Strong Passwords

By Larry Seltzer  |  Posted 2004-06-21 Print this article Print

Its the future of mail worms, and in fact the only future for mail worms. Theyre going to have to authenticate someday, so they will either need to use open relays or scam the user out of their own SMTP AUTH credentials. SMTP AUTH is the authentication scheme for end-user SMTP server access. Most ISPs require that you provide a username and password to send as well as to retrieve mail, and eventually all of them will.

Ive read stories about worms attempting to send mail on authenticated SMTP servers by guessing weak passwords. Simply by scraping e-mail addresses, you can guess the usernames (foo is the username for
If the system doesnt force you to choose a strong password, many users will try "foo" or "password" or "asdf" or "comcast" or something else really easy. Weak SMTP AUTH credentials are an understudied problem and will come to the forefront in the next year or two for this reason.
I checked with a couple of network security scanners, and neither of them look for weak SMTP AUTH credentials. With an open scanner such as Nessus, it should be possible to write a plug-in that does the test.

For insights on security coverage around the Web, check out Security Center Editor Larry Seltzers Weblog. Rate limiting isnt a new idea for stopping spam. Microsofts famous Penny Black project, which attempts to make the sender pay for sending an e-mail by solving a computational problem that takes a fixed amount of time, is a roundabout way of implementing rate limiting. Why not just rate limit? The Penny Black argument would be—I guess—that a recipient can rate limit the sender rather than relying on infrastructure-based rate limiting. Personally, I think theres a much better chance of major changes happening on the server end than on the client end.

Time to wake up and smell the limits. Consumer broadband accounts that provide happy hunting grounds for zombie programs will need to be restricted in their freedom to e-mail willy-nilly. Its too bad, but its not going to affect the overwhelming majority of users who have no need to send mail other than through their ISPs mail servers, and no need to send even 100 messages a day, let alone thousands.

Security Center Editor Larry Seltzer has worked in and written about the computer industry since 1983. Check out eWEEK.coms Security Center at for the latest security news, reviews and analysis.

Be sure to add our developer and Web services news feed to your RSS newsreader or My Yahoo page More from Larry Seltzer

Larry Seltzer has been writing software for and English about computers ever since—,much to his own amazement—,he graduated from the University of Pennsylvania in 1983.

He was one of the authors of NPL and NPL-R, fourth-generation languages for microcomputers by the now-defunct DeskTop Software Corporation. (Larry is sad to find absolutely no hits on any of these +products on Google.) His work at Desktop Software included programming the UCSD p-System, a virtual machine-based operating system with portable binaries that pre-dated Java by more than 10 years.

For several years, he wrote corporate software for Mathematica Policy Research (they're still in business!) and Chase Econometrics (not so lucky) before being forcibly thrown into the consulting market. He bummed around the Philadelphia consulting and contract-programming scenes for a year or two before taking a job at NSTL (National Software Testing Labs) developing product tests and managing contract testing for the computer industry, governments and publication.

In 1991 Larry moved to Massachusetts to become Technical Director of PC Week Labs (now eWeek Labs). He moved within Ziff Davis to New York in 1994 to run testing at Windows Sources. In 1995, he became Technical Director for Internet product testing at PC Magazine and stayed there till 1998.

Since then, he has been writing for numerous other publications, including Fortune Small Business, Windows 2000 Magazine (now Windows and .NET Magazine), ZDNet and Sam Whitmore's Media Survey.

Submit a Comment

Loading Comments...
Manage your Newsletters: Login   Register My Newsletters

Rocket Fuel