Even technically sophisticated users lose perspective on security at times. We all want breaches of security to be someone elses fault and we dont want to have to deal with the inconveniences of running a secure system.
But there are certain security rules that apply to all computing platforms. These rules are expressed well in an article on Microsofts TechNet site called Microsofts Ten Immutable Laws of Security. These laws are worth keeping in the back, and often the front, of your mind.
Law No. 1: If a bad guy can persuade you to run his program on your computer, its not your computer anymore. The first law, appropriately, is the most important one. Its a truism so true that it often gets dismissed as trite when its actually at the heart of many attacks. It is at the heart of many social engineering attacks, including spyware and almost all e-mail worms, including Bagle and Netsky.
We try to mitigate this threat with such products as anti-virus software, but these can never be perfect. The primary defense must be the one typing at the keyboard, and if you are cavalier about running programs that you get from strangers you will likely end up compromising your computer.
Its only fair to say though that this is also an area in which Microsoft, for complicated reasons, shares some responsibility. The ability for a bad guy to persuade you to run a malicious program is related to your own rights on the computer; if you are running as a less-privileged user, then the program you run is limited in the damage it can do. Microsoft has good tools for limiting the rights of users in a managed corporate environment, but it hasnt made enough of an effort to do so for consumers.
Law No. 2: If a bad guy can alter the operating system on your computer, its not your computer anymore. I really hope this is obvious. Some programs on the computer must be trusted, and—significantly—I lump device drivers in this as well. Microsoft has actually put good protections into Windows against such threats with system file protection, which looks for modifications to critical system files and undoes them.
Law No. 3: If a bad guy has unrestricted physical access to your computer, its not your computer anymore. There is no security without physical security. Consider that someone alone with your computer can boot it up off the floppy or CD drive and run his or her own software while none of the software on your computer can protect it. The attacker could install spyware, compromise your own security provisions, or just wipe out the disk.
Law No. 4: If you allow a bad guy to upload programs to your Web site, its not your Web site any more. “Upload” is such an official way to put this; the real-world way this often happens is to invoke a buffer overflow on the server in order to run arbitrary code on it, but there are other ways it can happen.
Next page: Passwords and administrators.
Law No. 5: Weak passwords trump strong security. If I can guess, quickly, that your administrator password is “admin” or something else easily surmised, then Law No. 1 comes into effect because I can run whatever I want on your computer. I can do a lot of damage with just a user password as well.
Law No. 6: A computer is only as secure as the administrator is trustworthy. Microsoft uses business examples in this case to show how important it is to a business that the system administrator be trustworthy, and this is an essential point. Every consultant you hire may require administrative access and need to be trusted with the assets of your business. But its true at home, too. Are your teenagers trustworthy with your computer? Maybe they shouldnt be administrators.
Law No. 7: Encrypted data is only as secure as the decryption key. In public key cryptography there is a private key that only you should have, and its called the “private” key for a reason. If its stored on the computer, then an attacker could get access to it. The same is true of passwords. You need to memorize them or store them in a place that cant easily be compromised. This is inconvenient, but at least be aware of the vulnerability youre creating if you make passwords and encryption keys too convenient.
Law No. 8: An out-of-date virus scanner is only marginally better than no virus scanner at all. “Marginally” is a debatable way to put it. No doubt about it, its better to be up to date, but the most prevalent threats out there are quite old. If the user is not too credulous and you do update the scanner before too long, its not disastrous.
Law No. 9: Absolute anonymity isnt practical, in real life or on the Web. Much of the Web appears to be a place you can visit and interact with anonymously, but this is largely a mirage. Unless youre very careful and sophisticated, you are always leaving clues around as to who you are and how someone could track you down. This usually doesnt matter because, realistically, who cares about what Web sites youre surfing? But dont assume that you are the wind and that you can whisk in and out of sites unseen.
Law No. 10: Technology is not a panacea. Security is, unfortunately, a series of trade-offs with other goals we expect from computing, with convenience usually at the front of the list. Novices may expect security suites that claim to be comprehensive will protect them, but this can never be the whole truth.
The fact that security cant be perfect isnt a reason to criticize anyone—its just a fact of life. You cant do a perfect job, but you can do a good job, and knowing the limitations of the technology is a good place to start.
Security Center Editor Larry Seltzer has worked in and written about the computer industry since 1983.
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