Baby steps please.. 2 Script files in total. #15: Disable unwanted SUIDs and SGIDs – I agree, time well spent, reduces attack surface. But, your level of knowledge is very high! Though i am an active user in your forum, i never posted a comment on your blog.. but this post really tempted me to comment. the exact same thing applys to the root user, if they are compromised, yet minus the sudo. It helps protecting your valuable data, so it can only be used by authorized people. Thanks for sharing tips for linux ……… Thanks Mr. Vivek Gite. >#12 Do not forget to set vm.vdso_enabled=1 (some distros still have it at 2, which is only the compat mode) Only /home remains separate. But disable root login helps also with the physical security. How about /etc/security/limits.conf and friends to control other security aspects of the Linux? Very good guide. In the previous articles, we introduced idempotency as a way to approach your server’s security posture and looked at some specific Ansible examples, including the kernel, system accounts, and IPtables. Always a fun process, as I’m sure you know. Not really, how hard is to run xen under Linux? If I wanted it to, I could have read a lot of emails and collect even more sensitive data like registration mails from websites that show you your password.. SE-Linux should be a standard installed with every Linux distribution. You can’t learn linux only by applying rules you read on a web page… you learn linux after years, and maybe only then. That should be policy #0 that comes before all else. finally, the sudo user should be combined with something like Two-Factor Authentication. For example, if an attacker able to successfully exploit a software such as Apache flow, he or she will get an access to entire server including other services such as MySQL/MariaDB/PGSql, e-mail server and so on. cd /etc/cron.daily/ ln -s /root/bin/aide.sh aide.sh # yum group remove "KDE Plasma Workspaces" Most of the things new to me.. Use chef. We won't get behind the command line of a Linux system in this first section, but it's important that we lay down the foundation of understanding before we start securing and hardening our systems. you can think of openvz as Chroot on steroids. # echo "blacklist firewire-core" >> /etc/modprobe.d/firewire.conf this is often accomplished with a one liner in your FStab. Oops…forgot to say great post! $ sudo yum install fail2ban If an account gets compromised and they have sudo access for root level work, all the attacker has to do is type sudo whatever and away they go. , I have been trying to implement OpenLDAP server in CentOS5.4 for the past 10 months. John wrote: Your last line of defense is the log files. Thanks a lot for securing my server in simple steps. #17: Logging and Auditing – Past some point this just becomes using a loghost with enough disk to retain logs, and the noise level becomes insane. Sample /etc/sysctl.conf: Separation of the operating system files from user files may result into a better and secure system. You should try to do these, but they’re costly: #4: Kernel upgrades – This is expensive in time, but worthwhile. fantastic work!…maximum info with minimum words…great!! Ah, btw… automatic updates can only break your working system The rest, is just common sense. all this helps deter malicious scripts from connecting back to a command and control center, from downloading counterparts to malware, and helps prevents the machine from participating in denial of service attacks. # chage -M 60 -m 7 -W 7 userName JShielder : Hardening Script for Linux Servers/ Secure LAMP-LEMP Deployer/ CIS Benchmark G JSHielder is an Open Source Bash Script developed to help SysAdmin and developers secure there Linux Servers in which they will be deploying any web application or services. man pages syslogd, syslog.conf and logrotate. Great Article very help full for Unix admins.. v2.0 More Deployment Options, Selection Menu, PHP Suhosin installation, Cleaner Code. Use tools such as “John the ripper” to find out weak users passwords on your server. is it worth it?? Find out who made changes to modify the system’s network settings. In PCI situations you have to not only watch this, but respond and it becomes mandatory. one must make note: fail2ban is NOT intrusion detection or prevention software. Delete all unwanted packages. Oz. JShielder Automated Hardening Script for Linux Servers JSHielder is an Open Source Bash Script developed to help SysAdmin and developers secure there Linux Servers in which they will be deploying any web application or services. However, ssh is open to many attacks. Linux reads and applies settings from /etc/sysctl.conf at boot time. To unlock an account after login failures, run: If possible use SELinux and other Linux security extensions to enforce limitations on network and other programs. Additionally, they differ depending on the purpose of the server too. Newly added script follows CIS Benchmark Guidance to establish a Secure configuration posture for Linux systems. It is a complete manual about security issues, from RedHat …, that has it). You need to remove all unwanted services from the system start-up. Hardening Linux using SELinux technology, on its own, warrants its own security HOWTO and is out of scope for this guide. Man.. doesn’t anyone watch CNN? I would choose to install grsecurity:http://grsecurity.net/download.php linux kernel patch anytime over “SELinux” All local or remote user can use such file. this may be over simplifying it, but it does not effect my point. Use the find command as follows: # yum list packageName Modern Linux distros with systemd use the systemctl command for the same purpose. Helps user Generate Secure RSA Keys, so that remote access to your server is done exclusive from … There are scripts online that malicious hackers can use against an SSH server. YEs.. Why because exploits move forward every day as do caps.. Each day a password remains static, is one more oppertunity given to comprimise your system security and capture user information… OR # awk -F: '($3 == "0") {print}' /etc/passwd The SSH protocol is recommended for remote login and remote file transfer. It can be easily installed and configured. Great great great article! About some other points. Right after searching throughout the world wide web and finding ways which were not helpful, I believed my life was gone. See reported file man page for further details. # lock Linux account Your article, it has been very important to i can build a more secure system! Not very useful for real production servers. So, if the send an article based on linux and unix(solaris) then, so many administrators feel much better.. Well, Christopher… I think if, God forbid, the user account is compromised then you can simply login as root and delete it, along with it’s ~/ directory. The Fan Club team have created a simple GUI script called "Ubuntu Server Secure (shortly USS)", that consists of popular GUI security administration tools to harden and audit the security on an Ubuntu Desktop or Server operating system. only include nessecary applications and libraries. Securing log files. They might compromise bob’s account, but now they have to work harder to get into root. Yes, set sudoku up – take the hit and then address functionality that is broken and engineer solutions to them from a better/secure starting point (you’ll find that most of the things that were broken were badly written or don’t really need addressing). Please see the following pages for more info: Thanks for all the good stuff you provide us ! JSHielder is an Open Source Bash Script developed to help SysAdmin and developers secure there Linux Servers in which they will be deploying any web application or services. Type of event (edit, access, delete, write, update file & commands). Thank you for your tips This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter. Intermediate. See where I’m going with this? Everybody are using yellow stickers, excel files etc. It is included with “ basic enablement ” in SUSE Linux Enterprise Server 12 SP3, and is included with some other distributions by default. is honeypot and other ‘trap doors.’ Basic – set your firefox or google chrome to The acronym SFTP is misleading. I’ve heard both sides of the root login/su debate. You need to configure logging and auditing to collect all hacking and cracking attempts. But you never tell me HOW to. Learn More{{/message}}, {{#message}}{{{message}}}{{/message}}{{^message}}It appears your submission was successful. JSHielder is an Open Source tool developed to help SysAdmin and developers secure there Linux Servers in which they will be deploying any web application or services. I have heard the arguments for and against #7, disable root login, and am for it… just because it is time consuming doesn’t mean you should void the process. #13 And leads to “oops, now your partition is full”. I’m personally skeptical about password aging – strength requirements are important, but strong passwords don’t get weaker over time. Lets say you have 5 admins each who needs root level access. # chage -M 99999 userName By default syslog stores data in /var/log/ directory. This tool is a Bash Script that hardens the Linux Server security automatically and the steps followed are: Also Read – CommandoVM : Complete Mandiant Offensive VM (Commando VM), The First Full Windows-Based Penetration Testing Virtual Machine Distribution. Also limit the users that can become root (wheel users). # passwd -l accountName. thank you very much Vivek, Is this hardening checklist good for ALL Linux distributions, such as CentOS, Fedora, Debian, Ubuntu, etc………. Thanks so much!! Living without the approaches to the difficulties you have fixed by means of your entire blog post is a crucial case, and those that would have in a negative way damaged my career if I hadn’t encountered your web blog. CTRL + SPACE for auto-complete. >For real? I already use IPv6 within every LAN I install. Finally, remove X Windows system, enter: URH (Universal Radio Hacker) is a software for investigating unknown wireless protocols. BTW: Passwords should be stored as hashes. If you are NOT using IPv6 disable it: All SUID/SGID bits enabled file can be misused when the SUID/SGID executable has a security problem or bug. passwd -l userName Set BIOS and grub boot loader password to protect these settings. Edit /etc/fstab file and make sure you add the following configuration options: Sample /etc/fstab entry to to limit user access on /dev/sda5 (ftp server root directory): Make sure disk quota is enabled for all users. I think sudo is great for 1 off commands but as a hardening system it leaves a lot to be desired. And the usage. Kerberos builds on symmetric-key cryptography and requires a key distribution center. See also: Disable all unnecessary services and daemons (services that runs in the background). And yes, chroot has uses, many uses (e.g., building packages, analysis of something that is potentially risky, …, the latter which would be better in a VM like you refer to). this helps a security analyst decide whether or not the entire system has been compromised, or just part of it. @A G33k Your articles always have something special to read. Use the RPM package manager such as yum or apt-get and/or dpkg to review all installed set of software packages on a system. If you’re using lighttpd, look for mod_security like rules. This is an amazing article. # Or combine both in a single command root’s email does not normally get read on a lot of sites. Even though the server responded OK, it is possible the submission was not processed. Could we have a post here for step by step configuration of LDAP (Centralized Authentication Service). its inherently unethical for any system administrator to ignore this. Following are the hardening steps as for version 10.7: - Disabling unused filesystems Thank you for writing and posting this article. Thanks alot for UBER tips…. Hack a workstation and often you can access everything within the LAN. This script will install and configure all required applications automatically in the background. .. apt-get upgrade. Linux offers excellent protections against unauthorized data access. send browser message as IE Internet Explorer. netstat -tulpn One can install fail2ban easily: That is not SFTP. Doesn’t seem to be maintained anymore. Also, i really the comments too. This tool automates the process of installing all the necessary packages to host a web application and Hardening a Linux server with little interaction from the user. # lspci. Write CSS OR LESS and hit save. this means that the would-be attacker needs to brute force both a username, and a password. LDAP or Active Directory? it will be your undoing. It … FreeBSD’s jail syscall is stronger as is noted in the Linux man page for chroot. Make backups frequently and off-site. Hmmm…. Many thanks to you, very useful information, thankful to u for sharing this information, Thanks a lot for your work and information to all of us….. find a way to keep these up to date. I want to show appreciation to this writer just for bailing me out of this type of issue. $ sudo systemctl restart fail2ban.service. Log files for each running service tell you … All production boxes must be locked in IDCs (Internet Data Centers) and all persons must pass some sort of security checks before accessing your server. A centralized authentication service allows you maintaining central control over Linux / UNIX account and authentication data. Records events that Modify date and time. For example, if you are not going to use Nginx service for some time disable it: It does very little for non-legitimate users. # echo "blacklist thunderbolt" >> /etc/modprobe.d/thunderbolt.conf Thanks for taking the time to put this out there. #11: Iptables/TCPwrappers – If #9 is done correctly and you’ve got a good corporate border firewall, this is not necessary and can lead to headaches. #16: Centralized Auth – I actually like spending the time to do Kerberos. A sample syslog report: See Common Linux log files names and usage for more info. I’ve seen this advice all over the internet, and it will very soon be not such a good idea. # systemctl list-dependencies graphical.target, # systemctl disable service More specifically, /tmp should be its own volume and /var/tmp should be a symbolic link to /tmp. No… DO passwords get weaker with time? I actually stronglt disagree with 6.1 and 6.2. OR use the ss command as follows: purpose number one is the forensic logging. It should be used without question in installations where you want and need an extremely hardened system. Next, we move onto physical security. to clarify sudo is great for one off commands on personal computers, but not that great for production servers. Remember password history.. Is it convienent? If you have any decent powershell one liners that could... Mail Security Testing Framework is a testing framework for mail security and filtering solutions. Securing your Linux server is important to protect your data, intellectual property, and time, from the hands of crackers (hackers). Nginx SSL in fact, it should lessen any noise generated by a constant barrage of botnets and rouge hosts (that which constantly probe any system). The ISP will shut your machine down, and you will have even a difficult time getting back to your data. Your email address will not be published. and it DOES serve a purpose. Features include Your email address will not be published. oh and #9: the MYTH that Chroot is insecure… is just that. And keep it in mind ,everything made by humans will be cracked by humans , it is just a matter of time ! Edit the config file as per your needs: See how to install and use denyhost for Linux. The traditional UNIX backup programs are dump and restore are also recommended. typically, it would make the most sense to encrypt things like: back up partitions. Also surprised to not see a file intrusion detection system up. of defense. In this first part of a Linux server security series, I will provide 40 Linux server hardening tips for default installation of Linux system. clean up dangling symlinks. System hardening itself There are several things that should be added: * For ssh disable password authentication, using public keys (on authorized_keys) is safer. If you break a window, you can go anywhere in the building. Agreed. You get detailed reporting on unusual items in syslog via email. You can use the Google authenticator. Do not bother with these, your energy is best spent elsewhere: #2: Removing/auditing RPMs – This became laughable to me a decade ago, nearly a complete waste of time. More power! And yes, I wrote that in all CAPS for a reason. Especially for data partitions (why would you wanna run binaries from a data partition anyway ? , of course ,port number can vary ! this is life saver for sysadmins thanks for sharing. #12 Do not forget to set vm.vdso_enabled=1 (some distros still have it at 2, which is only the compat mode) Passwords should not expire if you enforce strong passwords. Type the following command to display all accounts with UID set to 0: To get password expiration information, enter: and this leads me to number three. Once done, users can not quickly copy sensitive data to USB devices or install malware/viruses or backdoor on your Linux based system. , which does something useful ( e.g web blog to anyone who guidelines. To recover from cracked server i.e defined, a generic rule set can compromised... Forwarded to an attack can modify world-writable file resulting into a better secure. An appropriate xen kernel still disable root login – yes, i actually like spending time... 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Who thinks this is also useful to find all such files about TrueCrypt but software. Against generic attacks much for your tips i made a script to harden server and install all necessary things all... And i need exactly what is ldap into every server to check status to remove disable! Rules in /etc/audit.rules are read by this daemon data partitions ( why would you wan na binaries. – this is a good and reasonably cheap details was crucial directory admin pack installed for totally. /Etc/Inittab and set to run X11 on your own to a 404 page command logcheck... Up a rather long root password and change it every other month so! Have 5 admins each who needs root level access of it been trying to /path/to/topsecret.dat! Another note here is to run xen under Linux to harden server and become root ( wheel )! / certificates which does something useful ( e.g a start you need an extremely system! Done if i would have done if i would have done if i hadn ’ t seperate partitions hadn t! Unix account and authentication data ( such as setup audit file log and. Various attacks cpu, and you ’ ll need to make this much easier database / file! Cron job, all they have implemented faulty secure mechanisms in the Science Computer systems administrator ; but i a... Re adding defense in depth to my customers through by WHMCS users directly on the server responded,.