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Suse Hardening


 Linux security

Softpanorama Laws of Computer Security

Recommended Books

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Red Hat security


Suse Hardening
Apparmor Seccheck Pure-FTPd configuration Applying Patches in SLES Baseliners  Computer Security Intrusion Detection Unix/Linux Security-related Perl Scripts

wheel group


Disabling Unnecessary Services

  RPMs SecurId


  1. Modify /etc/sudoers to allow members of wheel group to su to root. 
  2. ___ Delete redundant accounts:
  3. ___ Delete redundant groups
  4. ___  Modify /etc/issue & motd according to company standards
  5. ____ Configure syslog-ng to report to remote host if such infrastructure (central log server) exists in your company (it should !)
  6. Enroll primary and secondary administrators into the wheel group and  activate this group in sudo: \
    %wheel ALL=(ALL) NOPASSWD: ALL

    Note: this is preferred method of controlling root access as linux does not have RBAC.

  7. Install writable files checking script into cron 
  8. Verify correctness of home directories permissions
  9. Populate all home directories and /root directory with .profile  and .kshrc files  (for bash users this is .bash_profile and .bashrc) and verify they are properly owned and have permissions  701
  10. ___  Important Check and if necessary disable test, guest and any other unused accounts if any were created during the installation.
  11.  ___  Modify default local security policies
  12. Verify that all users are configured using user private groups
  13. Install writable file check script into cron
  14. Configure VNC to allow remote administration
  15. Disable SSH1
  16. Verify correctness of users home directories permissions (no writable directories allowed)
  17. Enroll primary and secondary administrators into the wheel group and  activate this group in sudo: \
    %wheel ALL=(ALL) NOPASSWD: ALL

    Note: this is preferred method of controlling root access as linux does not have RBAC.

  18. Configure Sudo to allow members of the wheel group to became root
  19. Populate all home directories and /root directory with standard BASF .profile  and .kshrc files  (for bash users this is .bash_profile and .bashrc)

  20. Create baseline
    1. ___ Create the baseline of key config files for the server

      Tar /etc directory and put the tar ball

      mkdir /root/Baseline

      tar cvzf /root/Baseline/etc`date +"%Y%M%D"` /etc

      You can also use provided by Nikolai Bezroukov script.

    2. Create list of SUID, SGID and world writable files and put is into /root/Baseline
      • SUID and SGID files on your system are a potential security risk, and should be monitored closely. Because these programs grant special privileges to the user who is executing them, it is necessary to ensure that insecure programs are not installed. A favorite trick of crackers is to exploit SUID-root programs, then leave a SUID program as a back door to get in the next time, even if the original hole is plugged.

        Find all SUID/SGID programs on your system, and keep track of what they are, so you are aware of any changes which could indicate a potential intruder. Use the following command to find all SUID/SGID programs on your system:

          find / -type f \( -perm -04000 -o -perm -02000 \)
        The Debian distribution runs a job each night to determine what SUID files exist. It then compares this to the previous night's run. You can look in /var/log/setuid* for this log.

        You can remove the SUID or SGID permissions on a suspicious program with chmod, then restore them back if you absolutely feel it is necessary.

        World-writable files, particularly system files, can be a security hole if a cracker gains access to your system and modifies them. Additionally, world-writable directories are dangerous, since they allow a cracker to add or delete files as he wishes. To locate all world-writable files on your system, use the following command:
         find / -perm -2 ! -type l -ls
        and be sure you know why those files are writable. In the normal course of operation, several files will be world-writable, including some from /dev, and symbolic links, thus the ! -type l which excludes these from the previous find command.

        Unowned files may also be an indication an intruder has accessed your system. You can locate files on your system that have no owner, or belong to no group with the command:

         find / \( -nouser -o -nogroup \) -print
    3. Put ISO file from which you installed in /var/ISO directory to make possible checking and reinstallation of packages.
    4. Save content of  /boot/grub/menu.lst to /root/Baseline
  21. ___  Check and if necessary disable or delete test, guest, uucp and any other unused accounts
  22. ___ Enable firewall.
  23. Modify /etc/fstab according to Protective partitioning

    A example of "privilege minimized"  /etc/fstab from RHEL:

    LABEL=/              /              ext3 defaults                           1 1

    LABEL=/tmp           /tmp           ext3 defaults,nosuid,noexec,nodev       1 2

    LABEL=/var/log/audit /var/log/audit ext3 defaults,nosuid,noexec,nodev       1 2

    LABEL=/home          /home          ext3 defaults,nosuid,nodev              1 2

    LABEL=/var           /var           ext3 defaults,nosuid                    1 2

    LABEL=/boot          /boot          ext3 defaults,nosuid,noexec,nodev       1 2

    /tmp                 /var/tmp       ext3 defaults,bind,nosuid,noexec,nodev  1 2

    tmpfs                /dev/shm       tmpfs defaults                          0 0

    devpts               /dev/pts       devpts gid=5,mode=620                   0 0

    sysfs                /sys           sysfs defaults                          0 0

    proc                 /proc          proc defaults                           0 0

    LABEL=SWAP-sda6      swap           swap defaults                           0 0

  24. Notes



Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy


War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotesSomerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose BierceBernard Shaw : Mark Twain Quotes


Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law


Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOSProgramming Languages History : PL/1 : Simula 67 : C : History of GCC developmentScripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-MonthHow to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

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