|By Lori MacVittie||
|April 15, 2013 10:30 AM EDT||
DNS, like any public service, is vulnerable. Not in the sense that it has vulnerabilities but vulnerable in the sense that it must, by its nature and purpose, be publicly available. It can't hide behind access control lists or other traditional security mechanisms because the whole point of DNS is to provide a way to find your corporate presence in all its digital forms.
It should therefore not come as a surprise that eventually it turned up in the news as the primary player in a global and quite disruptive DDoS attack.
The gory details, most of which have already been circulated, are nonetheless fascinating given the low technological investment required. You can duplicate the effort with about 30 friends each with a 30Mbps connection (that means I'm out, sorry). As those who've been in the security realm for a while know, that's because these types of attacks require very little on the attack side; the desired effects come due to the unbalanced request-response ratio inherent in many protocols, DNS being one of them.
In the world of security taxonomies these are called "amplification" attacks. They aren't new; "Smurf attacks" (which exploited ICMP) were first seen in the 1990s and effected their disruption by taking advantage of broadcast addresses. DNS amplification works on the same premise, because queries are small but responses tend to be large. Both ICMP and DNS amplification attacks are effective because they use UDP, which does not require a handshake and is entirely uninterested in verifying whether or not the IP address in the request is the one from which the the request was received. It's ripe for spoofing with much less work than a connection-oriented protocol such as TCP.
To understand just how unbalanced the request-response ratio was in this attack, consider that the request was: “dig ANY ripe.net @ <OpenDNSResolverIP> +edns0=0 +bufsize=4096”. That's 36 bytes. The responses are typically 3K bytes, for an amplification factor of 100. There were 30,000 open DNS resolvers in the attack, each sending 2.5Mbps of traffic each, all directed at the target victim. CloudFlare has a great blog on the attack, I recommend a read. Another good resource on DNS amplification attacks is this white paper. Also fascinating is that this attack differed in that the target was sent a massive number of DNS responses - rather than queries - that it never solicited in the first place.
The problem is DNS is, well, public. Restricting responses could ostensibly unintentionally block legitimate client resolvers causing a kind of self-imposed denial of service. That's not acceptable. Transitioning to TCP to take advantage of handshaking and thus improve the ability to detect and shut down attempted attacks would certainly work, but at the price of performance. While F5's BIG-IP DNS solutions are optimized to avoid that penalty, most DNS infrastructure isn't and that means a general slowdown of a process that's already considered "too slow" by many users, particularly those trying to navigate the Internet via a mobile device.
So it seems we're stuck with UDP and with being attacked. But that doesn't mean we have to sit back and take it. There are ways in which you can protect against the impact of such an attack as well as others lurking in the shadows.
1. DEPRECRATE REQUESTS (and CHECKING RESPONSES)
It is important to validate that the queries being sent by the clients are ones that the DNS servers are interested in answering, and are able to. A DNS firewall or other security product can be used to validate and only allow the DNS queries that the DNS server is configured for. When the DNS protocol was designed, there were a lot of features built into the protocol that are no longer valid due to the evolving nature of the Internet. This includes many DNS query types, flags available and other settings. One would be surprised at what types of parameters are available to mark on a DNS request and how they can be manipulated. For example, DNS type 17=RP, which is the Responsible Person for that record. In addition, there are ways to disrupt DNS communications by putting bad data in many of these fields. A DNS firewall is able to inspect these DNS queries and drop the requests that do not conform to DNS standards and do not use parameters that the DNS servers are configured for.
But as this attack proved, it's not just queries you have to watch out for - it's aslo responses. F5 DNS firewall features include stateful inspection of responses which means any unsolicited DNS responses are immediately dropped. While that won't change the impact on bandwidth, it will keep the server from becoming overwhelmed by processing unnecessary responses.
2. ENSURE CAPACITY
DNS query capacity is critical to delivering a resilient available DNS infrastructure. Most organizations recognize this and put into place solutions to ensure high availability and scale of DNS. Often these solutions are simply caching DNS load balancing solutions which have their own set of risks, including being vulnerable to attack using random, jabberwocky host names. Caching DNS solutions only cache responses returned from authoritative sources and thus when presented with an unknown host name, it must query the origin server. Given a high enough volume of queries, the origin servers can still be overwhelmed, regardless of the capacity of the caching intermediary.
A high performance in-memory authoritative DNS server such as F5 DNS Express (part of F5 BIG-IP Global Traffic Manager) can shield origin servers from being overwhelmed.
3. PROTECT AGAINST HIJACKING
The vulnerability of DNS to hijacking and poisoning is still very real. In 2008, a researcher, Evgeniy Polyakov, showed that it was possible to cache poison a DNS server that was patched and running current code within 10 hours. This is simply unacceptable in an Internet-driven world that relies, ultimately, on the validity and integrity of DNS. The best solution to this and other vulnerabilities which compromise the integrity of DNS information is DNSSEC. DNSSEC was introduced to specifically correct the open and trusting nature of the protocol’s original design. DNS queries and responses are signed using keys that validate that the DNS answer was not tampered with and that it came from a reliable DNS server.
F5 BIG-IP Global Traffic Manager (GTM) not only supports DNSSEC, but does so without breaking global server load balancing techniques.
As a general rule, you should verify that you aren't accidentally running an open resolver. Consider the benefits of implementing DNS with an ICSA certified and hardened solution that does not function as an open resolver, period. And yes, F5 is a good choice for that.
The 20th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held June 6-8, 2017, at the Javits Center in New York City, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Containers, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal ...
Jan. 19, 2017 01:15 PM EST Reads: 5,148
@DevOpsSummit taking place June 6-8, 2017 at Javits Center, New York City, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. @DevOpsSummit at Cloud Expo New York Call for Papers is now open.
Jan. 19, 2017 01:15 PM EST Reads: 3,514
SYS-CON Events announced today that Dataloop.IO, an innovator in cloud IT-monitoring whose products help organizations save time and money, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Dataloop.IO is an emerging software company on the cutting edge of major IT-infrastructure trends including cloud computing and microservices. The company, founded in the UK but now based in San Fran...
Jan. 19, 2017 12:45 PM EST Reads: 2,529
Synthetic monitoring is hardly a new technology. It’s been around almost as long as the commercial World Wide Web has. But the importance of monitoring the performance and availability of a web application by simulating users’ interactions with that application, from around the globe, has never been more important. We’ve seen prominent vendors in the broad APM space add this technology with new development or partnerships just in the last 18 months.
Jan. 19, 2017 12:45 PM EST Reads: 1,631
Updating DevOps to the latest production data slows down your development cycle. Probably it is due to slow, inefficient conventional storage and associated copy data management practices. In his session at @DevOpsSummit at 20th Cloud Expo, Dhiraj Sehgal, in Product and Solution at Tintri, will talk about DevOps and cloud-focused storage to update hundreds of child VMs (different flavors) with updates from a master VM in minutes, saving hours or even days in each development cycle. He will also...
Jan. 19, 2017 12:30 PM EST Reads: 1,180
SYS-CON Events announced today that Linux Academy, the foremost online Linux and cloud training platform and community, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Linux Academy was founded on the belief that providing high-quality, in-depth training should be available at an affordable price. Industry leaders in quality training, provided services, and student certification passes, its goal is to c...
Jan. 19, 2017 12:15 PM EST Reads: 1,992
The unique combination of Amazon Web Services and Cloud Raxak, a Gartner Cool Vendor in IT Automation, provides a seamless and cost-effective way of securely moving on-premise IT workloads to Amazon Web Services. Any enterprise can now leverage the cloud, manage risk, and maintain continuous security compliance. Forrester's analysis shows that enterprises need automated security to lower security risk and decrease IT operational costs. Through the seamless integration into Amazon Web Services, ...
Jan. 19, 2017 12:00 PM EST Reads: 1,884
A lot of time, resources and energy has been invested over the past few years on de-siloing development and operations. And with good reason. DevOps is enabling organizations to more aggressively increase their digital agility, while at the same time reducing digital costs and risks. But as 2017 approaches, the hottest trends in DevOps aren’t specifically about dev or ops. They’re about testing, security, and metrics.
Jan. 19, 2017 11:45 AM EST Reads: 1,303
"We provide DevOps solutions. We also partner with some key players in the DevOps space and we use the technology that we partner with to engineer custom solutions for different organizations," stated Himanshu Chhetri, CTO of Addteq, in this SYS-CON.tv interview at DevOps at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Jan. 19, 2017 11:30 AM EST Reads: 4,334
2016 has been an amazing year for Docker and the container industry. We had 3 major releases of Docker engine this year , and tremendous increase in usage. The community has been following along and contributing amazing Docker resources to help you learn and get hands-on experience. Here’s some of the top read and viewed content for the year. Of course releases are always really popular, particularly when they fit requests we had from the community.
Jan. 19, 2017 10:15 AM EST Reads: 902
Hardware virtualization and cloud computing allowed us to increase resource utilization and increase our flexibility to respond to business demand. Docker Containers are the next quantum leap - Are they?! Databases always represented an additional set of challenges unique to running workloads requiring a maximum of I/O, network, CPU resources combined with data locality.
Jan. 19, 2017 10:15 AM EST Reads: 581
"We got started as search consultants. On the services side of the business we have help organizations save time and save money when they hit issues that everyone more or less hits when their data grows," noted Otis Gospodnetić, Founder of Sematext, in this SYS-CON.tv interview at @DevOpsSummit, held June 9-11, 2015, at the Javits Center in New York City.
Jan. 19, 2017 10:15 AM EST Reads: 4,881
An overall theme of Cloud computing and the specific practices within it is fundamentally one of automation. The core value of technology is to continually automate low level procedures to free up people to work on more value add activities, ultimately leading to the utopian goal of full Autonomic Computing. For example a great way to define your plan for DevOps tool chain adoption is through this lens. In this TechTarget article they outline a simple maturity model for planning this.
Jan. 19, 2017 10:15 AM EST Reads: 234
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions with...
Jan. 19, 2017 10:00 AM EST Reads: 5,566
Thanks to Docker, it becomes very easy to leverage containers to build, ship, and run any Linux application on any kind of infrastructure. Docker is particularly helpful for microservice architectures because their successful implementation relies on a fast, efficient deployment mechanism – which is precisely one of the features of Docker. Microservice architectures are therefore becoming more popular, and are increasingly seen as an interesting option even for smaller projects, instead of being...
Jan. 19, 2017 09:30 AM EST Reads: 2,184
You often hear the two titles of "DevOps" and "Immutable Infrastructure" used independently. In his session at DevOps Summit, John Willis, Technical Evangelist for Docker, covered the union between the two topics and why this is important. He provided an overview of Immutable Infrastructure then showed how an Immutable Continuous Delivery pipeline can be applied as a best practice for "DevOps." He ended the session with some interesting case study examples.
Jan. 19, 2017 09:15 AM EST Reads: 3,207
DevOps tends to focus on the relationship between Dev and Ops, putting an emphasis on the ops and application infrastructure. But that’s changing with microservices architectures. In her session at DevOps Summit, Lori MacVittie, Evangelist for F5 Networks, will focus on how microservices are changing the underlying architectures needed to scale, secure and deliver applications based on highly distributed (micro) services and why that means an expansion into “the network” for DevOps.
Jan. 19, 2017 08:30 AM EST Reads: 5,194
SYS-CON Events announced today that Catchpoint Systems, Inc., a provider of innovative web and infrastructure monitoring solutions, has been named “Silver Sponsor” of SYS-CON's DevOps Summit at 18th Cloud Expo New York, which will take place June 7-9, 2016, at the Javits Center in New York City, NY. Catchpoint is a leading Digital Performance Analytics company that provides unparalleled insight into customer-critical services to help consistently deliver an amazing customer experience. Designed ...
Jan. 19, 2017 07:45 AM EST Reads: 6,337
Internet of @ThingsExpo, taking place June 6-8, 2017 at the Javits Center in New York City, New York, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. @ThingsExpo New York Call for Papers is now open.
Jan. 19, 2017 07:30 AM EST Reads: 3,651
Docker containers have brought great opportunities to shorten the deployment process through continuous integration and the delivery of applications and microservices. This applies equally to enterprise data centers as well as the cloud. In his session at 20th Cloud Expo, Jari Kolehmainen, founder and CTO of Kontena, will discuss solutions and benefits of a deeply integrated deployment pipeline using technologies such as container management platforms, Docker containers, and the drone.io Cl tool...
Jan. 19, 2017 07:30 AM EST Reads: 964