Secure Programmer: Minimizing Privileges

By David A. Wheeler
2005-05-27


Resources

• Read David's other Secure programmer columns on developerWorks.
  
  
• David's book Secure Programming for Linux and Unix HOWTO (Wheeler, 3 March 2003) gives a detailed account on how to develop secure software.
  
  
• "Internet Security Systems Security Advisory: Remote Sendmail Header Processing Vulnerability" (March 3, 2003) gives a technical overview of the Sendmail vulnerability mentioned in this article.
  
  
• "CERT(R) Advisory CA-2003-07 Remote Buffer Overflow in Sendmail" (March 3, 2003, revised June 09, 2003) also discusses the Sendmail vulnerability.
  
  
• "Postfix: A Secure and Easy-to-Use MTA" by Glenn Graham (OnLamp.Com, 8/21/2003) describes Postfix from an administrator's point of view.
  
  
• "Postfix Overview - Security" gives an overview of Postfix's security approach.
  
  
• "Postfix Anatomy - Receiving Mail" begins a description of Postfix's design, including how the program is divided up to support minimizing privileges.
  
  
• "The Protection of Information in Computing Systems" in Proceedings of the IEEE by J. Saltzer and M. Schroeder is a classic paper on the basic principles in developing secure programs (September 1975, v63 n9, pp. 1278-1308). It's amazing how applicable it still is today.
  
  
• The Single UNIX Specification version 3, also known as The Open Group Base Specifications Issue 6 and IEEE Std 1003.1, 2003 Edition, specify what a "UNIX-like" system must do.
  
  
• Secure Programming Cookbook by John Viega and Matt Messier (O'Reilly & Associates, 2003) has some useful code snippets showing how to drop privileges on UNIX-like systems.
  
  
• "Greetings" by Crispin Cowan describes the initial goals of the Linux Security Modules (LSM) project, and includes a lengthy pair of emails by Linus Torvalds that set the parameters for the effort.
  
  
• "NT Religious Wars: Why Are DARPA Researchers Afraid of Windows NT?" is an interesting article because it found that, in spite of strong pressure by paying customers, computer science researchers strongly resisted basing research on the proprietary Windows operating system. This article helps to explain why so many research efforts, including NSA's, decided to use the Linux or *BSD kernels as the basis for security research instead.
  
  
• This OnLamp.com article on FreeBSD Jails has more information on jail().
  
  
• The Linux Security Modules Home Page has a number of useful articles about the LSM framework.
  
  
• "Linux Security Modules: General Security Support for the Linux Kernel" provides an excellent overview of how the LSM works. It has many authors, because of the many different groups working together to create a general framework.
  
  
• The Security-Enhanced Linux (SELinux) Web site has lots of information about SELinux.
  
  
• Learn more about Mandatory Access Control and other open systems security issues at the National Institute of Standards and Technology (NIST).
  
  
• IBM Research Security group has a number of security-related projects, including Internet security, Java security, cryptography, and data hiding.
  
  
• Find more resources for Linux developers in the developerWorks Linux zone.
  
  
• Purchase Linux books at discounted prices in the Linux section of the Developer Bookstore.
  
  
• Develop and test your Linux applications using the latest IBM tools and middleware with a developerWorks Subscription: you get IBM software from WebSphere, DB2, Lotus, Rational, and Tivoli, and a license to use the software for 12 months, all for less money than you might think.
  
  
• Download no-charge trial versions of selected developerWorks Subscription products that run on Linux, including WebSphere Studio Site Developer, WebSphere SDK for Web services, WebSphere Application Server, DB2 Universal Database Personal Developers Edition, Tivoli Access Manager, and Lotus Domino Server, from the Speed-start your Linux app section of developerWorks. For an even speedier start, help yourself to a product-by-product collection of how-to articles and tech support.
  

Tutorial Pages:
» Taking the fangs out of bugs
» Basics of minimizing privileges
» Minimize privileged modules
» Minimize privileges granted
» Minimize privileges' time
» Newer mechanisms
» Conclusions
» Resources


First published by IBM DeveloperWorks

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