Introduction

0x03 Shells session presented by the UQ Cyber Squad. Access via OpenVPN connection. OpenVPN configuration bundle provided during the workshop.

Challenge 1 - Family Binding Time - 10pts

Let’s bind together at 192.168.57.11:8297

nc 192.168.57.11 8297
id
uid=1002(user) gid=1002(user) groups=1002(user)
pwd
/home/user
ls -las
total 60
 4 drwxr-xr-x 3 user    user  4096 Mar 27 06:02 .
 4 drwxr-xr-x 4 root    root  4096 Mar 24 02:13 ..
 4 -rw------- 1 user    user  1584 Mar 26 01:26 .bash_history
 4 -rw------- 1 user    user   105 Mar 26 00:50 .lesshst
 4 -rw------- 1 user    user     5 Mar 24 03:38 .python_history
 4 drwxr-xr-x 2 user    user  4096 Mar 26 00:59 .ssh
 8 -rw------- 1 user    user  5066 Mar 27 06:01 .viminfo
 4 -r-xr-xr-x 1 root    user   892 Mar 27 06:02 init_shell.py
20 -rwsr-xr-x 1 richard root 16728 Mar 26 00:54 read_secret_message
 4 -rw-r--r-- 1 user    user    24 Mar 24 02:14 user.txt
cat user.txt	
flag{n1c3_b0nd1ng_t1m3}

Challenge 2 - shhhhhhhh - 20pts

How do I ssshhhhh? How do I know how to?

Git is yet another open source version control, and seems to be the tool of choice for contemporary coding mavericks. I still prefer svn and cvs, for centralised version control, but can appreciate why some projects may require distributed repositories as afforded by git.

Setting up a central git repository on a server is easy. You basically setup a user, whose home directory is used to store the repositories, and allow access to people using keys, where the user retain their private key and their public key is saved as an authorised key for the git user account.

Denyhosts is another utility similar to fail2ban. It parses log files to identify potential attacks against SSH services. A clear advantage that Denyhosts has over fail2ban is the synchronisation mechanism since version 2.0[1]. Denyhosts permits communication with a central server to exchange information about denied hosts by other Denyhosts daemons. However unlike fail2ban, it does not modify any firewall (iptables) rules, instead it relies on tcpwrapper and the hosts.deny file to block ssh access. Fail2ban also offers the advantage of monitoring other services and logs, whereas Denyhosts is specific to SSH. There are other utilities which use tcpwrapper such which can handle additional services[2].