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Attack Vectors: Domain Name System Security Facilitation Initiative Technical Study Group Update

Over the past few months, the Domain Name System Security Facilitation Initiative Technical Study Group (DSFI-TSG) has progressed its work by discussing various past breaches and attack campaigns that either utilized or directly impacted the Domain Name System (DNS). The primary focus of this inquiry has been to enumerate all of the attack vectors utilized to gain insights into potential commonalities. Some of the issues we are considering are whether any attack vectors are utilized more frequently than others and which attack vectors have the most impact on DNS ecosystem security.

While this list is not inclusive to all of the attack vectors under discussion, it includes:

  • Registrant credential compromise
  • Registrar/reseller credential compromise
  • Registry credential compromise
  • Inadequate access control
  • Insecure third-party networks
  • Impersonating an authoritative name server
  • Impersonating a recursive resolver
  • Use of DNS as a covert channel
  • Use of DNS as data exfiltration
  • Denial of service
  • DNS cache poisoning 

Many malicious campaigns utilize a multitude of attack vectors. As the DSFI-TSG continues to work through each attack vector, the group is also delving into issues around potential mitigation techniques. Specifically, we are exploring what mitigation techniques exist for each attack vector; whether there are technical, operational, or process gaps in mitigation deployments; and where mitigation techniques do not exist.

As this part of the work continues, the aim is to start developing answers to questions 1, 2, and 4 of the DSFI-TSG charter’s Key Questions:

1. What are the mechanisms or functions currently available that address DNS security?

2. Can we identify the most critical gaps in the current DNS security landscape?

     a) What are the technical requirements needed to address the gaps?

     b) What operational best practices need to be developed, modified, promoted, or implemented to address the gaps?

     c) What are hindrances to deployments of best practices and other technical measures?

4. What are the risks associated with these gaps that may not be well understood?

    a) What are the risk considerations?

    b) Where are there gaps in knowledge of the threat models to the DNS ecosystem?

    c) What externalities do people need to be aware of?

The DSFI-TSG members and the ICANN org support staff recognize the ongoing challenge of conducting the work without face-to-face meetings. The group conducts its work through one-hour meetings every two weeks, augmented by three-hour online workshops once a month. You can follow our work on our webpage. I want to thank all of the DSFI-TSG contributors and the ICANN org support staff for their continued dedication to this work. 


    Domain Name System
    Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."