Last week was a very frustrating time for me. For whatever reason, an unusually number of botnets decided to zero in on my Drupal site and created what I call an unintentional  Denial of Service attack (DOS). The attack was actually from spambots looking looking for script vulnerabilities found mainly in older versions of e107 and WordPress. Since the target of these spambots were non-Drupal pages, my Drupal site responded by delivering an unusually large number of "page not found" and "access denied" error pages. Eventually, these requests from a multitude of IPs were too many for my server to handle and for all intents and purposes the botnet attack caused a distributed denial of service that prevented me and my users from accessing the site.

These type of attacks on Drupal sites are nothing new and have been observed and discussed at great length at Drupal.org. However, my search at Drupal.org as well as Google didn't really find a solution that completely addressed my problem. Trying to prevent a DDoS attack isn't easy to begin with and at first the answers alluded me.

I originally looked at Drupal for the solution to my problems. While I've used Mollom for months, Mollom is designed to fight off comment spam while the bots attacking my sight were looking for script vulnerabilities that didn't exist. So with Mollom being the wrong tool to fight off this kind of attack, I decided to take a look at the Drupal contributed model Bad Behavior. Bad Behavior is a set of PHP scripts which prevents spambots from accessing your site by analyzing their actual HTTP requests and comparing them to profiles from known spambots then blocks such access and logs their attempts. I actually installed an "unofficial" version of the Bad Behavior module which packages the Bad Behavior 2.1 scripts and utilizes services from Project Honey Pot.

As I had already suspected, looking for Drupal to solve this botnet attack wasn't the answer. Pretty much all Bad Behavior did for me was to take the time Drupal was spending delivering "page not found" error pages and use it to deliver "access denied" error pages. My Drupal site is likely safer with the Bad Behavior module installed, but it was the wrong tool to help me reduce the botnets from overtaxing Drupal running on my server. Ideally, you would like to prevent the attacks ever reaching your server by taking a look at such things as the firewall, router, and switches. However, since I didn't have access to the hardware, I decided it was time to look at my Apache configuration.

I felt fear, awe, and even some admiration when I read at CNET about the latest social engineering attack dreamed up by those ingenious Russian hackers.

Those entering online dating forums risk having more than their hearts stolen.

A program that can mimic online flirtation and then extract personal
information from its unsuspecting conversation partners is making the
rounds in Russian chat forums, according to security software firm PC Tools.

The artificial intelligence of CyberLover's automated chats is good
enough that victims have a tough time distinguishing the "bot" from a
real potential suitor, PC Tools said. The software can work quickly
too, establishing up to 10 relationships in 30 minutes, PC Tools said.
It compiles a report on every person it meets complete with name,
contact information, and photos.

Then again, there is one particular flaw when it comes to pulling identifiable information in an online dating forum. The flaw? It's a dating forum. I fear that this bot may find out that I'm a CEO of a multi-billion dollar company who likes to fly to the coast on weekends so I can sail one of my many yachts. Oh, I'm also still in my 20s, a chick magnet, and a full head of hair remains on top. Hopefully, the bots will not find this truthful information about me. Hmm, the feelings of fear, awe, and admiration I once felt for these hackers aren't so strong afterall.

The November 20, 2006 article "Spam surge linked to hackers" from eWeeks is a must read. Unfortunately, I can't find the actual online version of the article in print. I did however find a variant of the article posted as Pump and dump spam surge linked to Russian Bot Herders.

The article discusses the increasing complexity hackers are using botnets running on tens of thousands of hijacked Windows computers to spread spam. The article focuses on the research by SecureWorks regarding the malware trojan called Troj/SpamThru. Some scary unique features have been identified with this trojan including:

• Peer to Peer Communication (hackers can have control without a server)
• Anti-Virus Scanning (Uses anti-virus software to scan against rivals)
• Template-based spam
• Almost half of the PCs infected are PCs with Windows XP SP2 installed (outside of Vista, Microsoft's most secure Windows system to date).

Do I bring this up because I don't like Microsoft products? Not at all and in fact as I write this post I'm using a Windows XP system. My point is that if you plan on using Windows XP do all of us a favor and be sure you've installed on your PC the latest software updates and security patches available.

"Now, there is a general feeling of hopelessness among security professionals involved in finding and disabling botnets. It remains to be seen how this despair affects security products and the attitudes of the technology executives who rely on them.

'We've known about [the threat from] botnets for a few years, but we're only now figuring out how they really work, and I'm afraid we might be two to three years behind in terms of response mechanisms,' said Marcus Sachs, a deputy director in the Computer Science Laboratory of SRI International, in Arlington, Va."

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