标签：数字转换 names UI 解码 icm ram star utf-8 win
在书中已知通过向主机不常用端口发送UDP数据包，通过是否有不可达的信息返回包来判断主机是否存活。 等待ICMP响应
import socket import os # 监听的主机 host = "172.16.0.143" # 创建原始套接字，然后绑定在公开接口上 if os.name == "nt": #windows os.name =nt windows允许我们嗅探所有协议的所有数据包 LINUX智能嗅探ICMP socket_protocol = socket.IPPROTO_IP else: socket_protocol = socket.IPPROTO_ICMP sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol) sniffer.bind((host, 0)) # 设置在捕获的数据包中包含IP头 sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1) # 如果在windows下 需要设置IOCTL以启用混杂模式 if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON) # 读取一个单独的数据包 print sniffer.recvfrom(65565) # 在windows下关闭混杂模式 if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)
运行脚本 ping一下 可以抓到相应ICMP数据包
在此模式下 嗅探器可以接收任何高层协议 如TCP、UDP或ICMP的所有的IP头信息。这些信息被打包成二进制数的形式
如上图。
接下来的一个脚本 是来解析这些信息 并把IP头的部分 提取并翻译成人类能懂的形式。
# -*- coding: UTF-8 -*- import socket import os import struct from ctypes import * # 监听的端口 host = "172.16.0.143" class IP(Structure): _fields_ = [ ("ihl", c_ubyte, 4), ("version", c_ubyte, 4), ("tos", c_ubyte), ("len", c_ushort), ("id", c_ushort), ("offset", c_ushort), ("ttl", c_ubyte), ("protocol_num", c_ubyte), ("sum", c_ushort), ("src", c_uint), ("dst", c_uint) ] #定义一个dic def __new__(self, socket_buffer=None): #传递一下 return self.from_buffer_copy(socket_buffer) def __init__(self, socket_buffer=None): # 协议字段与协议名称对应 self.protocol_map = {1:"ICMP", 6:"TCP", 17:"UDP"} #定义一个字典 分析数据里的数字 对照对应的协议 # 可读性更强的IP地址 self.src_address = socket.inet_ntoa(struct.pack("<L",self.src)) # 把一堆数据 按照人类可以理解的IP地址去转换 源地址IP self.dst_address = socket.inet_ntoa(struct.pack("<L",self.dst)) #目标地址IP #协议类型 try: self.protocol = self.protocol_map[self.protocol_num] #把数字转换成名字 except: self.protocol = str(self.protocol_num) # 跟上一段代码类似 if os.name == "nt": socket_protocol = socket.IPPROTO_IP else: socket_protocol = socket.IPPROTO_ICMP sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol) sniffer.bind((host, 0)) # we want the IP headers included in the capture sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1) # if we‘re on Windows we need to send some ioctls # to setup promiscuous mode if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON) try: while True: # read in a single packet raw_buffer = sniffer.recvfrom(65565)[0] # 将缓冲区的前20个字节按IP头进行解析 ip_header = IP(raw_buffer[0:20]) #输出协议和通信双方的IP地址 print "Protocol: %s %s -> %s" % (ip_header.protocol, ip_header.src_address, ip_header.dst_address) except KeyboardInterrupt: # if we‘re on Windows turn off promiscuous mode if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)
有了上一段代码我们就能嗅探解码任何数据的IP层，因为发送UDP数据到关闭的端口时会产生ICMP相应，所以我们还需要对ICMP数据进行解码。ICMP内容中包含的信息非常繁杂，但每条信息都包含三个固定的字段
所以我们要解码ICMP
我们扫描器的目标是查找类型值位3，代码值也位3的ICMP数据包。这种ICMP的响应数据意味着目标不可达，而代码值为3是由于目标主机产生了端口不可达的错误
添加代码实现ICMP数据包的解码功能。
import socket import os import struct import threading from ctypes import * # host to listen on host = "172.16.0.50" class IP(Structure): _fields_ = [ ("ihl", c_ubyte, 4), ("version", c_ubyte, 4), ("tos", c_ubyte), ("len", c_ushort), ("id", c_ushort), ("offset", c_ushort), ("ttl", c_ubyte), ("protocol_num", c_ubyte), ("sum", c_ushort), ("src", c_uint), ("dst", c_uint) ] def __new__(self, socket_buffer=None): return self.from_buffer_copy(socket_buffer) def __init__(self, socket_buffer=None): # map protocol constants to their names self.protocol_map = {1:"ICMP", 6:"TCP", 17:"UDP"} # human readable IP addresses self.src_address = socket.inet_ntoa(struct.pack("<L",self.src)) self.dst_address = socket.inet_ntoa(struct.pack("<L",self.dst)) # human readable protocol try: self.protocol = self.protocol_map[self.protocol_num] except: self.protocol = str(self.protocol_num) class ICMP(Structure): _fields_ = [ ("type", c_ubyte), ("code", c_ubyte), ("checksum", c_ushort), ("unused", c_ushort), ("next_hop_mtu", c_ushort) ] def __new__(self, socket_buffer): return self.from_buffer_copy(socket_buffer) def __init__(self, socket_buffer): pass # create a raw socket and bind it to the public interface if os.name == "nt": socket_protocol = socket.IPPROTO_IP else: socket_protocol = socket.IPPROTO_ICMP sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol) sniffer.bind((host, 0)) # we want the IP headers included in the capture sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1) # if we‘re on Windows we need to send some ioctls # to setup promiscuous mode if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON) try: while True: # read in a single packet raw_buffer = sniffer.recvfrom(65565)[0] # create an IP header from the first 20 bytes of the buffer ip_header = IP(raw_buffer[0:20]) print "Protocol: %s %s -> %s" % (ip_header.protocol, ip_header.src_address, ip_header.dst_address) # if it‘s ICMP we want it if ip_header.protocol == "ICMP": # calculate where our ICMP packet starts offset = ip_header.ihl * 4 buf = raw_buffer[offset:offset + sizeof(ICMP)] # create our ICMP structure50 icmp_header = ICMP(buf) print "ICMP -> Type: %d Code: %d" % (icmp_header.type, icmp_header.code) # handle CTRL-C except KeyboardInterrupt: # if we‘re on Windows turn off promiscuous mode if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)
import socket import os import struct import threading from netaddr import IPNetwork,IPAddress from ctypes import * # host to listen on host = "172.16.0.36" # subnet to target subnet = "172.16.0.1/24" #扫描的目标子网 # 自定义的字符串 ，我们将在ICMP响应中进行核对。 magic_message = "PYTHONRULES!" def udp_sender(subnet,magic_message): sender = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # 批量发送UDP数据包 for ip in IPNetwork(subnet): try: sender.sendto(magic_message,("%s" % ip,65212)) except: pass class IP(Structure): _fields_ = [ ("ihl", c_ubyte, 4), ("version", c_ubyte, 4), ("tos", c_ubyte), ("len", c_ushort), ("id", c_ushort), ("offset", c_ushort), ("ttl", c_ubyte), ("protocol_num", c_ubyte), ("sum", c_ushort), ("src", c_uint32), ("dst", c_uint32) ] def __new__(self, socket_buffer=None): return self.from_buffer_copy(socket_buffer) def __init__(self, socket_buffer=None): # map protocol constants to their names self.protocol_map = {1:"ICMP", 6:"TCP", 17:"UDP"} # human readable IP addresses self.src_address = socket.inet_ntoa(struct.pack("<L",self.src)) self.dst_address = socket.inet_ntoa(struct.pack("<L",self.dst)) # human readable protocol try: self.protocol = self.protocol_map[self.protocol_num] except: self.protocol = str(self.protocol_num) class ICMP(Structure): _fields_ = [ ("type", c_ubyte), ("code", c_ubyte), ("checksum", c_ushort), ("unused", c_ushort), ("next_hop_mtu", c_ushort) ] def __new__(self, socket_buffer): return self.from_buffer_copy(socket_buffer) def __init__(self, socket_buffer): pass # create a raw socket and bind it to the public interface if os.name == "nt": socket_protocol = socket.IPPROTO_IP else: socket_protocol = socket.IPPROTO_ICMP sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol) sniffer.bind((host, 0)) # we want the IP headers included in the capture sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1) # if we‘re on Windows we need to send some ioctls # to setup promiscuous mode if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON) # start sending packets t = threading.Thread(target=udp_sender,args=(subnet,magic_message)) t.start() try: i=1 while True: # read in a single packet raw_buffer = sniffer.recvfrom(65565)[0] # create an IP header from the first 20 bytes of the buffer ip_header = IP(raw_buffer[0:20]) #print "Protocol: %s %s -> %s" % (ip_header.protocol, ip_header.src_address, ip_header.dst_address) # if it‘s ICMP we want it if ip_header.protocol == "ICMP": # calculate where our ICMP packet starts offset = ip_header.ihl * 4 buf = raw_buffer[offset:offset + sizeof(ICMP)] # create our ICMP structure icmp_header = ICMP(buf) #print "ICMP -> Type: %d Code: %d" % (icmp_header.type, icmp_header.code) # now check for the TYPE 3 and CODE 3 which indicates # a host is up but no port available to talk to if icmp_header.code == 3 and icmp_header.type == 3: # check to make sure we are receiving the response # that lands in our subnet if IPAddress(ip_header.src_address) in IPNetwork(subnet): # test for our magic message if raw_buffer[len(raw_buffer)-len(magic_message):] == magic_message: print "%d Host Up: %s" % (i,ip_header.src_address) # handle CTRL-C except KeyboardInterrupt: # if we‘re on Windows turn off promiscuous mode if os.name == "nt": sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)
标签：数字转换 names UI 解码 icm ram star utf-8 win
原文地址：http://www.cnblogs.com/singledan/p/7183490.html
