Denial of Service

Twitter Attack: Whodunit and How? Whonose?

Speculation abounds over who was responsible for the DDoS attacks that affected Twitter–and to a lesser degree, Facebook and LiveJournal–this past Thursday.

Various sources, including CNN and CNet, suggest that a Georgian blogger with accounts under the name “Cyxymu” (a town in the Republic of Georgia) on the services was targeted. The date of the attack coincides with the one year anniversary of the Russia-Georgia conflict.

Other sources, including The Register suggest that a JoeJob was the main source of the attack.  Joejobs are spam messages designed to induce someone to click on a link in the hopes that enough people will do so, thereby harming the site being linked to.

Still others blame a conventional DDoS attack using botnets, but Arbor Networks‘ analysis actually shows a drop in traffic volume hitting Twitter during the alleged DDoS attack, leaving doubt that this method was used.

I’ve also seen reports blaming hackers angry at Twitter for becoming more popular than IRC, a vigilante trying to point up the danger of botnets, and cyber-terrorists.

Seems no one really knows for sure at this point.

Twitter Hit with DDoS Attack

On Thursday morning, I decided to check my Twitter account and was greeted by a “Network Timeout” error. I tried several more times and finally gave up, thinking I’d just try later. I thought nothing more about it until I heard the news item on a local radio station that Twitter had been DDoS’d. This was confirmed at http://status.twitter.com:

Ongoing denial-of-service attack

We are defending against a denial-of-service attack, and will update status again shortly.

Update: the site is back up, but we are continuing to defend against and recover from this attack.

Update (9:46a): As we recover, users will experience some longer load times and slowness. This includes timeouts to API clients. We’re working to get back to 100% as quickly as we can.

Update (4:14p): Site latency has continued to improve, however some web requests continue to fail. This means that some people may be unable to post or follow from the website.

As of late yesterday morning communication with the API and SMS was still down.

As usual, there always seems to be some humor in these situations. Here’s a comment by John Pescatore of SANS Institute from the SANS News Bites:

[Editor's Note (Pescatore): Wow, 2 hours without tweets! That's like a
car drive to the shore without anyone in the back seat saying "Are we
there yet? I see a rock. Is that a seagull? I like saltwater taffy.
Shaquille Oneal is really tall. Are we there yet?" the entire trip.]

Firefox 3.0.7 Released, Addresses Multiple Vulnerabilities

Mozilla Foundation released Firefox 3.0.7 today to address multiple vulnerabilities. According to the Security Advisories, the vulnerabilities may allow an attacker to execute arbitrary code, cause a denial-of-service condition, obtain sensitive information, or spoof the location bar. Mozilla says that the vulnerabilities also affect Thunderbird and SeaMonkey. No updates have been released for these applications at this time.

The following Security Advisories are addressed in Firefox 3.0.7:

• Mozilla Foundation Security Advisory 2009-07: “Mozilla developers identified and fixed several stability bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these crashes showed evidence of memory corruption under certain circumstances and we presume that with enough effort at least some of these could be exploited to run arbitrary code.”
• Mozilla Foundation Security Advisory 2009-08: “An anonymous researcher, via TippingPoint’s Zero Day Initiative program, reported a vulnerability in Mozilla’s garbage collection process. The vulnerability was caused by improper memory management of a set of cloned XUL DOM elements which were linked as a parent and child. After reloading the browser on a page with such linked elements, the browser would crash when attempting to access an object which was already destroyed. An attacker could use this crash to run arbitrary code on the victim’s computer.”
• Mozilla Foundation Security Advisory 2009-09: “Mozilla security researcher Georgi Guninski reported that a website could use nsIRDFService and a cross-domain redirect to steal arbitrary XML data from another domain, a violation of the same-origin policy. This vulnerability could be used by a malicious website to steal private data from users authenticated to the redirected website.”
• Mozilla Foundation Security Advisory 2009-10: “libpng maintainer Glenn Randers-Pehrson reported several memory safety hazards in PNG libraries used by Mozilla. These vulnerabilities could be used by a malicious website to crash a victim’s browser and potentially execute arbitrary code on their computer. libpng was upgraded to a version which contained fixes for these flaws.”
• Mozilla Foundation Security Advisory 2009-11: “Mozilla contributor Masahiro Yamada reported that certain invisible control characters were being decoded when displayed in the location bar, resulting in fewer visible characters than were present in the actual location. An attacker could use this vulnerability to spoof the location bar and display a misleading URL for their malicious web page.”

Everyone should immediately upgrade to Firefox 3.0.7 to mitigate these issues.

TCP Vulnerable To Low-bandwidth DoS Attack

There’s already a frenzy of speculation, analysis and, probably, development of malware surrounding the announcement of SockStress–the proof-of-concept program developed by two Dutch researchers to exploit an apparently heretofore unknown vulnerability in the TCP/IP stack. It started when they let the cat out of the bag in an interview that got the attention of Slashdot. I’m not going to dive in and add my opinion to the frenzy; however, this incident reinforces the idea that data and network security require constant vigilance and attention to protecting the data first (See The #1 Security Priority: Protect The Information).

Steve Gibson of Gibson Research Corporation presents a good sampling of the news surrounding this issue. There’s a lot that is (and isn’t) being said. The bottom line is that it’s a nasty vulnerability. It’ll be interesting to see how this develops.