( char *) &src, 0, sizeof (src)); src.sin_addr.s_addr = INADDR_ANY; src.sin_port = find_port(src_port, "tcp" ); src.sin_family = AF_INET; } if (response_time > 0) alarm(response_time); for (ports = argv + 2; *ports; ports++) scan_ports(*ports); while (ports_busy > 0) monitor_ports(WAIT); return (0); } /* usage - explain command syntax */ usage(why) char *why; { if (why) remark(why); error( "usage: %s [-abuU] [-l load] [-s string] [-S src_port] [-w time] host ports..." , progname); } /* scan_ports - scan ranges of ports */ scan_ports(service) char *service; { char *cp; int min_port; int max_port; int port; int sock; /* * Translate service argument to range of port numbers. */ if ((cp = strchr (service, '-' )) != 0) { *cp++ = 0; min_port = (service[0] ? ntohs(find_port(service, "tcp" )) : 1); max_port = (cp[0] ? ntohs(find_port(cp, "tcp" )) : 65535); } else { min_port = max_port = ntohs(find_port(service, "tcp" )); } /* * Iterate over each port in the given range. Try to keep as many sockets * open at the same time as possible. Gradually increase the number of * probes so that they will be spread in time. */ for (port = min_port; port <= max_port; port++) { if (verbose) remark( "connecting to port %d" , port); dst.sin_port = htons(port); while ((sock = socket(dst.sin_family, SOCK_STREAM, 0)) < 0) { remark( "socket: %m" ); monitor_ports(WAIT); } if (src_port && bind(sock, ( struct sockaddr *) & src, sizeof (src)) < 0) error( "bind port %s: %m" , src_port); add_socket(sock, port); non_blocking(sock, YES); if (connect(sock, ( struct sockaddr *) & dst, sizeof (dst)) < 0 && errno != EINPROGRESS) { if ( errno == EADDRINUSE) error( "connect: %m" ); report_and_drop_socket(sock, errno ); continue ; } if (ports_busy < load_limit && ports_busy < ports_done) { monitor_ports(NOWAIT); } else { while (ports_busy >= load_limit || ports_busy >= ports_done) monitor_ports(WAIT); } } } /* monitor_ports - watch for socket activity */ monitor_ports(wait) int wait; { fd_set read_mask; fd_set write_mask; static struct timeval waitsome = {1, 1,}; static struct timeval waitnot = {0, 0,}; int sock; char ch; if (banner_info == 0) { /* * When a connect() completes, report the socket and get rid of it. */ write_mask = write_socket_mask; read_mask = read_socket_mask; if (select(max_sock + 1, &read_mask, &write_mask, (fd_set *) 0, wait ? ( struct timeval *) 0 : &waitnot) < 0) error( "select: %m" ); if (FD_ISSET(icmp_sock, &read_mask)) receive_icmp(icmp_sock); for (sock = 0; ports_busy > 0 && sock <= max_sock; sock++) { if (FD_ISSET(sock, &write_mask)) { if (read(sock, &ch, 1) < 0 && errno != EWOULDBLOCK && errno != EAGAIN) { if ( errno == EADDRINUSE) error( "connect: %m" ); report_and_drop_socket(sock, errno ); } else { report_and_drop_socket(sock, 0); } } } } else { /* * When a connect() completes, try to receive some data within * banner_time seconds. Assume we have received all banner data when * a socket stops sending for BANNER_IDLE seconds. */ write_mask = write_socket_mask; read_mask = read_socket_mask; if (select(max_sock + 1, &read_mask, &write_mask, (fd_set *) 0, wait ? &waitsome : &waitnot) < 0) error( "select: %m" ); if (FD_ISSET(icmp_sock, &read_mask)) receive_icmp(icmp_sock); gettimeofday(&now, ( struct timezone *) 0); for (sock = 0; ports_busy > 0 && sock <= max_sock; sock++) { if (sock == icmp_sock) continue ; if (FD_ISSET(sock, &write_mask)) { FD_CLR(sock, &write_socket_mask); FD_SET(sock, &read_socket_mask); banner_info[sock].connect_time = now; if (send_string) do_send_string(sock); } else if (FD_ISSET(sock, &read_mask)) { switch (read_socket(sock)) { case -1: if ( errno != EWOULDBLOCK && errno != EAGAIN) report_and_drop_socket(sock, errno ); break ; case 0: report_and_drop_socket(sock, 0); break ; } } else if (FD_ISSET(sock, &read_socket_mask)) { if (time_since_connect(sock) > banner_time || time_since_read(sock) > BANNER_IDLE) report_and_drop_socket(sock, 0); } } } } /* read_socket - read data from server */ read_socket(sock) int sock; { BANNER_INFO *bp = banner_info + sock; unsigned char *cp; int len; int count; if (bp->buf == 0) bp->buf = (unsigned char *) mymalloc(BANNER_LENGTH); cp = bp->buf + bp->count; len = BANNER_LENGTH - bp->count; if (len == 0) return (0); bp->read_time = now; /* * Process banners with one-character reads so that we can detect telnet * options. */ if ((count = read(sock, cp, 1)) == 1) { if (cp[0] == IAC) { if ((count = read(sock, cp + 1, 2)) == 2) { if (cp[1] == WILL || cp[1] == WONT) { cp[1] = DONT; bp->flags |= F_TELNET; write(sock, cp, 3); } else if (cp[1] == DO || cp[1] == DONT) { cp[1] = WONT; bp->flags |= F_TELNET; write(sock, cp, 3); } } } else { /* cp[0] != IAC */ bp->count++; } } return (count); } /* report_and_drop_socket - report what we know about this service */ report_and_drop_socket(sock, err) int sock; int err; { alarm(0); if (show_all || want_err == err || (want_err < 0 && want_err != ~err)) { struct servent *sp; int port = socket_to_port[sock]; printf ( "%d:%s:" , port, (sp = getservbyport(htons(port), "tcp" )) != 0 ? sp->s_name : "UNKNOWN" ); if (banner_info) { BANNER_INFO *bp = banner_info + sock; if (bp->flags & F_TELNET) putchar ( 't' ); putchar ( ':' ); if (bp->count > 0) print_data(stdout, bp->buf, bp->count); } if (err && show_all) printf ( "%s" , strerror (err)); printf ( "\n" ); fflush (stdout); } drop_socket(sock); } /* add_socket - say this socket is being connected */ add_socket(sock, port) int sock; int port; { BANNER_INFO *bp; socket_to_port[sock] = port; if (banner_info) { bp = banner_info + sock; bp->count = 0; bp->buf = 0; bp->flags = 0; } FD_SET(sock, &write_socket_mask); if (sock > max_sock) max_sock = sock; ports_busy++; } /* drop_socket - release socket resources */ drop_socket(sock) int sock; { BANNER_INFO *bp; if (banner_info && (bp = banner_info + sock)->buf) free (( char *) bp->buf); close(sock); FD_CLR(sock, &read_socket_mask); FD_CLR(sock, &write_socket_mask); ports_busy--; ports_done++; } /* time_since_read - how long since read() completed? */ time_since_read(sock) int sock; { BANNER_INFO *bp = banner_info + sock; return (bp->count == 0 ? 0 : time_since(bp->read_time)); } /* time_since_connect - how long since connect() completed? */ time_since_connect(sock) int sock; { BANNER_INFO *bp = banner_info + sock; return (time_since(bp->connect_time)); } /* receive_icmp - receive and decode ICMP message */ receive_icmp(sock) int sock; { union { char chars[BUFSIZ]; struct ip ip; } buf; int data_len; int hdr_len; struct ip *ip; struct icmp *icmp; struct tcphdr *tcp; int port; if ((data_len = recv(sock, ( char *) &buf, sizeof (buf), 0)) < 0) { error( "error: recv: %m" ); return ; } /* * Extract the IP header. */ ip = &buf.ip; if (ip->ip_p != IPPROTO_ICMP) { error( "error: not ICMP proto (%d)" , ip->ip_p); return ; } /* * Extract the IP payload. */ hdr_len = ip->ip_hl << 2; if (data_len - hdr_len < ICMP_MINLEN) { remark( "short ICMP packet (%d bytes)" , data_len); return ; } icmp = ( struct icmp *) (( char *) ip + hdr_len); data_len -= hdr_len; if (icmp->icmp_type != ICMP_UNREACH) return ; /* * Extract the offending IP packet header. */ if (data_len < offsetof( struct icmp, icmp_ip) + sizeof (icmp->icmp_ip)) { remark( "short IP header in ICMP" ); return ; } ip = &(icmp->icmp_ip); if (ip->ip_p != IPPROTO_TCP) return ; if (ip->ip_dst.s_addr != dst.sin_addr.s_addr) return ; /* * Extract the offending TCP packet header. */ hdr_len = ip->ip_hl << 2; tcp = ( struct tcphdr *) (( char *) ip + hdr_len); data_len -= hdr_len; if (data_len < offsetof( struct tcphdr, th_dport) + sizeof (tcp->th_dport)) { remark( "short TCP header in ICMP" ); return ; } /* * Process ICMP subcodes. */ switch (icmp->icmp_code) { case ICMP_UNREACH_NET: case ICMP_UNREACH_PROTOCOL: /* error("error: network or protocol unreachable"); */ /* NOTREACHED */ case ICMP_UNREACH_PORT: case ICMP_UNREACH_HOST: port = ntohs(tcp->th_dport); for (sock = 0; sock < open_file_limit; sock++) if (socket_to_port[sock] == port) { report_and_drop_socket(sock, EHOSTUNREACH); return ; } break ; } } /* do_send_string - send the send string */ do_send_string(sock) int sock; { char buf[BUFSIZ]; char *cp = buf; char ch; int c; int i; char *s = send_string; while (*s && cp < buf + sizeof (buf) - 1) { /* don't overflow the buffer */ if (*s != '\\' ) { /* ordinary character */ *cp++ = *s++; } else if ( isdigit (*++s) && *s < '8' ) { /* \nnn octal code */ sscanf (s, "%3o" , &c); *cp++ = c; for (i = 0; i < 3 && isdigit (*s) && *s < '8' ; i++) s++; } else if ((ch = *s++) == 0) { /* at string terminator */ break ; } else if (ch == 'b' ) { /* \b becomes backspace */ *cp++ = '\b' ; } else if (ch == 'f' ) { /* \f becomes formfeed */ *cp++ = '\f' ; } else if (ch == 'n' ) { /* \n becomes newline */ *cp++ = '\n' ; } else if (ch == 'r' ) { /* \r becomes carriage ret */ *cp++ = '\r' ; } else if (ch == 's' ) { /* \s becomes blank */ *cp++ = ' ' ; } else if (ch == 't' ) { /* \t becomes tab */ *cp++ = '\t' ; } else { /* \any becomes any */ *cp++ = ch; } } write(sock, buf, cp - buf); } </sys></ errno .h></string.h></netdb.h></ signal .h></stdio.h></arpa></netinet></netinet></netinet></netinet></netinet></sys></sys></sys></sys> |
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