|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.
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
Dec. 6, 2016 12:00 AM EST Reads: 837
Get deep visibility into the performance of your databases and expert advice for performance optimization and tuning. You can't get application performance without database performance. Give everyone on the team a comprehensive view of how every aspect of the system affects performance across SQL database operations, host server and OS, virtualization resources and storage I/O. Quickly find bottlenecks and troubleshoot complex problems.
Dec. 5, 2016 10:45 PM EST Reads: 2,068
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
Dec. 5, 2016 07:45 PM EST Reads: 2,223
@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.
Dec. 5, 2016 07:00 PM EST Reads: 1,850
In his session at 19th Cloud Expo, Claude Remillard, Principal Program Manager in Developer Division at Microsoft, contrasted how his team used config as code and immutable patterns for continuous delivery of microservices and apps to the cloud. He showed how the immutable patterns helps developers do away with most of the complexity of config as code-enabling scenarios such as rollback, zero downtime upgrades with far greater simplicity. He also demoed building immutable pipelines in the cloud ...
Dec. 5, 2016 07:00 PM EST Reads: 1,814
In IT, we sometimes coin terms for things before we know exactly what they are and how they’ll be used. The resulting terms may capture a common set of aspirations and goals – as “cloud” did broadly for on-demand, self-service, and flexible computing. But such a term can also lump together diverse and even competing practices, technologies, and priorities to the point where important distinctions are glossed over and lost.
Dec. 5, 2016 06:15 PM EST Reads: 1,557
Without lifecycle traceability and visibility across the tool chain, stakeholders from Planning-to-Ops have limited insight and answers to who, what, when, why and how across the DevOps lifecycle. This impacts the ability to deliver high quality software at the needed velocity to drive positive business outcomes. In his session at @DevOpsSummit 19th Cloud Expo, Eric Robertson, General Manager at CollabNet, showed how customers are able to achieve a level of transparency that enables everyone fro...
Dec. 5, 2016 05:30 PM EST Reads: 1,929
Monitoring of Docker environments is challenging. Why? Because each container typically runs a single process, has its own environment, utilizes virtual networks, or has various methods of managing storage. Traditional monitoring solutions take metrics from each server and applications they run. These servers and applications running on them are typically very static, with very long uptimes. Docker deployments are different: a set of containers may run many applications, all sharing the resource...
Dec. 5, 2016 04:45 PM EST Reads: 5,555
Join Impiger for their featured webinar: ‘Cloud Computing: A Roadmap to Modern Software Delivery’ on November 10, 2016, at 12:00 pm CST. Very few companies have not experienced some impact to their IT delivery due to the evolution of cloud computing. This webinar is not about deciding whether you should entertain moving some or all of your IT to the cloud, but rather, a detailed look under the hood to help IT professionals understand how cloud adoption has evolved and what trends will impact th...
Dec. 5, 2016 04:00 PM EST Reads: 2,559
Information technology is an industry that has always experienced change, and the dramatic change sweeping across the industry today could not be truthfully described as the first time we've seen such widespread change impacting customer investments. However, the rate of the change, and the potential outcomes from today's digital transformation has the distinct potential to separate the industry into two camps: Organizations that see the change coming, embrace it, and successful leverage it; and...
Dec. 5, 2016 02:45 PM EST Reads: 3,291
You have great SaaS business app ideas. You want to turn your idea quickly into a functional and engaging proof of concept. You need to be able to modify it to meet customers' needs, and you need to deliver a complete and secure SaaS application. How could you achieve all the above and yet avoid unforeseen IT requirements that add unnecessary cost and complexity? You also want your app to be responsive in any device at any time. In his session at 19th Cloud Expo, Mark Allen, General Manager of...
Dec. 5, 2016 01:45 PM EST Reads: 1,712
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 ...
Dec. 5, 2016 01:15 PM EST Reads: 2,171
"Dice has been around for the last 20 years. We have been helping tech professionals find new jobs and career opportunities," explained Manish Dixit, VP of Product and Engineering at Dice, in this SYS-CON.tv interview at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Dec. 5, 2016 11:15 AM EST Reads: 969
Rapid innovation, changing business landscapes, and new IT demands force businesses to make changes quickly. In the eyes of many, containers are at the brink of becoming a pervasive technology in enterprise IT to accelerate application delivery. In this presentation, attendees learned about the: The transformation of IT to a DevOps, microservices, and container-based architecture What are containers and how DevOps practices can operate in a container-based environment A demonstration of how ...
Dec. 5, 2016 10:15 AM EST Reads: 991
Application transformation and DevOps practices are two sides of the same coin. Enterprises that want to capture value faster, need to deliver value faster – time value of money principle. To do that enterprises need to build cloud-native apps as microservices by empowering teams to build, ship, and run in production. In his session at @DevOpsSummit at 19th Cloud Expo, Neil Gehani, senior product manager at HPE, discussed what every business should plan for how to structure their teams to delive...
Dec. 5, 2016 09:15 AM EST Reads: 1,432
Without lifecycle traceability and visibility across the tool chain, stakeholders from Planning-to-Ops have limited insight and answers to who, what, when, why and how across the DevOps lifecycle. This impacts the ability to deliver high quality software at the needed velocity to drive positive business outcomes. In his general session at @DevOpsSummit at 19th Cloud Expo, Phil Hombledal, Solution Architect at CollabNet, discussed how customers are able to achieve a level of transparency that e...
Dec. 5, 2016 06:45 AM EST Reads: 1,026
IT leaders face a monumental challenge. They must figure out how to sort through the cacophony of new technologies, buzzwords, and industry hype to find the right digital path forward for their organizations. And they simply cannot afford to fail. Those organizations that are fastest to the right digital path will be the ones that win. The path forward, however, is strewn with the legacy of decisions made long ago — often before any of the current leadership team assumed their roles. While it’s ...
Dec. 5, 2016 05:00 AM EST Reads: 1,649
Kubernetes is a new and revolutionary open-sourced system for managing containers across multiple hosts in a cluster. Ansible is a simple IT automation tool for just about any requirement for reproducible environments. In his session at @DevOpsSummit at 18th Cloud Expo, Patrick Galbraith, a principal engineer at HPE, discussed how to build a fully functional Kubernetes cluster on a number of virtual machines or bare-metal hosts. Also included will be a brief demonstration of running a Galera MyS...
Dec. 5, 2016 04:30 AM EST Reads: 5,266
As we enter the final week before the 19th International Cloud Expo | @ThingsExpo in Santa Clara, CA, it's time for me to reflect on six big topics that will be important during the show. Hybrid Cloud: This general-purpose term seems to provide a comfort zone for many enterprise IT managers. It sounds reassuring to be able to work with one of the major public-cloud providers like AWS or Microsoft Azure while still maintaining an on-site presence.
Dec. 5, 2016 04:00 AM EST Reads: 2,835
Between 2005 and 2020, data volumes will grow by a factor of 300 – enough data to stack CDs from the earth to the moon 162 times. This has come to be known as the ‘big data’ phenomenon. Unfortunately, traditional approaches to handling, storing and analyzing data aren’t adequate at this scale: they’re too costly, slow and physically cumbersome to keep up. Fortunately, in response a new breed of technology has emerged that is cheaper, faster and more scalable. Yet, in meeting these new needs they...
Dec. 5, 2016 12:45 AM EST Reads: 1,836