CERIAS - Center for Education and Research in Information Assurance and Security

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An open source command-line Cassandra!


  I am pleased to announce the availability of the first beta of my_cassandra.php, which can be downloaded from my home page
(change the extension from phps to php after you download it).

Because you get the source code and the custody of your profiles, this version of Cassandra should not generate the privacy concerns that the online version did.  As it is under your control you can also run it at the intervals you choose.  It is made available under an open source license so you can modify it.  It runs under PHP so it should run on almost any platform by changing the path to PHP (from “#!/usr/bin/php -q” for MacOS X).

P.S.: I already received a patch from Benjamin Lewis from Purdue ITSP, improving robustness while reading a profile.  Thanks Ben!

Managing Web Browser risks with the NoScript extension


It is very risky to enable all client-side scripting technologies when browsing the web (plugins/ActiveX/ JavaScript/Flash etc…).  I installed the “NoScript” extension for Firefox, which allows JavaScript to run only on some whitelisted sites. It is a wonderful idea, except that it comes with a list of pre-enabled sites with some that you can’t delete (the arrogance of dictating unerasable sites!), and the defaults are to not block Flash and other plugins. Moreover, it’s only as secure as DNS, unless you require the “full addresses” option through which I presume you could require an https (SSL) url. Unfortunately there is no way to enable “base 2nd level domains” *and* require SSL, to say for example that I want to trust all *.purdue.edu sites that I contact through SSL and that have valid SSL certificates. It is better than nothing, but needs SSL support to be really useful.  Most people don’t understand the limitations and vulnerabilities of DNS, and the need for SSL, and will therefore have an unwarranted feeling of security while using this plugin.

Review: The Limits of Privacy


It has been argued that, since the 1960’s, an emphasis on individualism and personal autonomy have shaped public policy debates, including debates about the right to personal privacy.  While many scholars and advocacy groups claim that privacy is under siege, an alternate view of privacy exists, one in which it is weighed against other public interests.  In The Limits of Privacy, Amitai Etzioni espouses a communitarian approach to determining the relative value and, as the title suggests, the limits of privacy.  Privacy, the author argues, is not an absolute right, but is a right that must be carefully measured against the “common good,” which for Etzioni is defined as public health and safety.  At the heart of this book is the question of if and when we are justified in implementing measures that diminish privacy in the service of the common good.

To answer this question and to identify criteria for evaluating the relative trade-offs between privacy and the common good, Etzioni examines several examples in which privacy, depicted as an individual right, is in conflict with societal responsibilities.  Five public policy issues—namely the HIV testing of newborn babies, Megan’s Laws, encryption and government wiretapping, biometric national ID cards, and the privacy of medical records—are examined in detail.  Through his analysis, Etzioni attempts to prove that, in most cases, champions of privacy have actually done more harm than good by stifling innovation and curbing necessary democratic discussions about privacy.  A notable exception is in the case of personal medical records:  The author notes that, while “Big Brother” is normally associated with privacy violation, in the case of medical records, unregulated private industry, which Etzioni aptly coins “Big Bucks,” is a pertinent and immediate threat.

Etzioni’s analysis, while flawed in several respects (e.g. Etzioni largely ignores evidence suggesting that national IDs will do more harm than good from a security perspective), results in four criteria that can be used in examining the tension between liberty and the public interest, or in this case privacy and public health and safety.  The four criteria are as follows:

  • First, society should take steps to limit privacy only if it faces a “well-documented and macroscopic threat” to the common good;
  • second that society should identify and try any and all means that do not endanger privacy before restricting privacy;
  • third, that privacy intrusions should have minimal impact;
  • and fourth, that the undesirable side effects of privacy violations for the common good are treated (i.e. if a patient’s medical record must be digitized and shared, the confidentiality of the record must be guaranteed).

The Limits of Privacy is necessary reading for anyone involved in accepting, shaping, debating, and enacting privacy policies, both at the organizational and public-policy level.  While many readers, including this reviewer, disagree with many of Etzioni’s proposed solutions to the problems he examines, his four criteria are useful for anyone attempting to understand the intricacies involved.  Likewise, while Etzioni’s views are contrary to many of his peers, whose arguments he credits in his analysis, his arguments for justifiable invasions of privacy are a useful foil for privacy advocates and a useful reminder that privacy issues will always present real and costly trade-offs.

About:  Backtracking Intrusions


King and Chen (2005) write about their BackTracker software.  The idea is interesting:  let’s log everything needed to relate a sequence of events leading to an intrusion.  Everything in this case is processes, files, and filenames.  It can generate dependency graphs, once an anomalous process or event has been identified.  That is, something else must raise an alert, and then BackTracker helps find the cause.  It’s an interesting representation of an attack.

Taken one step further than they do, perhaps these dependency graphs could be used for intrusion detection?

About: Secure Program Execution via Dynamic Information Flow Tracking


Suh et al. (2004) propose a wonderful method for tracking taintedness, and denying dangerous operations.  It’s elegant, easy to understand, cheap in terms of performance hit, and effective.  The only problem is…  it would require re-designing the hardware (CPUs) to support it. 

I wish it would happen, but I’m not holding my breath.  Perhaps virtual machines could help until it happens, and even make it happen?