Nmap备忘单:从探索到漏洞利用分析第二部分2

  proxy->max_groupsz = (o.max_parallelism)? o.max_parallelism : 100;

  proxy->min_groupsz = (o.min_parallelism)? o.min_parallelism : 4;

  proxy->max_senddelay = 100000;

  Strncpy(name, proxyName, sizeof(name));

  q = strchr(name, ‘:’);

  if (q) {

  *q++ = ”;

  proxy->probe_port = strtoul(q, &endptr, 10);

  if (*q==0 || !endptr || *endptr != ” || !proxy->probe_port) {

  fatal(“Invalid port number given in IP ID zombie specification: %s”, proxyName);

  }

  } else {

  if (ports->syn_ping_count > 0) {

  proxy->probe_port = ports->syn_ping_ports[0];

  } else if (ports->ack_ping_count > 0) {

  proxy->probe_port = ports->ack_ping_ports[0];

  } else {

  u16 *ports;

  int count;

  getpts_simple(DEFAULT_TCP_PROBE_PORT_SPEC, SCAN_TCP_PORT, &ports, &count);

  assert(count > 0);

  proxy->probe_port = ports[0];

  free(ports);

  }

  }

  proxy->host.setHostName(name);

  if (resolve(name, 0, 0, &ss, &sslen, o.pf()) == 0) {

  fatal(“Could not resolve idle scan zombie host: %s”, name);

  }

  proxy->host.setTargetSockAddr(&ss, sslen);

  /* Lets figure out the appropriate source address to use when sending

  the pr0bez */

  proxy->host.TargetSockAddr(&ss, &sslen);

  if (!NMAP_route_dst(&ss, &rnfo))

  fatal(“Unable to find appropriate source address and device interface to use when sending packets to %s”, proxyName);

  if (o.spoofsource) {

  o.SourceSockAddr(&ss, &sslen);

  proxy->host.setSourceSockAddr(&ss, sslen);

  proxy->host.setDeviceNames(o.device, o.device);

  } else {

  proxy->host.setDeviceNames(rnfo.ii.devname, rnfo.ii.devfullname);

  proxy->host.setSourceSockAddr(&rnfo.srcaddr, sizeof(rnfo.srcaddr));

  }

  if (rnfo.direct_connect) {

  proxy->host.setDirectlyConnected(true);

  } else {

  proxy->host.setDirectlyConnected(false);

  proxy->host.setNextHop(&rnfo.nexthop,

  sizeof(rnfo.nexthop));

  }

  proxy->host.setIfType(rnfo.ii.device_type);

  if (rnfo.ii.device_type == devt_ethernet)

  proxy->host.setSrcMACAddress(rnfo.ii.mac);

  /* Now lets send some probes to check IP ID algorithm … */

  /* First we need a raw socket … */

  if ((o.sendpref & PACKET_SEND_ETH) && proxy->host.ifType() == devt_ethernet) {

  if (!setTargetNextHopMAC(&proxy->host))

  fatal(“%s: Failed to determine dst MAC address for Idle proxy”,

  __func__);

  memcpy(proxy->eth.srcmac, proxy->host.SrcMACAddress(), 6);

  memcpy(proxy->eth.dstmac, proxy->host.NextHopMACAddress(), 6);

  proxy->eth.ethsd = eth_open_cached(proxy->host.deviceName());

  if (proxy->eth.ethsd == NULL)

  fatal(“%s: Failed to open ethernet device (%s)”, __func__, proxy->host.deviceName());

  proxy->rawsd = -1;

  proxy->ethptr = &proxy->eth;

  } else {

  #ifdef WIN32

  win32_fatal_raw_sockets(proxy->host.deviceName());

  #endif

  if ((proxy->rawsd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0 ) pfatal(“socket troubles in %s”, __func__); unblock_socket(proxy->rawsd);

  broadcast_socket(proxy->rawsd);

  #ifndef WIN32

  sethdrinclude(proxy->rawsd);

  #endif

  proxy->eth.ethsd = NULL;

  proxy->ethptr = NULL;

  }

  /* Now for the pcap opening nonsense … */

  /* Note that the snaplen is 152 = 64 byte max IPhdr + 24 byte max link_layer

  * header + 64 byte max TCP header. */

  if((proxy->pd=my_pcap_open_live(proxy->host.deviceName(), 152, (o.spoofsource)? 1 : 0, 50))==NULL)

  fatal(“%s”, PCAP_OPEN_ERRMSG);

  p = strdup(proxy->host.targetipstr());

  q = strdup(inet_ntoa(proxy->host.v4source()));

  Snprintf(filter, sizeof(filter), “tcp and src host %s and dst host %s and src port %hu”, p, q, proxy->probe_port);

  free(p);

  free(q);

  set_pcap_filter(proxy->host.deviceFullName(), proxy->pd, filter);

  if (o.debugging)

  log_write(LOG_STDOUT, “Packet capture filter (device %s): %s/n”, proxy->host.deviceFullName(), filter);

  /* Windows nonsense — I am not sure why this is needed, but I should

  get rid of it at sometime */

  sequence_base = get_random_u32();

  /* Yahoo! It is finally time to send our pr0beZ! */

  while(probes_sent < NUM_IPID_PROBES) { if (o.scan_delay) enforce_scan_delay(NULL); else if (probes_sent) usleep(30000); /* TH_SYN|TH_ACK is what the proxy will really be receiving from the target, and is more likely to get through firewalls. But TH_SYN allows us to get a nonzero ACK back so we can associate a response with the exact request for timing purposes. So I think I’ll use TH_SYN, although it is a tough call. */ /* We can’t use decoys ’cause that would screw up the IP IDs */ send_tcp_raw(proxy->rawsd, proxy->ethptr,

  proxy->host.v4sourceip(), proxy->host.v4hostip(),

  o.ttl, false,

  o.ipoptions, o.ipoptionslen,

  o.magic_port + probes_sent + 1, proxy->probe_port,

  sequence_base + probes_sent + 1, ack, 0, TH_SYN|TH_ACK, 0, 0,

  (u8 *) “/x02/x04/x05/xb4”,4,

  NULL, 0);

  gettimeofday(&probe_send_times[probes_sent], NULL);

  probes_sent++;

  /* Time to collect any replies */

  while(probes_returned < probes_sent && !timedout) { to_usec = (probes_sent == NUM_IPID_PROBES)? hardtimeout : 1000; ip = (struct ip *) readipv4_pcap(proxy->pd, &bytes, to_usec, &rcvdtime, NULL, true);

  gettimeofday(&tmptv, NULL);

  if (!ip) {

  if (probes_sent < NUM_IPID_PROBES) break; if (TIMEVAL_SUBTRACT(tmptv, probe_send_times[probes_sent – 1]) >= hardtimeout) {

  timedout = 1;

  }

  continue;

  } else if (TIMEVAL_SUBTRACT(tmptv, probe_send_times[probes_sent – 1]) >=

  hardtimeout) {

  timedout = 1;

  }

  if (lastipid != 0 && ip->ip_id == lastipid) {

  continue; /* probably a duplicate */

  }

  lastipid = ip->ip_id;

  if (bytes < ( 4 * ip->ip_hl) + 14U)

  continue;

  if (ip->ip_p == IPPROTO_TCP) {

  tcp = ((struct tcp_hdr *) (((char *) ip) + 4 * ip->ip_hl));

  if (ntohs(tcp->th_dport) < (o.magic_port+1) || ntohs(tcp->th_dport) – o.magic_port > NUM_IPID_PROBES || ntohs(tcp->th_sport) != proxy->probe_port || ((tcp->th_flags & TH_RST) == 0)) {

  if (o.debugging > 1) error(“Received unexpected response packet from %s during initial IP ID zombie testing”, inet_ntoa(ip->ip_src));

  continue;

  }

  seq_response_num = probes_returned;

  /* The stuff below only works when we send SYN packets instead of

  SYN|ACK, but then are slightly less stealthy and have less chance

  of sneaking through the firewall. Plus SYN|ACK is what they will

  be receiving back from the target */

  probes_returned++;

  ipids[seq_response_num] = (u16) ntohs(ip->ip_id);

  probe_returned[seq_response_num] = 1;

  adjust_timeouts2(&probe_send_times[seq_response_num], &rcvdtime, &(proxy->host.to));

  }

  }

  }

  /* Yeah! We’re done sending/receiving probes … now lets ensure all of our responses are adjacent in the array */

  for(i=0,probes_returned=0; i < NUM_IPID_PROBES; i++) { if (probe_returned[i]) { if (i > probes_returned)

  ipids[probes_returned] = ipids[i];

  probes_returned++;

  }

  }

  if (probes_returned == 0)

  fatal(“Idle scan zombie %s (%s) port %hu cannot be used because it has not returned any of our probes — perhaps it is down or firewalled.”,

  proxy->host.HostName(), proxy->host.targetipstr(),

  proxy->probe_port);

  proxy->seqclass = get_ipid_sequence(probes_returned, ipids, 0);

  switch(proxy->seqclass) {

  case IPID_SEQ_INCR:

  case IPID_SEQ_BROKEN_INCR:

  log_write(LOG_PLAIN, “Idle scan using zombie %s (%s:%hu); Class: %s/n”, proxy->host.HostName(), proxy->host.targetipstr(), proxy->probe_port, ipidclass2ascii(proxy->seqclass));

  break;

  default:

  fatal(“Idle scan zombie %s (%s) port %hu cannot be used because IP ID sequencability class is: %s. Try another proxy.”, proxy->host.HostName(), proxy->host.targetipstr(), proxy->probe_port, ipidclass2ascii(proxy->seqclass));

  }

  proxy->latestid = ipids[probes_returned – 1];

  proxy->current_groupsz = MIN(proxy->max_groupsz, 30);

  if (probes_returned < NUM_IPID_PROBES) { /* Yikes! We’re already losing packets … clamp down a bit … */ if (o.debugging) error(“Idle scan initial zombie qualification test: %d probes sent, only %d returned”, NUM_IPID_PROBES, probes_returned); proxy->current_groupsz = MIN(12, proxy->max_groupsz);

  proxy->current_groupsz = MAX(proxy->current_groupsz, proxy->min_groupsz);

  proxy->senddelay += 5000;

  }

  /* OK, through experimentation I have found that some hosts (*cough*

  Solaris) APPEAR to use simple IP ID incrementing, but in reality they

  assign a new IP ID base to each host which connects with them. This

  is actually a good idea on several fronts, but it totally

  frustrates our efforts (which rely on side-channel IP ID info

  leaking to different hosts). The good news is that we can easily

  detect the problem by sending some spoofed packets “from” the first

  target to the zombie and then probing to verify that the proxy IP ID

  changed. This will also catch the case where the NMAP user is

  behind an egress filter or other measure that prevents this sort of

  sp00fery */

  if (first_target) {

  for (probes_sent = 0; probes_sent < 4; probes_sent++) { if (probes_sent) usleep(50000); send_tcp_raw(proxy->rawsd, proxy->ethptr,

  first_target, proxy->host.v4hostip(),

  o.ttl, false,

  o.ipoptions, o.ipoptionslen,

  o.magic_port, proxy->probe_port,

  sequence_base + probes_sent + 1, ack, 0, TH_SYN|TH_ACK, 0, 0,

  (u8 *) “/x02/x04/x05/xb4”,

  4, NULL, 0);

  }

  /* Sleep a little while to give packets time to reach their destination */

  usleep(300000);

  newipid = ipid_proxy_probe(proxy, NULL, NULL);

  if (newipid == -1)

  newipid = ipid_proxy_probe(proxy, NULL, NULL); /* OK, we’ll give it one more try */

  if (newipid < 0) fatal(“Your IP ID Zombie (%s; %s) is behaving strangely — suddenly cannot obtain IP ID”, proxy->host.HostName(), proxy->host.targetipstr());

  distance = ipid_distance(proxy->seqclass, proxy->latestid, newipid);

  if (distance <= 0) { fatal(“Your IP ID Zombie (%s; %s) is behaving strangely — suddenly cannot obtain valid IP ID distance.”, proxy->host.HostName(), proxy->host.targetipstr());

  } else if (distance == 1) {

  fatal(“Even though your Zombie (%s; %s) appears to be vulnerable to IP ID sequence prediction (class: %s), our attempts have failed. This generally means that either the zombie uses a separate IP ID base for each host (like Solaris), or because you cannot spoof IP packets (perhaps your ISP has enabled egress filtering to prevent IP spoofing), or maybe the target network recognizes the packet source as bogus and drops them”, proxy->host.HostName(), proxy->host.targetipstr(), ipidclass2ascii(proxy->seqclass));

  }

  if (o.debugging && distance != 5) {

  error(“WARNING: IP ID spoofing test sent 4 packets and expected a distance of 5, but instead got %d”, distance);

  }

  proxy->latestid = newipid;

  }

  }

  /* Adjust timing parameters up or down given that an idle scan found a

  count of ‘testcount’ while the ‘realcount’ is as given. If the

  testcount was correct, timing is made more aggressive, while it is

  slowed down in the case of an error */

  static void adjust_idle_timing(struct idle_proxy_info *proxy,

  Target *target, int testcount,

  int realcount) {

  static int notidlewarning = 0;

  if (o.debugging > 1)

  log_write(LOG_STDOUT,

  ”%s: tested/true %d/%d — old grpsz/delay: %f/%d “,

  __func__, testcount, realcount, proxy->current_groupsz, proxy->senddelay);

  else if (o.debugging && testcount != realcount) {

  error(“%s: testcount: %d realcount: %d — old grpsz/delay: %f/%d”, __func__, testcount, realcount, proxy->current_groupsz, proxy->senddelay);

  }

  if (testcount < realcount) { /* We must have missed a port — our probe could have been dropped, the response to proxy could have been dropped, or we didn’t wait long enough before probing the proxy IP ID. The third case is covered elsewhere in the scan, so we worry most about the first two. The solution is to decrease our group size and add a sending delay */ /* packets could be dropped because too many were sent at once */ proxy->current_groupsz = MAX(proxy->min_groupsz, proxy->current_groupsz * 0.8);

  proxy->senddelay += 10000;

  proxy->senddelay = MIN(proxy->max_senddelay, proxy->senddelay);

  /* No group size should be greater than .5s of send delays */

  proxy->current_groupsz = MAX(proxy->min_groupsz, MIN(proxy->current_groupsz, 500000 / (proxy->senddelay + 1)));

  } else if (testcount > realcount) {

  /* Perhaps the proxy host is not really idle … */

  /* I guess all I can do is decrease the group size, so that if the proxy is not really idle, at least we may be able to scan chunks more quickly in between outside packets */

  proxy->current_groupsz = MAX(proxy->min_groupsz, proxy->current_groupsz * 0.8);

  if (!notidlewarning && o.verbose) {

  notidlewarning = 1;

  error(“WARNING: idle scan has erroneously detected phantom ports — is the proxy %s (%s) really idle?”, proxy->host.HostName(), proxy->host.targetipstr());

  }

  } else {

  /* W00p We got a perfect match. That means we get a slight increase

  in allowed group size and we can lightly decrease the senddelay */

  proxy->senddelay = (int) (proxy->senddelay * 0.9);

  if (proxy->senddelay < 500) proxy->senddelay = 0;

  proxy->current_groupsz = MIN(proxy->current_groupsz * 1.1, 500000 / (proxy->senddelay + 1));

  proxy->current_groupsz = MIN(proxy->max_groupsz, proxy->current_groupsz);

  }

  if (o.debugging > 1)

  log_write(LOG_STDOUT, “-> %f/%d/n”, proxy->current_groupsz, proxy->senddelay);

  }

  /* OK, now this is the hardcore idle scan function which actually does

  the testing (most of the other cruft in this file is just

  coordination, preparation, etc). This function simply uses the

  idle scan technique to try and count the number of open ports in the

  given port array. The sent_time and rcv_time are filled in with

  the times that the probe packet & response were sent/received.

  They can be NULL if you don’t want to use them. The purpose is for

  timing adjustments if the numbers turn out to be accurate. */

  static int idlescan_countopen2(struct idle_proxy_info *proxy,

  Target *target, u16 *ports, int numports,

  struct timeval *sent_time, struct timeval *rcv_time)

  {

  #if 0 /* Testing code */

  int i;

  for(i=0; i < numports; i++) if (ports[i] == 22) return 1; return 0; #endif int openports; int tries; int proxyprobes_sent = 0; /* diff. from tries ’cause sometimes we skip tries */ int proxyprobes_rcvd = 0; /* To determine if packets were dr0pped */ int sent, rcvd; int ipid_dist; struct timeval start, end, latestchange, now; struct timeval probe_times[4]; int pr0be; static u32 seq = 0; int newipid = 0; int sleeptime; int lasttry = 0; int dotry3 = 0; struct eth_nfo eth; if (seq == 0) seq = get_random_u32(); memset(&end, 0, sizeof(end)); memset(&latestchange, 0, sizeof(latestchange)); gettimeofday(&start, NULL); if (sent_time) memset(sent_time, 0, sizeof(*sent_time)); if (rcv_time) memset(rcv_time, 0, sizeof(*rcv_time)); if (proxy->rawsd < 0) { if (!setTargetNextHopMAC(target)) fatal(“%s: Failed to determine dst MAC address for Idle proxy”, __func__); memcpy(eth.srcmac, target->SrcMACAddress(), 6);

  memcpy(eth.dstmac, target->NextHopMACAddress(), 6);

  eth.ethsd = eth_open_cached(target->deviceName());

  if (eth.ethsd == NULL)

  fatal(“%s: Failed to open ethernet device (%s)”, __func__, target->deviceName());

  } else eth.ethsd = NULL;

  /* I start by sending out the SYN pr0bez */

  for(pr0be = 0; pr0be < numports; pr0be++) { if (o.scan_delay) enforce_scan_delay(NULL); else if (proxy->senddelay && pr0be > 0) usleep(proxy->senddelay);

  /* Maybe I should involve decoys in the picture at some point —

  but doing it the straightforward way (using the same decoys as

  we use in probing the proxy box is risky. I’ll have to think

  about this more. */

  send_tcp_raw(proxy->rawsd, eth.ethsd? e : NULL,

  proxy->host.v4hostip(), target->v4hostip(),

  o.ttl, false,

  o.ipoptions, o.ipoptionslen,

  proxy->probe_port, ports[pr0be], seq, 0, 0, TH_SYN, 0, 0,

  (u8 *) “/x02/x04/x05/xb4”, 4,

  o.extra_payload, o.extra_payload_length);

  }

  gettimeofday(&end, NULL);

  openports = -1;

  tries = 0;

  TIMEVAL_MSEC_ADD(probe_times[0], start, MAX(50, (target->to.srtt * 3/4) / 1000));

  TIMEVAL_MSEC_ADD(probe_times[1], start, target->to.srtt / 1000 );

  TIMEVAL_MSEC_ADD(probe_times[2], end, MAX(75, (2 * target->to.srtt +

  target->to.rttvar) / 1000));

  TIMEVAL_MSEC_ADD(probe_times[3], end, MIN(4000, (2 * target->to.srtt +

  (target->to.rttvar << 2 )) / 1000)); do { if (tries == 2) dotry3 = (get_random_u8() > 200);

  if (tries == 3 && !dotry3)

  break; /* We usually want to skip the long-wait test */

  if (tries == 3 || (tries == 2 && !dotry3))

  lasttry = 1;

  gettimeofday(&now, NULL);

  sleeptime = TIMEVAL_SUBTRACT(probe_times[tries], now);

  if (!lasttry && proxyprobes_sent > 0 && sleeptime < 50000)

  continue; /* No point going again so soon */

  if (tries == 0 && sleeptime < 500) sleeptime = 500; if (o.debugging > 1) error(“In preparation for idle scan probe try #%d, sleeping for %d usecs”, tries, sleeptime);

  if (sleeptime > 0)

  usleep(sleeptime);

  newipid = ipid_proxy_probe(proxy, &sent, &rcvd);

  proxyprobes_sent += sent;

  proxyprobes_rcvd += rcvd;

  if (newipid > 0) {

  ipid_dist = ipid_distance(proxy->seqclass, proxy->latestid, newipid);

  /* I used to only do this if ipid_sit >= proxyprobes_sent, but I’d

  rather have a negative number in that case. */

  if (ipid_dist < proxyprobes_sent) { if (o.debugging) error(“%s: Must have lost a sent packet because ipid_dist is %d while proxyprobes_sent is %d.”, __func__, ipid_dist, proxyprobes_sent); /* I no longer whack timing here … done at bottom. */ } ipid_dist -= proxyprobes_sent; if (ipid_dist > openports) {

  openports = ipid_dist;

  gettimeofday(&latestchange, NULL);

  } else if (ipid_dist < openports && ipid_dist >= 0) {

  /* Uh-oh. Perhaps I dropped a packet this time */

  if (o.debugging > 1) {

  error(“%s: Counted %d open ports in try #%d, but counted %d earlier … probably a proxy_probe problem”, __func__, ipid_dist, tries, openports);

  }

  /* I no longer whack timing here … done at bottom. */

  }

  }

  if (openports > numports || (numports <= 2 && (openports == numports)))

  break;

  } while(tries++ < 3); if (proxyprobes_sent > proxyprobes_rcvd) {

  /* Uh-oh. It looks like we lost at least one proxy probe packet */

  if (o.debugging) {

  error(“%s: Sent %d probes; only %d responses. Slowing scan.”, __func__, proxyprobes_sent, proxyprobes_rcvd);

  }

  proxy->senddelay += 5000;

  proxy->senddelay = MIN(proxy->max_senddelay, proxy->senddelay);

  /* No group size should be greater than .5s of send delays */

  proxy->current_groupsz = MAX(proxy->min_groupsz, MIN(proxy->current_groupsz, 500000 / (proxy->senddelay+1)));

  } else {

  /* Yeah, we got as many responses as we sent probes. This calls for a

  very light timing acceleration … */

  proxy->senddelay = (int) (proxy->senddelay * 0.95);

  if (proxy->senddelay < 500) proxy->senddelay = 0;

  proxy->current_groupsz = MAX(proxy->min_groupsz, MIN(proxy->current_groupsz, 500000 / (proxy->senddelay+1)));

  }

  if ((openports > 0) && (openports <= numports)) { /* Yeah, we found open ports… lets adjust the timing … */ if (o.debugging > 2) error(“%s: found %d open ports (out of %d) in %lu usecs”, __func__, openports, numports, (unsigned long) TIMEVAL_SUBTRACT(latestchange, start));

  if (sent_time) *sent_time = start;

  if (rcv_time) *rcv_time = latestchange;

  }

  if (newipid > 0) proxy->latestid = newipid;

  if (eth.ethsd) { eth.ethsd = NULL; } /* don’t need to close it due to caching */

  return openports;

  }

  /* The job of this function is to use the idle scan technique to count

  the number of open ports in the given list. Under the covers, this

  function just farms out the hard work to another function. */

  static int idlescan_countopen(struct idle_proxy_info *proxy,

  Target *target, u16 *ports, int numports,

  struct timeval *sent_time, struct timeval *rcv_time) {

  int tries = 0;

  int openports;

  do {

  openports = idlescan_countopen2(proxy, target, ports, numports, sent_time,

  rcv_time);

  tries++;

  if (tries == 6 || (openports >= 0 && openports <= numports)) break; if (o.debugging) { error(“%s: In try #%d, counted %d open ports out of %d. Retrying”, __func__, tries, openports, numports); } /* Sleep for a little while — maybe proxy host had brief birst of traffic or similar problem */ sleep(tries * tries); if (tries == 5) sleep(45); /* We’re gonna give up if this fails, so we will be a bit patient */ /* Since the host may have received packets while we were sleeping, lets update our proxy IP ID counter */ proxy->latestid = ipid_proxy_probe(proxy, NULL, NULL);

  } while(1);

  if (openports < 0 || openports > numports ) {

  /* Oh f*ck!!!! */

  fatal(“Idle scan is unable to obtain meaningful results from proxy %s (%s). I’m sorry it didn’t work out.”, proxy->host.HostName(),

  proxy->host.targetipstr());

  }

  if (o.debugging > 2) error(“%s: %d ports found open out of %d, starting with %hu”, __func__, openports, numports, ports[0]);

  return openports;

  }

  /* Recursively idle scans scans a group of ports using a depth-first

  divide-and-conquer strategy to find the open one(s). */

  static int idle_treescan(struct idle_proxy_info *proxy, Target *target,

  u16 *ports, int numports, int expectedopen) {

  int firstHalfSz = (numports + 1)/2;

  int secondHalfSz = numports – firstHalfSz;

  int flatcount1, flatcount2;

  int deepcount1 = -1, deepcount2 = -1;

  struct timeval sentTime1, rcvTime1, sentTime2, rcvTime2;

  int retrycount = -1, retry2 = -1;

  int totalfound = 0;

  /* Scan the first half of the range */

  if (o.debugging > 1) {

  error(“%s: Called against %s with %d ports, starting with %hu. expectedopen: %d”, __func__, target->targetipstr(), numports, ports[0], expectedopen);

  error(“IDLE SCAN TIMING: grpsz: %.3f delay: %d srtt: %d rttvar: %d”,

  proxy->current_groupsz, proxy->senddelay, target->to.srtt,

  target->to.rttvar);

  }

  flatcount1 = idlescan_countopen(proxy, target, ports, firstHalfSz,

  &sentTime1, &rcvTime1);

  if (firstHalfSz > 1 && flatcount1 > 0) {

  /* A port appears open! We dig down deeper to find it … */

  deepcount1 = idle_treescan(proxy, target, ports, firstHalfSz, flatcount1);

  /* Now we assume deepcount1 is right, and adjust timing if flatcount1 was

  wrong. */

  adjust_idle_timing(proxy, target, flatcount1, deepcount1);

  }

  /* I guess we had better do the second half too … */

  flatcount2 = idlescan_countopen(proxy, target, ports + firstHalfSz,

  secondHalfSz, &sentTime2, &rcvTime2);

  if ((secondHalfSz) > 1 && flatcount2 > 0) {

  /* A port appears open! We dig down deeper to find it … */

  deepcount2 = idle_treescan(proxy, target, ports + firstHalfSz,

  secondHalfSz, flatcount2);

  /* Now we assume deepcount1 is right, and adjust timing if flatcount1 was

  wrong */

  adjust_idle_timing(proxy, target, flatcount2, deepcount2);

  }

  totalfound = (deepcount1 == -1)? flatcount1 : deepcount1;

  totalfound += (deepcount2 == -1)? flatcount2 : deepcount2;

  if ((flatcount1 + flatcount2 == totalfound) &&

  (expectedopen == totalfound || expectedopen == -1)) {

  if (flatcount1 > 0) {

  if (o.debugging > 1) {

  error(“Adjusting timing — idlescan_countopen correctly found %d open ports (out of %d, starting with %hu)”, flatcount1, firstHalfSz, ports[0]);

  }

  adjust_timeouts2(&sentTime1, &rcvTime1, &(target->to));

  }

  if (flatcount2 > 0) {

  if (o.debugging > 2) {

  error(“Adjusting timing — idlescan_countopen correctly found %d open ports (out of %d, starting with %hu)”, flatcount2, secondHalfSz,

  ports[firstHalfSz]);

  }

  adjust_timeouts2(&sentTime2, &rcvTime2, &(target->to));

  }

  }

  if (totalfound != expectedopen) {

  if (deepcount1 == -1) {

  retrycount = idlescan_countopen(proxy, target, ports, firstHalfSz, NULL,

  NULL);

  if (retrycount != flatcount1) {

  /* We have to do a deep count if new ports were found and

  there are more than 1 total */

  if (firstHalfSz > 1 && retrycount > 0) {

  retry2 = retrycount;

  retrycount = idle_treescan(proxy, target, ports, firstHalfSz,

  retrycount);

  adjust_idle_timing(proxy, target, retry2, retrycount);

  } else {

  if (o.debugging)

  error(“Adjusting timing because my first scan of %d ports, starting with %hu found %d open, while second scan yielded %d”, firstHalfSz, ports[0], flatcount1, retrycount);

  adjust_idle_timing(proxy, target, flatcount1, retrycount);

  }

  totalfound += retrycount – flatcount1;

  flatcount1 = retrycount;

  /* If our first count erroneously found and added an open port,

  we must delete it */

  if (firstHalfSz == 1 && flatcount1 == 1 && retrycount == 0)

  target->ports.forgetPort(ports[0], IPPROTO_TCP);

  }

  }

  if (deepcount2 == -1) {

  retrycount = idlescan_countopen(proxy, target, ports + firstHalfSz,

  secondHalfSz, NULL, NULL);

  if (retrycount != flatcount2) {

  if (secondHalfSz > 1 && retrycount > 0) {

  retry2 = retrycount;

  retrycount = idle_treescan(proxy, target, ports + firstHalfSz,

  secondHalfSz, retrycount);

  adjust_idle_timing(proxy, target, retry2, retrycount);

  } else {

  if (o.debugging)

  error(“Adjusting timing because my first scan of %d ports, starting with %hu found %d open, while second scan yeilded %d”, secondHalfSz, ports[firstHalfSz], flatcount2, retrycount);

  adjust_idle_timing(proxy, target, flatcount2, retrycount);

  }

  totalfound += retrycount – flatcount2;

  flatcount2 = retrycount;

  /* If our first count erroneously found and added an open port,

  we must delete it. */

  if (secondHalfSz == 1 && flatcount2 == 1 && retrycount == 0)

  target->ports.forgetPort(ports[firstHalfSz], IPPROTO_TCP);

  }

  }

  }

  if (firstHalfSz == 1 && flatcount1 == 1)

  target->ports.setPortState(ports[0], IPPROTO_TCP, PORT_OPEN);

  if ((secondHalfSz == 1) && flatcount2 == 1)

  target->ports.setPortState(ports[firstHalfSz], IPPROTO_TCP, PORT_OPEN);

  return totalfound;

  }

  /* The very top-level idle scan function — scans the given target

  host using the given proxy — the proxy is cached so that you can keep

  calling this function with different targets. */

  void idle_scan(Target *target, u16 *portarray, int numports,

  char *proxyName, const struct scan_lists * ports) {

  static char lastproxy[MAXHOSTNAMELEN + 1] = “”; /* The proxy used in any previous call */

  static struct idle_proxy_info proxy;

  int groupsz;

  int portidx = 0; /* Used for splitting the port array into chunks */

  int portsleft;

  char scanname[128];

  Snprintf(scanname, sizeof(scanname), “idle scan against %s”, target->NameIP());

  ScanProgressMeter SPM(scanname);

  if (numports == 0) return; /* nothing to scan for */

  if (!proxyName) fatal(“idle scan requires a proxy host”);

  if (*lastproxy && strcmp(proxyName, lastproxy))

  fatal(“%s: You are not allowed to change proxies midstream. Sorry”, __func__);

  assert(target);

  if (target->timedOut(NULL))

  return;

  if (target->ifType() == devt_loopback) {

  log_write(LOG_STDOUT, “Skipping Idle Scan against %s — you can’t idle scan your own machine (localhost)./n”, target->NameIP());

  return;

  }

  target->startTimeOutClock(NULL);

  /* If this is the first call, */

  if (!*lastproxy) {

  initialize_idleproxy(&proxy, proxyName, target->v4hostip(), ports);

  strncpy(lastproxy, proxyName, sizeof(lastproxy));

  }

  /* If we don’t have timing infoz for the new target, we’ll use values

  derived from the proxy */

  if (target->to.srtt == -1 && target->to.rttvar == -1) {

  target->to.srtt = MAX(200000,2 * proxy.host.to.srtt);

  target->to.rttvar = MAX(10000, MIN(proxy.host.to.rttvar, 2000000));

  target->to.timeout = target->to.srtt + (target->to.rttvar << 2); } else { target->to.srtt = MAX(target->to.srtt, proxy.host.to.srtt);

  target->to.rttvar = MAX(target->to.rttvar, proxy.host.to.rttvar);

  target->to.timeout = target->to.srtt + (target->to.rttvar << 2);

  }

  /* Now I guess it is time to let the scanning begin! Since idle

  scan is sort of tree structured (we scan a group and then divide

  it up and drill down in subscans of the group), we split the port

  space into smaller groups and then call a recursive

  divide-and-counquer function to find the open ports */

  while(portidx < numports) {

  portsleft = numports – portidx;

  /* current_groupsz is doubled below because idle_subscan cuts in half */

  groupsz = MIN(portsleft, (int) (proxy.current_groupsz * 2));

  idle_treescan(&proxy, target, portarray + portidx, groupsz, -1);

  portidx += groupsz;

  }

  char additional_info[14];

  Snprintf(additional_info, sizeof(additional_info), “%d ports”, numports);

  SPM.endTask(NULL, additional_info);

  /* Now we go through the ports which were scanned but not determined

  to be open, and add them in the “closed|filtered” state */

  for(portidx = 0; portidx < numports; portidx++) { if (target->ports.portIsDefault(portarray[portidx], IPPROTO_TCP)) {

  target->ports.setPortState(portarray[portidx], IPPROTO_TCP, PORT_CLOSEDFILTERED);

  target->ports.setStateReason(portarray[portidx], IPPROTO_TCP, ER_NOIPIDCHANGE, 0, NULL);

  } else

  target->ports.setStateReason(portarray[portidx], IPPROTO_TCP, ER_IPIDCHANGE, 0, NULL);

  }

  target->stopTimeOutClock(NULL);

  return;

  }

  IP协议扫描

  IP协议扫描可以让您确定哪些IP协议(TCP,ICMP,IGMP等)是目标机器的支持。这不是技术上的端口扫描,因为只是IP协议号的循环而不是TCP或UDP端口号。

  命令:NMAP -sO 目标

Nmap备忘单:从探索到漏洞利用分析第二部分2

Nmap备忘单:从探索到漏洞利用分析第二部分2

  FTP弹跳扫描

  这允许用户连接到一个FTP服务器,然后文件被发送到目标主机。NMAP会发送文件到你指定的目标主机上的端口,通过错误消息判断该端口的状态。这是绕过防火墙的好方法,因为相对于Internet主机,组织的FTP服务器经常被放置在可被内网访问的范围中。它的格式为:@:。 是一个脆弱的FTP服务器的名称或IP地址。

  命令:NMAP Cb ftp rely host

  NMAP -T0-b username:password@ftpserver.tld:21 victim.tld

  这将使用用户名“username”,密码为“password”,FTP服务器“FTP server.tld”,ftp端口则是21,用于扫描的文件是服务器上的victim.tld。

  如果FTP服务器支持匿名登录,就不用填写“username:password@”部分。如果FTP端口是默认的21,也可以省略不写,但如果FTP端口是21之外的必须得指明。

  端口规范和扫描顺序

  除了所有的前面讨论的扫描方法,NMAP提供选项用于指定被扫描的端口和扫描顺序是随机的或顺序的。默认情况下NMAP扫描最常见的1000个端口。

  -p<端口范围>(只扫描指定的端口)

  此选项指定要扫描的端口范围,并覆盖默认。单个端口号都行,因为是用连字符(例如1-1023)分割范围。范围的起始或结束可以被省略,NMAP会分别使用1和65535。所以你可以指定-p-,相当于从1到65535进行扫描。

  NMAP -p1-1023 目标

  你可以指定用于端口扫描的协议类型,比如T代表TCP,U代表UDP,S代表SCTP,P代表IP。

  NMAP -p U:53,111,137,T:21-25,80,139,8080 目标

  -F(快速(有限的端口)扫描)

  指定比默认情况下更少的端口数。通常情况下的NMAP扫描每个扫描协议中最常见的1000个端口。用-F将会减少到100个。

  NMAP -F 目标

  -r(不要随机端口)

  默认情况下NMAP会随机扫描端口,但您可以指定-r为顺序(从最低到最高排序)端口扫描来代替。

  NMAP -r 目标

  在接下来的部分,我将使用NMAP绕过防火墙,创建自定义利用程序。

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