CIS 290 LINUX Security
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Learn about securing Linux systems by using techniques such as chroot jail, configuring iptables, and disabling cleartext services. Also, discover how to leverage Google hacking techniques for advanced searching.
CIS 290 LINUX Security
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Presentation Transcript
CIS 290LINUX 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 <directory path> <command> • 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