CIS 290 LINUX Security Basic Network Security “Chroot Jail”

Network services Determine open services: netstat –tulpn -OR- nmap -sT -O localhost Disable with chkconfig. And/or remove software. Use TCP_WRAPPERS (xinetd) Configure iptables Remove Xwindows: yum groupremove "X Window System“ Set initdefault to runlevel 3 No cleartext services HTTP, TELNET, FTP, rcmd, (see gov’t requirements) - use SSH, SSL, SFTP. Restrict NFS/CIFS to local networks only. Basic tools: ping, traceroute, netstat, nmap, netcat (nc) telnet

Chroot jail Isolate user process within a “virtual” root file system. Similar to web “virtual document root” or vsftpd “chroot_local_user=YES”. As root: chroot Trick is to automate the process for user login, file transfer (sftp) or specific applications. Most daemon processes have their own “chroot” methodology. Not as secure, less isolating as LINUX containers or Solaris zones (CIS 228) for specific application environnments.

Google Hacking We can use a standard Google search to find interesting pages such as indexes. - “index of /etc” - “index of /etc” passwd - “index of /etc” shadow Google allows us to do more than just simple searching using advanced operators E.g. – filetype: – inanchor: – intext: – intitle: – inurl: – site:

Using Advanced Operators We can now search in the Title field for indexed pages: intitle:index.of./etc passwd intitle:index.of./etc shadow We can use the filetype: operator: password filetype:xls filetype:config web.config -CVS filetype:mdb users.mdb Combining Operators filetype:eml eml +intext:"Subject" +intext:"From" +intext:"To“ "# -FrontPage-" ext:pwd inurl:(service | authors | administrators | users) "# -FrontPage-" inurl:service.pwd

Google Hacking Database (GHDB) Thousands of search URL’s Javascript: entries very powerful Enter Wikto – Web Server Assessment Tool - Back-end Miner - Nikto-like functionality - Googler file searcher - GoogleHacks GHDB tester