Your Inner Sysadmin - LonestarPHP 2015
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One thing that most programmers do not take the time to understand is the servers that their application lives on. Most know a smattering of Apache configs, PHP configs, and basic information about the OS. This talk will deal with looking at tools that can help you quickly set up a server and how it can help you be a better developer. We'll look at tools like puppet for server management, OSSEC for log management, different command line tools, and nagios/monit for system monitoring.
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Your Inner Sysadmin - LonestarPHP 2015
- 1. Your Inner Sysadmin Chris Tankersley @dragonmantank LonestarPHP 2015 LonestarPHP 2015 1
- 2. Who Am I • PHP Programmer for over 10 years • Sysadmin/DevOps for around 8 years • Using Linux for more than 15 years • hFps://github.com/dragonmantank LonestarPHP 2015 2
- 3. Here Be Dragons LonestarPHP 2015 3
- 4. Traditional Lamp Stack LonestarPHP 2015 4
- 6. And of course… LonestarPHP 2015 6
- 7. The Server • /bin -‐ EssenPal user executable files • /boot -‐ Stuff that makes the OS boot up! • /dev -‐ Special device stuff you probably won't touch • /etc -‐ ConfiguraPon files • /home -‐ User home directories • /sbin -‐ System binaries • /usr -‐ MulP-‐user apps and uPliPes • /var -‐ Data usually lives here LonestarPHP 2015 7
- 8. Installing Software • Compile soXware from scratch • Use the package manager (yum/apt) LonestarPHP 2015 8
- 9. Learn to love the Command Line LonestarPHP 2015 9
- 10. Learn a CLI text editor • vi/vim • emacs • nano LonestarPHP 2015 10
- 11. Authentication and Authorization LonestarPHP 2015 11
- 12. SSH Keys • SSH generally uses a Username/Password • SSH Keys pass a public key to the server • Can use a single key for mulPple machines, or mulPple keys for mulPple machines • More secure since ‘passwords’ cannot be stolen LonestarPHP 2015 12
- 13. sudo You can give admin access to users (or groups of users) without giving them root. LonestarPHP 2015 13 # Add sudo access to a single user to run as root dragonmantank ALL=(ALL) ALL # Add sudo access to a full group %admin ALL=(ALL) ALL You can even restrict what commands the users can run # Restrict web developers to only restart Apache and MySQL %webdevs 192.168.1.0/255.255.225.0=(root) NOPASSWD:/usr/sbin/service apache2 restart, /usr/sbin/service mysql restart
- 14. Jailing Users Keeps people from geang to things they shouldn't. Protects the users from themselves. LonestarPHP 2015 14
- 15. Jailed Shells Gives users a full shell but not the enPre file system. You can pick and choose what programs the user can have access too. Jailkit makes this incredibly easy to set up. LonestarPHP 2015 15
- 16. Jailed SFTP Locks the user to a specific base path, but doesn’t give them a shell, much like FTP. You get the security of SSH though! It does require a system user however. LonestarPHP 2015 16
- 17. Jailing SFTP # In /etc/ssh/sshd_config Subsystem ftp sftp-‐internal # At the bottom of the file Match User jailedsftp ChrootDirectory /some/path AllowTCPForwarding no X11Forwarding no ForceCommand sftp-‐internal LonestarPHP 2015 17
- 18. Docker LonestarPHP 2015 18 If you do it the non-‐Docker way
- 20. Bash Most servers use bash as the default shell. Most shells understand bash's syntax. If you find yourself running the same commands over and over, throw it in a bash script. LonestarPHP 2015 20
- 21. Python Ships with most distros. Great for when you need more power than what bash has. LonestarPHP 2015 21
- 22. PHP! Leverage your PHP skills to write shell scripts. • Symfony Console Component • Aura CLI LonestarPHP 2015 22
- 23. Locking Down your Code LonestarPHP 2015 23
- 24. Running Apache as a different user MPM-‐ITK LonestarPHP 2015 24 MOD_RUID2 <IfModule mpm_itk_module> AssignUserId [user] [group] </IfModule> RMode config RUidGid myuser mygroup RDocumentChRoot /var/www/vhosts/domain.com/ www/public
- 25. PHP-FPM user = myuser group = mygroup chroot = /path/to/my/chroot LonestarPHP 2015 25
- 26. Logs LonestarPHP 2015 26
- 27. Logrotate Rotates logs out for organizaPon (or other purposes) LonestarPHP 2015 27 weekly rotate 4 create include /etc/logrotate.d /var/log/wtmp { monthly minsize 1M create 0664 root utmp rotate 1 }
- 28. Logwatch Script that runs every so oXen and scans a bunch of logs so you get a preFy e-‐mail with a summary of events LonestarPHP 2015 28 -‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐ httpd Begin -‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐ 0.17 MB transferred in 792 responses (1xx 0, 2xx 786, 3xx 0, 4xx 6, 5xx 0) 199 Content pages (0.09 MB), 593 Other (0.09 MB) Requests with error response codes 400 Bad Request /w00tw00t.at.ISC.SANS.DFind:): 1 Time(s) 404 Not Found /MyAdmin/scripts/setup.php: 1 Time(s) /phpmyadmin/scripts/setup.php: 1 Time(s) /w00tw00t.at.blackhats.romanian.anti-‐sec:): 1 Time(s) /webdav/: 2 Time(s) -‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐ httpd End -‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐
- 29. OSSEC Actually a Host Intrusion DetecPon system, but it does this by watching logs. Will alert you immediately to problems, and even shut down the aFacks. LonestarPHP 2015 29 OSSEC HIDS Notification. 2012 Oct 24 11:38:10 Received From: maple-‐>/var/log/auth.log Rule: 5712 fired (level 10) -‐> "SSHD brute force trying to get access to the system." Portion of the log(s): Oct 24 11:38:09 maple sshd[1062]: Failed password for invalid user alias from 199.167.138.44 port 59988 ssh2 Oct 24 11:38:07 maple sshd[1062]: Invalid user alias from 199.167.138.44 Oct 24 11:38:06 maple sshd[1059]: Failed password for invalid user recruit from 199.167.138.44 port 59884 ssh2
- 31. hosts.deny and hosts.allow Set of files to allow or deny access to the machine or certain apps/ ports on the machine LonestarPHP 2015 31
- 32. IPTables A firewall that is generally available on Linux machines that can be configured many different ways to allow or block or mangle traffic LonestarPHP 2015 32
- 33. OSSEC IDS that was logs and will use hosts.deny and iptables to block stuff automaPcally for you! LonestarPHP 2015 33
- 35. What is Configuration Management? Process by which you figure out what goes on your servers, how you want them set up, and keeping track of that informaPon. Files are usually stored in source control on one server and pushed to clients. LonestarPHP 2015 35
- 36. Why do you need it? • Ever needed to keep track of when files get changed? • Ever needed to roll back a change? • Ever needed to push the same change to a bunch of servers • Ever needed to set up a server exactly the same way as another server? LonestarPHP 2015 36
- 37. General CM Workflow LonestarPHP 2015 37 Write a Manifest file Client checks and compiles the manifests Client makes changes based on manifests
- 41. Quick Poll • Who here knows that their server is up right now? • Are all of the required services running? • Are there enough resources currently available? LonestarPHP 2015 41
- 42. Service Monitoring with Monit LonestarPHP 2015 42
- 43. Host Monitoring with Icinga LonestarPHP 2015 43
- 45. tmux/screen Command line mulPplexer LonestarPHP 2015 45
- 46. tail Look at the newest entries in a log, or even watch log files as they are generated LonestarPHP 2015 46
- 47. curl Command line program for transferring data via a URL LonestarPHP 2015 47
- 48. iftop Displays a breakdown of bandwidth usage by host LonestarPHP 2015 48
- 49. htop Slightly beFer interface for checking memory and CPU usage LonestarPHP 2015 49
- 50. tcpdump Allows you to view and record data transmiFed over the network. Couple this with wireshark and you can inspect the packets! LonestarPHP 2015 50
- 51. Servers for Hackers Chris Fidao @fideloper hFp://serversforhackers.com LonestarPHP 2015 51
- 52. Questions? LonestarPHP 2015 52