Spam

Sender Address Verification: Still a Bad Idea

A lot of spam uses fake return addresses. So back around 2000 it occurred to someone that if there were a way to validate the return addresses in mail, they could reject the stuff with bad return addresses. A straightforward way to do that is a callout, doing a partial mail transaction to see if the putative sender's mail server accepts mail to that address. This approach was popular for a few years, but due to its combination of ineffectiveness and abusiveness, it's now used only by small mail systems whose managers don't know any better. What's wrong with it? more

UN Global Forum on Internet Governance

More than 200 leaders from government, business and civil society attended the Global Forum on Internet Governance, held on 25 and 26 March 2004 and organized by the United Nations Information and Communication Technologies (ICT) Task Force. The forum, held at United Nations Headquarters in New York, was intended, according to a UN press release, "to contribute to worldwide consultations to prepare the ground to a future Working Group on Internet Governance to be established by Secretary-General Kofi Annan, which is to report to the second phase of the World Summit on the Information Society (Tunis, 2005)". more

What is Anti-Spam?

There's a lot of argument as to which "anti-spam" techniques are legitimately so called. In this article, I'd like to consider what constitutes an anti-spam technique in an ideal sense, then consider the various practiced approaches to spam mitigation in that light, drawing conclusions as to how we should frame the "anti-spam" discussion. ...For the purposes of this discussion, let "spam" refer to "unsolicited bulk email". Not everyone agrees on this definition, but it's by far the most widely accepted, and without a working definition we won't be able to define "anti-spam"... more

Sender ID: A Tale of Open Standards and Corporate Greed? - Part II

While everything seemed fine and various participants in these discussions were celebrating the merger of these proposals into one, as well as the support of Microsoft in this endeavor, there was an elephant in the room so to speak, and a rather large one at that. When the original Caller-ID proposal was published, a patent license came along with it. Microsoft indicated that they were planning on filing patents on Caller-ID or some of its aspects, and offered a royalty-free license for the use of their intellectual property. There was some talk about the incompatibility of the license with open source software, including comments from Eben Moglen of FSF and Richard Stallman, but Microsoft employees assured the MARID WG that the licensing issue would be resolved in time for the San Diego meeting. Except that it wasn't.  more

A Fundamental Look at DNSSEC, Deployment, and DNS Security Extensions

In looking at the general topic of trust and the Internet, one of the more critical parts of the Internet's infrastructure that appears to be a central anchor point of trust is that of the Domain Name Service, or DNS. The mapping of "named" service points to the protocol-level address is a function that every Internet user relies upon, one way or another. The ability to corrupt the operation of the DNS is one of the more effective ways of corrupting the integrity of Internet-based applications and services. If an attacker can in some fashion alter the DNS response then a large set of attack vectors are exposed. ...The more useful question is whether it is possible to strengthen the DNS. The DNS is a query -- response application, and the critical question in terms of strengthening its function is whether it is possible to authenticate the answers provided by the DNS. DNSSEC provides an answer to this question. more

SPF Loses Mindshare

MAAWG is the Messaging Anti-Abuse Working group. It was started by Openwave, a vendor that sells e-mail hardware and software to large ISPs and originally consisted only of Openwave customers, but has evolved into an active forum in which large ISPs and software vendors exchange notes on anti-spam and other anti-abuse activities. Members now include nearly every large ISP including AOL, Earthlink, Yahoo, Comcast and Verizon is a member, along with ESPs like Doubleclick, Bigfoot, and Checkfree, and vendors like Ciscom, Ironport, Messagelabs, Kelkea/Trend, and Habeas. They've also been quietly active in codifying best practices and working on some small but useful standards like a common abuse reporting format. more

Sender ID: A Tale of Open Standards and Corporate Greed? - Part I

A long long time ago when the Internet was still young and most people were still using clunky Apples, PCs and mainframes; two documents were published by the Advanced Research Projects Agency (ARPA), part of the US Government's Department of Defense. They were called "RFC 821 - Simple Mail Transfer Protocol" and "RFC 822 - Standard for the format of ARPA Internet text messages" respectively. Written by the John Postel and Dave Crocker respectively, often referred to as some of the founding fathers of the Internet, they defined a simple text-based email system for the use of the fledging network then called the "ARPA Internet"... more

Yahoo, Gmail, Hotmail Compromised - But How?

One of the bigger news stories is that of 10,000 usernames and passwords of Hotmail users were posted this past week, victims of a phishing scam... It seems unlikely to me that this would be a hack where someone would break into Hotmail's servers and access the account information that way. It is much more likely that the spammers got the information by social engineering. Why is this more likely? For one, they'd have to get past all of the firewalls and security measures that Microsoft/Hotmail have to keep intruders out. more

Thoughts About “Protection Against BIND”

Imagine my surprise upon reading a BBC article which identified ISC BIND as the top security vulnerability to UNIX systems. At ISC, we have striven for a decade to repair BIND's reputation, and by all accounts we have made great progress. "What could this be about," I wondered, as I scanned the BBC article for more details. It turns out that BBC was merely parroting what it had been told by SANS. OK, let's see what SANS has to say... more

The Future of Some Email May Not Use Email

Paul McNamara quotes me extensively in this piece on the EFF protest of Goodmail. When I say "the EFF has lost its mind", i really mean "the EFF has lost its way". In the early days, the EFF was about preventing the government from ruining the Internet commons, and preventing the government from putting walls on the frontier. These days, the EFF is more about preventing companies who have no power to regulate from doing things the EFF doesn't like. That is a huge change, and one that makes the EFF much less worthy of support... more

Does the Internet Need to be Governed?

The term "Internet Governance" has become an area of particular attention in part as a consequence of widespread recognition that the Internet represents an important area of national interest for all countries seeking to participate in the benefits of global electronic commerce, distance learning, access to the encyclopedic wealth of information on the Internet, and in the social dimension that the Internet is creating. From the perspective of governments, the Internet is simultaneously a technology that promises high economic value for parties making use of it and a challenge in that it is unlike all other telecommunications media previously invented. more

Comments on an IP Address Trading Market

With IPv4 addresses becoming scarcer, there has been talk that a trading market will develop. The idea is that those holding addresses they do not really need will sell them for a profit. More alarming is that there have been a few articles about how the Regional Internet Registries (RIR) are contemplating creating such a market so that they can regulate it, conceding that it will happen anyway and taking the "if you can't be 'em, join 'em" attitude. This is all a bit disturbing. Maybe I'm naïve, but it's a little unclear to me how an unsanctioned trading market could really operate without the RIRs at least being aware... more

Wall Street Journal Article on Whois Privacy

Today's Wall Street Journal discusses the fight over Whois privacy. The article on the front page of the Marketplace section starts by discussing how the American Red Cross and eBay use the Whois database to track down scammers: "Last fall, in the wake of Hurricane Katrina, the American Red Cross used an Internet database called "Whois" that lists names and numbers of Web-site owners to shut down dozens of unauthorized Web sites that were soliciting money under the Red Cross logo. Online marketplace eBay Inc. says its investigators use Whois hundreds of times a day..." more

Hypertext Mail Protocol (a.k.a. Stub Email): A Proposal

Back in the days of dial-up modems and transfer speeds measured in hundreds of bits per second, unwanted email messages were actually felt as a significant dent in our personal pocketbooks. As increases in transfer speeds outpaced increases in spam traffic, the hundreds of unwanted emails we received per week became more of a nuisance than a serious financial threat. Today sophisticated spam filters offered by all major email providers keep us from seeing hundreds of unwanted emails on a daily basis, and relatively infrequently allow unwanted messages to reach our coveted Inboxes. So, to some degree, the spam problem has been mitigated. But this "mitigation" requires multiple layers of protection and enormous amounts of continually-applied effort. more

DNS Firewalls In Action - RPZ vs. Spam

In general, a network firewall is just a traffic filter... Filtering rules can be anything from "allow my web server to hear and answer web requests but not other kinds of requests" to "let my users Ping the outside world but do not let outsiders Ping anything on my network." The Internet industry has used firewalls since the mid-1980's and there are now many kinds, from packet layer firewalls to web firewalls to e-mail firewalls. Recently the DNS industry has explored the firewall idea and the results have been quite compelling. In this article I'm going to demonstrate a DNS firewall built using RPZ (Response Policy Zones) and show its potential impact on e-mail "spam". more