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SWITCH-CERT IT-Security Blog


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SWITCH Public DNS Resolver

SWITCH operates recursive name servers for its constituency, the Swiss research and education network. Over the last year we have continually added support for transport encryption protocols on our recursive name servers such as DNS over TLS (DoT) and more recently DNS over HTTPS (DoH).

In contrast to default unencrypted DNS which runs over UDP/TCP Port 53 , both of these standards (DoT, DoH) use encrypted protocols which provide privacy for DNS queries between the client (application) and the recursive name server. This eliminates opportunities for eavesdropping and on-path tampering with DNS queries on the network.

Our motivation for enabling encrypted DNS protocols on our recursive name servers have been that some client applications (mostly Android 9) probe for DoT support and use it if available by default. Over the last year, other widely used applications have added support for encrypted DNS protocols. Most notably the web browser Mozilla Firefox which supports DoH but has not turned it on by default.

Opportunistic encryption of DNS queries and responses as it is used by Android 9 by default is one use case of DoT. However, some users want to pin a specific recursive name server regardless in which network they are or also to authenticate the name server. To support this use case, we have opened our recursive name servers over encrypted transport protocols to the Internet. You will find more information about the SWITCH Public DNS service and how to use it on this website:

https://www.switch.ch/security/info/public-dns/

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Attacks on DNS continue, targets are also in Switzerland

Attacks on the domain name system continue

Talos, the intelligence group of CISCO reported in their blog that their monitoring shows that attacks on the domain name system (DNS) by “Sea Turtle” continue.  The attack technique used is similar than before, the actors compromise name server records to take ownership of the domain. They then provide false information to selected parties (e.g certificate authorities, mail users) which leads to the disclosure of email credentials of the targeted organisations. These credentials give initial access to the victims E-mails accounts and other resources and are a starting point for further attacks.

Victims in Switzerland

For the first time, Talos also reported victims in Switzerland.

Geographic Location of Sea Turtle Victims by Talos

While Talos didn’t disclose the targeted organizations they identified these groups as primary targets:

  • Government organizations
  • Energy companies
  • Think tanks
  • International non-governmental organizations
  • At least one airport

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DNSSEC Usage in Switzerland is on the rise after widespread attacks on the Domain Name System

Attacks on the DNS System

Cyber attacks on the DNS system are not new. Cache poisoning, Domain Hijacking and BGP injections of routes to public DNS resolvers happen regularly, but they usually don’t get much attention as they target the Internet’s core infrastructure and are not directly visible to end users in most cases. This time it was different. The recent widespread DNS hijacking attacks on several Mid East, North African and European and North American governments and infrastructure providers, published by Ciscos Talos showed that DNS attacks are a real threat to cyber security. Netnod, one of the affected infrastructure providers issued a statement, that called, amongst other domain security mechanisms, for the implementation of the DNS Security Extensions (DNSSEC).

The analysis of these attacks also convinced the Internet Corporation for Assigned Names and Numbers (ICANN) that there is an ongoing and significant risk to key parts of the System (DNS) infrastructure. ICANN issued a call for “Full DNSSEC Deployment to Protect the Internet” across all unsecured domain names.

The question is if  these attacks and the awareness that DNSSEC is an absolute essential base layer protection for domain names had some effects on the Implementation of DNSSEC Switzerland?

More DNSSEC signed domain names

As a ccTLD operator SWITCH publishes the number of DNSSEC signed .ch and .li domain names every month. While the number of signed domain names is still very low at around 3-4% we see a rise in the numbers of signed domain names for two years now.

DNSSEC signed .ch domain names 1.4.2019

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Top 1000 .ch Domain Names

UPDATE 19.02.2019:

From February 2019 on there will be a few small changes. A co-worker, Antoine, has discovered a flaw in the current measurement of the top 1000 .ch domain names which has been removed by now. Since we only counted the number of distinct IP addresses per domain for both IP versions, using IPv6 one can easily send queries from a whole /64 range which results in approximately 1.8*10^19 different addresses. Being a private customer of the Swiss ISP Init7 even gives you an entire /48 range. Like that you can easily push a domain name to the top! In order to prevent this from happening we will now count the distinct number of ASes per domain.

Additionally, we will provide 2 lists from now on. One that contains a ranking based on ALL queries, i.e. including queries that have returned NXDOMAIN, and one whithout those NXDOMAIN queries. Previously, we just provided the former. Continue reading


Additional DNSSEC Training with PowerDNS on May 7 and 8

We announced 3 one day DNS trainings in the end of February and all three trainings where fully booked within 24 hours. We are happy to see so much demand for DNSSEC in Switzerland.
We managed to add two more dates for the DNSSEC training together with PowerDNS
The training will be given at the following dates in Zurich:

7.5. Zurich, SWITCH
8.5. Zurich, SWITCH

The one day training will give you an introduction into DNSSEC and show you how to sign DNS zones on an autoritative DNS server.
We will use PowerDNS for the practical and hands on part. PowerDNS contains support for DNSSEC, enabling the easy serving of DNSSEC secured data, with minimal administrative overhead.

Agenda:

• Short introduction to DNSSEC
• how DNSSEC works
• keys / signatures / NSEC / NSEC3
• Working with DNSSEC and the PowerDNS Authoritative server
• Short overview over PowerDNS Authoritative server backends (MySQL, PostgreSQL, BIND, pipe, …)
• DNSSEC signing
• Pre-signed zones
• CDS
• Zone transfers
• Utilities (pdnsutil)
• The PowerDNS ALIAS record (and its future)

Required skills: Unix system administrator skills and DNS server know how.The training will be delivered in english.

More information and registration here:

https://www.eventbrite.com/e/dnssec-training-zurich-may-7-tickets-44474772241
https://www.eventbrite.com/e/dnssec-training-zurich-may-8-tickets-44474795310


A Day in the Life of nic.ch

Ever wondered what the DNS traffic looks like on a usual day on a .ch name server? This article briefly sketches the landscape of systems querying .ch domains. To be exact, the following statistics and statements are based on a small subset of the overall data since the underlying sources just consist of 2 out of 8 name servers, i.e. a.nic.ch and b.nic.ch.  Overall the .ch zone consists of 8 name servers distributed all over the world. While some of them are setup as anycast network, others are set up traditionally as unicast servers located in a single data center.

We capture the DNS traffic as pcaps and subsequently process and store it with the help of Entrada which relies on HDFS and Impala. Currently, we operate a Hadoop cluster with 7 data nodes which provides us with a good basis for future in-depth analysis.

The following sections discuss two statistics that we publish on www.nic.ch in greater detail.

Who queries the name servers?

To start with, let’s have a look at who queries our name servers. Figure 1 shows the top 10 countries in terms of generated DNS traffic observed during week 4 of 2018. Additionally, the share of distinct IP addresses per country is displayed with a second bar. Since the original DNS traffic does not contain explicit information about the country where the query originates from this information is being added by Entrada with the help of the Maxmind database. To have a more representative image of the DNS landscape, Google resolvers and OpenDNS resolvers are excluded from this statistic.  Although from the queries themselves one cannot be sure about the nature of the querying system, for convenience, throughout this article we’ll call those systems resolvers.

top_ten_countries.png

Figure 1

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DNSSEC training with PowerDNS in Switzerland

SWITCH is organising a one day DNSSEC training together with PowerDNS

The training will be given at the following dates:

9.4. Zurich, SWITCH
10.4. Bern, Uni
11.4. Carouge HESGE

The one day training will give you an introduction into DNSSEC and show you how to sign DNS zones on an autoritative DNS server.
We will use PowerDNS for the practical and hands on part. PowerDNS contains support for DNSSEC, enabling the easy serving of DNSSEC secured data, with minimal administrative overhead.

Agenda:

• Short introduction to DNSSEC
• how DNSSEC works
• keys / signatures / NSEC / NSEC3
• Working with DNSSEC and the PowerDNS Authoritative server
• Short overview over PowerDNS Authoritative server backends (MySQL, PostgreSQL, BIND, pipe, …)
• DNSSEC signing
• Pre-signed zones
• Zone transfers
• Utilities (pdnsutil)
• The PowerDNS ALIAS record (and its future)

Required skills: Unix system administrator skills and DNS server know how.The training will be delivered in english.

More information and registration here:

Zurich: https://www.eventbrite.com/e/dnssec-training-zurich-tickets-43350331007
Bern: https://www.eventbrite.com/e/dnssec-training-bern-tickets-43592055010
Carouge: https://www.eventbrite.com/e/dnssec-training-carouge-tickets-43592840359

Update 28.2.2018: All three trainings are fully booked after only 24 hours. We are happy to see so much interest in DNSSEC in Switzerland. Waitlist is now open.