Threat Intelligence

Port 25 Blocking, or Fix SMTP and Leave Port 25 Alone for the Sake of Spam?

Larry Seltzer wrote an interesting article for eWeek, on port 25 blocking, the reasons why it was being advocated, and how it would stop spam. This quoted an excellent paper by Joe St.Sauver, that raised several technically valid and true corollaries that have to be kept in mind when blocking port 25 -- "cough syrup for lung cancer" would be a key phrase... Now, George Ou has just posted an article on ZDNET that disagrees with Larry's article, makes several points that are commonly cited when criticizing port 25 blocking, but then puts forward the astonishing, and completely wrong, suggestion, that worldwide SPF records are going to be a cure all for this problem. Here is my reply to him...

What is ‘Pharming’ and Should You Be Worried?

The sky is falling! The sky is falling! ...or is it? What is this thing called "pharming"? Put simply, it's redirection of web traffic, so that the server you think you're talking to actually belongs to a criminal. For example: you think you're talking to www.examplebank.com because it says so in the browser's address bar, but actually you're connected to www.mafia-R-us.ru. This can happen in three main ways: 1. DNS Hijack: a social engineering attack on the Internet infrastructure...

History of SMTP

The following excerpt is from the Free Software Magazine, March 2005 Issue, written by Kirk Strauser. To read the entire article, you may download the magazine here [PDF]. Also thanks to Yakov Shafranovich for making us aware of this publication. "Spam has existed since at least 1978, when an eager DEC sales representative sent an announcement of a product demonstration to a couple hundred recipients. The resulting outcry was sufficient to dissuade most users from repeating the experiment. This changed in the late 1990s: millions of individuals discovered the internet and signed up for inexpensive personal accounts and advertisers found a large and willing audience in this new medium."

CENTR Statement on IDN Homograph Attacks

Recently a proof of concept attack was announced on the Internet that demonstrated how a web address could be constructed that looked in some web browsers identical to that of a well known website. This technique could be used to trick a user into going to a website that they did not plan on visiting, and possibly provide sensitive information to a third party. As a result of this demonstration, there has been a number of voices calling for web browsers to disable or remove support for IDNs by default. ...CENTR, a group of many of the world's domain registries - representing over 98% of domain registrations worldwide - believes such strong reactions are heavily detrimental...

IDN Spoofing Solutions With Balance

Last week's tizzy about IDN (Internationalized Domain Name) spoofing was an interesting exercise in watching how people react to the unknown. The nearly-universal response to the problem that had been described in detail many years ago was "turn off IDNs" instead of "assume that the people who created IDNs knew about this, so let's do some research." The following is based on my thoughts this week. For those of you who are not familiar with my earlier work, I'm one of the authors of the IDN standards...

IDN and Homographs Spoofing

There is a published spoofing attack using homographs IDN. By using a Cyrillic SMALL LETTER A (U+430), Securnia is able to pretend to be http://www.paypal.com/. Actually this is well-documented in RFC 3490 under the Security Consideration: "To help prevent confusion between characters that are visually similar, it is suggested that implementations provide visual indications where a domain name contains multiple scripts. Such mechanisms can also be used to show when a name contains a mixture of simplified and traditional Chinese characters, or to distinguish zero and one from O and l..."

How to Stop Spam

I got a letter the other day from AOL postmaster Carl Hutzler, about how the Internet community could get rid of spam, if it really wanted to. With his permission, here are some excerpts. "Spam is a completely solvable problem. And it does not take finding every Richter, Jaynes, Bridger, etc to do it (although it certainly is part of the solution). In fact it does not take email identity technologies either (although these are certainly needed and part of the solution)."

Survey Predicts Attacks on the Network Infrastructure Within 10 Years

Pew Internet Project has released a report called "The Future of the Internet" based on a recently conducted survey where 1,286 internet experts are said to have looked at the future impact of the internet and assessed predictions about how technology and society will unfold. The following is and excerpt from the report predicting at least one devastating attack will occur in the next 10 years on the networked information infrastructure or the United States power grid.

Person to Person Security and Privacy Infringement

IT security strategies invariably focus on maintaining impenetrable fortresses around computers and network systems. Firewalls, virtual private networks and anti-virus programs are the tools IT engineers use to create their digital security. Sophisticated defense systems can be very effective at keeping the obvious attackers at bay, yet they often create a false sense of security because the real attacks, the kind that inflict irreparable damage on a system or network, avoid the obvious routes into the secure fortress.

2004: The Year That Promised Email Authentication

As the year comes to a close, it is important to reflect on what has been one of the major actions in the anti-spam arena this year: the quest for email authentication. With email often called the "killer app" of the Internet, it is important to reflect on any major changes proposed, or implemented that can affect that basic tool that many of us have become to rely on in our daily lives. And, while many of the debates involved myriads of specialized mailing lists, standards organizations, conferences and even some government agencies, it is important for the free and open source software (FOSS) community as well as the Internet community at large, to analyze and learn lessons from the events surrounding email authentication in 2004.