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... more»

DNSSEC: Once More, With Feeling!

After looking at the state of DNSSEC in some detail a little over a year ago in 2006, I've been intending to come back to DNSSEC to see if anything has changed, for better or worse, in the intervening period... To recap, DNSSEC is an approach to adding some "security" into the DNS. The underlying motivation here is that the DNS represents a rather obvious gaping hole in the overall security picture of the Internet, although it is by no means the only rather significant vulnerability in the entire system. One of the more effective methods of a convert attack in this space is to attack at the level of the DNS by inserting fake responses in place of the actual DNS response. more»

Attack Seriously Slows Two Internet Root Servers

Online attackers have briefly disrupted service on at least two of the 13 "root" servers that are used to direct traffic on the Internet.

The attack, which began Tuesday at about 5:30 a.m. Eastern time, was the most significant attack against the root servers since an October 2002 distributed denial of service (DDOS) attack, said Ben Petro, senior vice president of services with Internet service provider Neustar Inc. more»

Domain Registrars Releasing Suspended Domains to Attackers

Mary Landesman of ScanSafe reports: "A new outbreak of SQL attacks began on the 8th. Not that they ever really go away, but new waves replace the old ones. The attackers are using a much larger number of domains than seen in previous months. Just 11 days into June, and already 54 of these domains have been observed. Many of these are previously suspended domains that registrars have released back to the attackers. more»

Where are DNS Root Servers? See them on Google Maps

DNS root servers function as part of the Internet backbone, as explained in Wikipedia, and have come under attack a number of times in the past -- although none of the attacks have ever been serious enough to severely hamper the performance of the Internet. In response to some of the common misconceptions about the physical location and total number of DNS root servers in the world, Patrik Faltstrom has put together a visual map on Google, pin-pointing the approximate location of each server around the world. more»

Time to Play Offense

The United States is under cyber-attack. An article in Time magazine titled "The Invasion of the Chinese Cyberspies" discusses a computer-network security official for Sandia National Laboratories who had been "tirelessly pursuing a group of suspected Chinese cyberspies all over the world." The article notes that the cyberespionage ring, known to US investigators as Titan Rain, has been "penetrating secure computer networks at the country's most sensitive military bases, defense contractors and aerospace companies." 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»

Possible First Attacks on DNS Flaw Have Been Reported

The existence of the DNS flaw was revealed earlier this month by security researcher Dan Kaminsky and the code that could act as a blueprint for an attack via the flaw was published last week by Metasploit. On Friday, a user named James Kosin posted an excerpt from a server log to a Fedora Linux mailing list, claiming it proved attacks based on the DNS flaw had begun. Kosin post reads... more»

Do We Need Two Internets?

Jonathan Zittrain's recent book, The Future of the Internet -- And How to Stop It, has spurred a lot of discussion both online and offline, with blog posts lauding his insights or criticising his over-apocalyptic imagination. The book itself makes fascinating reading for those who have watched the network grow from its roots in the research community into today's global channel for communications, commerce and cultural expression... One of the reasons that Zittrain puts forward for the growing popularity of closed or, as he prefers 'tethered', devices, is that they are less vulnerable to hacking, security flaws, malware and all the other perils that face any internet-enabled system. more»

Are Botnets Run by Spy Agencies?

A recent story today about discussions for an official defense Botnet in the USA prompted me to post a question I've been asking for the last year. Are some of the world's botnets secretly run by intelligence agencies, and if not, why not? Some estimates suggest that up to 1/3 of PCs are secretly part of a botnet. The main use of botnets is sending spam, but they are also used for DDOS extortion attacks and presumably other nasty things like identity theft. But consider this... more»

Report on DNS Amplification Attacks

In this newly released paper Randal Vaughn and Gadi Evron discuss the threat of Distributed Denial of Service (DDoS) attacks using recursive DNS name servers open to the world. The study is based on case studies of several attacked ISPs reported to have on a volume of 2.8Gbps. One reported event indicated attacks reaching as high as 10Gbps and used as many as 140,000 exploited name servers. more»

So You Think You're Safe from DNS Cache Poisoning?

Everyone is probably well aware of the Kashpureff-style DNS cache- poisoning exploit (I'll call this "classic cache poisoning"). For reference, see the original US-CERT advisory prompted by this exploit. Vendors patched their code to appropriately scrub (validate) responses so that caches could not be poisoned. For the next 7-8 years, we didn't hear much about cache poisoning. However, there was still a vulnerability lurking in the code, directly related to cache poisoning. ...On April 7, 2005, the SANS ISC (not to be confused with Internet Systems Consortium) posted an update detailing how Microsoft Windows DNS servers were still being poisoned, even though the "Secure cache against pollution" option was set. The SANS ISC found that Windows DNS servers using BIND4 and BIND8 servers as forwarders were being poisoned. But how could this be? more»

Protecting the Internet: Certified Attachments and Reverse Firewalls?

In many respects the internet is going to hell in a hand basket. Spam, phishing, DNS poisoning, DDoS attacks, viruses, worms, and the like make the net a sick place. It is bad enough that bad folks are doing this. But it is worse that just about every user computer on the net offers a nice fertile place for such ill behavior to be secretly planted and operated as a zombie under the control of a distant and unknown zombie farmer. ...Some of us are coming to the converse point of view that the net is being endangered by the masses of ill-protected machines operated by users. more»

Security by Obscurity?

Ah yes, 'Security by obscurity': "Many people believe that 'security through obscurity' is flawed because... secrets are hard to keep." I'm glad the guys guarding the A Root Servers are up on the latest security trends. Of course, you could hide the A Root Servers at the heart of the Minotaur's maze, but they're still going to be "right over there" in cyberspace, at 198.41.0.29 more»

Revision3 and Media Defender

Lots of coverage in the last two days about a Memorial Day weekend attack that took down the servers of Revision3, an Internet video network. This story has a lot of ingredients -- P2P maneuvering, DDoS attack, copyright vs. piracy, talk of laws broken and the FBI investigating. What's the CircleID take? Revision3's description. more»