|May the source be with you, but remember the KISS principle ;-)|
|Contents||Bulletin||Scripting in shell and Perl||Network troubleshooting||History||Humor|
|Recommended Books||UID policy||Authentication||
|Root Account||Root Security||System Accounts||Nobody Account||Dormant accounts||Security Warning Banner||NFS Security|
|SUID and SGID files||RPM-based integrity checking||Admin Horror Stories||Unix History||Humor||Etc|
The less the number of accounts the less chances that something will going on undetected. That means that it make sense to delete redundant accounts and groups.
At the same time please be aware that there is a lot of stupid security advice about account security on the Web. Be selective and understand what are you doing. Excessive zeal can lead to making user life more difficult that it should and prompt them for finding workarounds. And usually that are very inventive in this activity...
Also for existing account there should be a set of rules as for permissions and scripts running to verify that those rules are followed. One useful precaution is to remove SUID privileges from the filesystem that holds /home directory.
The same is applicable to /tmp.
See some useful (although outdated) recommendations can be found in Practical UNIX & Internet Security, 2nd Edition Appendix A
Chapter 8: Defending Your Accounts
Unix System Security Checklist
The following is a partial checklist of actions that can be taken to improve security of your Unix system. This list is neither complete, nor can all of the steps be taken on a given system.
It is not sufficient to just go through this list once, as many of these things will change over time. You should periodically "audit" your network, or install tools that will automatically monitor some aspects of system security and notify you of anything that is discovered. Even then, there is still the potential for successful attacks (through modems or any network or terminal connections). You should never consider your systems 99.999% safe unless there is no way to get in besides the keyboard at the console (to be 100% safe, you must also remove the power supply!)
- Account Security
- Inform users of "good" password selection criteria, and use either a pro-active password checker or a password cracking program to verify that passwords are secure (e.g., ftp://sable.ox.ac.uk/pub/comp/security/software/crackers/)
- If desired, and your system supports it, implement a password generator which generates "good" passwords (avoid being too clear about how the program works, since this simplifies writing attack programs)
- If desired, and your system supports it, implement password aging
- If your system supports it, implement a shadow password file (e.g., Shadow from ftp://ftp.cs.widener.edu/pub/src/adm/)
- Place expiration dates on, and periodically "expire", all accounts to eliminate unused accounts
- Carefully restrict guest accounts, using restricted shells if possible
- Do not leave "idle" (i.e. unused) guest accounts enabled
- Password protect all well-known accounts that must be on the system; delete well-known accounts that are not needed
- Make sure all accounts have passwords or "*" in the password field
- Eliminate group and shared accounts, replacing them with groups instead
- Avoid placing the current directory (".") in your (especially root's) search path
- Make sure default file protections for newly created files do not allow group/world read/write access by using a "umask" value of 022, 027, or 077, especially on the root account
- Codify rules and policies for operating as the "super user"; use "su -" instead of logging in as root to monitor use of the root account--then monitor the log files to see when this account is used
- Write-protect the "root" account's startup files and home directory
- Disable message permission using the mesg command if you are using a terminal with block-mode transmission features or remotely programmable function keys
- Minimize the number of accounts on servers and "critical" hosts
- Minimize the number of users with "super user" privileges
- Check account security with a tool like COPS or Tiger
Unix security - Wikipedia, the free encyclopedia
Chapter 3 Computer System Security and Access Controls
Web Security, Privacy & Commerce, 2nd Edition Chapter 8 The Web's War on Your Privacy
You should also visit the CERT web site. There you will find :
FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of environmental, political, human rights, economic, democracy, scientific, and social justice issues, etc. We believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit exclusivly for research and educational purposes. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner.
ABUSE: IPs or network segments from which we detect a stream of probes might be blocked for no less then 90 days. Multiple types of probes increase this period.
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 quotes : Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce : Bernard 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 DOS : Programming Languages History : PL/1 : Simula 67 : C : History of GCC development : Scripting 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
The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month : How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Haterís 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
Copyright © 1996-2016 by Dr. Nikolai Bezroukov. www.softpanorama.org was created as a service to the UN Sustainable Development Networking Programme (SDNP) in the author free time. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License.
Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.
FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.
This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...
|You can use PayPal to make a contribution, supporting development of this site and speed up access. In case softpanorama.org is down you can use the at softpanorama.info|
The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the author present and former employers, SDNP or any other organization the author may be associated with. We do not warrant the correctness of the information provided or its fitness for any purpose.
Last modified: October, 20, 2015