Coordinating Attack Response at Internet Scale (CARIS) Workshop Report
RFC 8073

Internet Architecture Board (IAB)                            K. Moriarty
Request for Comments: 8073                                       M. Ford
Category: Informational                                       March 2017
ISSN: 2070-1721

 Coordinating Attack Response at Internet Scale (CARIS) Workshop Report

Abstract

   This report documents the discussions and conclusions from the
   Coordinating Attack Response at Internet Scale (CARIS) workshop that
   took place in Berlin, Germany on 18 June 2015.  The purpose of this
   workshop was to improve mutual awareness, understanding, and
   coordination among the diverse participating organizations and their
   representatives.

   Note that this document is a report on the proceedings of the
   workshop.  The views and positions documented in this report are
   those of the workshop participants and do not necessarily reflect IAB
   views and positions.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Architecture Board (IAB)
   and represents information that the IAB has deemed valuable to
   provide for permanent record.  It represents the consensus of the
   Internet Architecture Board (IAB).  Documents approved for
   publication by the IAB are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc8073.

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Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Sessions and Panel Groups . . . . . . . . . . . . . . . . . .   4
     2.1.  Coordination between CSIRTs and Attack Response
           Mitigation Efforts  . . . . . . . . . . . . . . . . . . .   5
     2.2.  Scaling Response to DDoS and Botnets Effectively and
           Safely  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     2.3.  DNS and RIRs: Attack Response and Mitigation  . . . . . .   9
     2.4.  Trust Privacy and Data Markings Panel . . . . . . . . . .  10
   3.  Workshop Themes . . . . . . . . . . . . . . . . . . . . . . .  11
   4.  Next Steps  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     4.1.  RIR and DNS Provider Resources  . . . . . . . . . . . . .  12
     4.2.  Education and Guidance  . . . . . . . . . . . . . . . . .  12
     4.3.  Transport Options . . . . . . . . . . . . . . . . . . . .  12
     4.4.  Updated Template for Information Exchange Groups  . . . .  13
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   6.  Informative References  . . . . . . . . . . . . . . . . . . .  13
   Appendix A. Workshop Attendees  . . . . . . . . . . . . . . . . .  15
   IAB Members at the Time of Approval . . . . . . . . . . . . . . .  15
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  16
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16

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1.  Introduction

   The Internet Architecture Board (IAB) holds occasional workshops
   designed to consider long-term issues and strategies for the
   Internet, and to suggest future directions for the Internet
   architecture.  This long-term planning function of the IAB is
   complementary to the ongoing engineering efforts performed by working
   groups of the Internet Engineering Task Force (IETF), under the
   leadership of the Internet Engineering Steering Group (IESG) and area
   directorates.

   The Internet Architecture Board (IAB) and the Internet Society (ISOC)
   hosted a day-long Coordinating Attack Response at Internet Scale
   (CARIS) workshop on 18 June 2015 in coordination with the Forum for
   Incident Response and Security Teams (FIRST) Conference in Berlin.
   The workshop included members of the FIRST community, attack response
   working group representatives, network and security operators,
   Regional Internet Registry (RIR) representatives, researchers,
   vendors, and representatives from standardization communities.  The
   key goals of the workshop were to improve mutual awareness,
   understanding, and coordination among the diverse participating
   organizations.  The workshop also aimed to provide the attendees with
   greater awareness of existing efforts to mitigate specific types of
   attacks, and greater understanding of the options available to
   collaborate and engage with these efforts.

   The day-long workshop included a mix of invited talks and panel
   discussion sessions with opportunities to collaborate throughout,
   taking full advantage of the tremendous value of having these diverse
   communities with common goals in one room.  There were approximately
   50 participants engaged in the CARIS workshop.

   Attendance at the workshop was by invitation only.  Prior to the
   workshop, existing attack-mitigation working groups were asked to
   complete a survey.  The data gathered through this questionnaire,
   including how third parties can participate in or contribute to the
   attack-mitigation working group, was shared with all of the
   participants at the workshop to better enable collaboration [ISOC].
   Attendees were also selected from submissions of two-page position
   papers that included some key insight or challenge relevant to the
   broader group.  Paper topics included research topics related to
   attack mitigation or information sharing/exchange, success stories,
   lessons learned, and more in-depth studies on specific topics such as
   privacy or trust.

   The program committee received 25 papers and 19 template submissions.
   The template submissions will be maintained by the Internet Society,
   and as a result of the workshop, they will be amended to provide

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   additional value to the Computer Security Incident Response Teams
   (CSIRTs) and attack response communities/operators on their
   information exchange capabilities.  The CARIS participants found the
   template submissions to be very useful in coordinating their future
   attack mitigation efforts.  This initiative is a new, open for the
   global community, and hosted in a neutral location.  All submissions
   are available online and are linked from the agenda [AGENDA].

   The workshop talks and panels involved full participation from
   attendees who were required to read all the submitted materials.  The
   panels were organized to spur conversation between specific groups to
   see if progress could be made towards more efficient and effective
   attack mitigation efforts.  See [KME] for additional information on
   possible approaches to accomplish more effective attack response and
   information exchanges with methods that require fewer analysts.

   The workshop was run under the Chatham House Rule to facilitate the
   exchange of sensitive information involved with incident response.
   As such, there was no recording, but minutes were taken and used to
   aid in the generation of this report.  Comments will not be
   attributed to any particular attendee, nor will organizations be
   named in association with any discussion topics that were not made
   public through submission templates or papers by the submitter and
   organization.

2.  Sessions and Panel Groups

   After an initial presentation to set the stage and elaborate the
   goals of the workshop, the day was divided into five sessions as
   follows:

   1.  Coordination between CSIRTs and attack-response mitigation
       efforts

   2.  Scaling response to Distributed Denial-of-Service (DDoS) and
       botnets effectively and safely

   3.  Infrastructure: DNS and RIR providers and researchers

   4.  Trust and Privacy with the exchange of potentially sensitive
       information

   5.  Implications for Internet architecture and next steps

   The remainder of this report will provide more detail on each of
   these sessions.

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2.1.  Coordination between CSIRTs and Attack Response Mitigation Efforts

   The first panel session on Coordination between CSIRTs and attack
   mitigation efforts included representatives from several
   organizations that submitted templates describing their
   organization's attack mitigation efforts.  This panel was
   purposefully a cross section of organizations attending to see if
   there were new opportunities to collaborate and improve efficiency,
   thereby better scaling attack mitigation.  The panelists described
   their efforts with the following questions in mind:

   o  What is the use case for their organization?

   o  Where are they focusing their efforts?

   o  How can others engage with their organization?

   o  Who participates in their organization today?

   For each of the following organizations, additional information can
   be found in their template submissions [ISOC].

   The following summaries are to be read in the context of the workshop
   and not as standalone descriptions for each organization.  These
   summaries are a result of the workshop discussions.

   o  ENISA is the European Network and Information Security Agency
      [ENISA].  While ENISA provides support for the community in the
      form of education, training, and collaboration on security and
      attack mitigation, it does not offer a service for attack response
      or mitigation.

   o  The Anti-Phishing Working Group (APWG) offered examples of
      operator-driven exchanges focused on specific use cases that
      involve hundreds of participating organizations daily.  The APWG
      operates a data clearinghouse and provides infrastructure to
      support meaningful data exchanges and maintains a current set of
      data through these interactions.  More can be learned on the APWG
      website [APWG] in addition to their template submission.

   o  The Research and Education Networking Information Sharing and
      Analysis Center (Ren-ISAC) employs an interesting operational
      model that scales well through automation, exchanging actionable
      information between 500 universities and automatically
      implementing controls.  Since many universities cannot respond to
      incidents in real time due to a scarcity of resources, REN-ISAC
      leverages a small number of analysts to accomplish the task of
      protecting many universities through automation.  The key to the

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      success of their project is providing tools that allow
      organizations to make use of incident data operationally.  They
      are currently working to develop open-source tools to track
      metrics more formally [REN-ISAC].

   o  CERT.br is the Brazilian Computer Emergency Response Team (CERT)
      that has made impressive progress in a short amount of time.
      CERT.br is the national focal point for incident reporting,
      collection, and dissemination of threat and attack trend
      information in Brazil.  CERT.br works to increase awareness and
      incident-handling capabilities in the country as well as assisting
      to establish new CSIRTs.  In addition to providing training and
      awareness campaigns, they distribute network security honeypots
      and have a primary focus on network monitoring.  CERT.br requires
      active participation from third parties wishing to collaborate and
      exchange data with them [CERT.BR].

   o  MyCERT's mission is to address the security concerns of Malaysian
      Internet users and reduce the probability of successful attacks
      [MYCERT].  They have been operational since 1997.  MyCERT is
      responsible for incident handling of unauthorized intrusions,
      identity theft, DDoS attacks, etc.  MyCERT handles computer
      security incidents in Malaysia, provides malware research, and
      technical coordination.  In addition to incident response and
      coordination activities, MyCERT members provide talks and
      training, as well as local and regional security exercises.
      MyCERT also provides incident alerts and advisories on
      vulnerabilities, breaches, etc.

   o  The CERT Coordination Center (CERT/CC) has been operational since
      1998 on an international and national scale [CERTCC].  They have
      long been known for their software vulnerability work and the
      national vulnerability database in the US (Common Vulnerabilities
      and Exposures -- CVEs) and informing organizations of
      vulnerabilities.  CERT/CC helps to coordinate between vendors and
      researchers for improved collaborations.  CERT/CC provides
      guidance on dealing with the aftermath of incidents, risk
      assessment best practice, bug bounties, and other incident-related
      areas.

   Highlights from the panel discussion:

   o  Passive surveillance by state actors has impacted incident
      response activities due to the erosion of trust between
      communities.

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   o  Government involvement in information exchange efforts has not
      been productive.  Despite lots of discussion, there have not been
      useful outcomes.

   o  There is more interest in consuming feeds of information than
      sharing information.

   o  Ego has been a big issue for improving data sharing, as have
      reputation-related concerns when sharing or receiving data.

   o  There is a perception of weakness around organizations that share
      attack information in some regions.

   o  Sharing in isolation doesn't help, it must lead to operational
      return on investment.

   o  Language barriers have been an issue for some national CSIRTs.

   o  Sharing too much information leads to capacity and resource issues
      for receiving organizations.  Organizations directly receiving
      feeds can often misinterpret data and think they are under attack
      when it is not the case.  Operational models are preferred where
      data exchanges have a direct impact on improving the efficiency of
      a small number of analysts to impact many.

   o  Privacy regulations restricting some organizations from sharing IP
      address information have had an impact on the effectiveness of
      incident data exchanges.  ENISA is currently running a study on
      this impact (this point was raised by several attendees).

   o  Too many efforts are using data just for blocking attacks and not
      for operational mitigation and elimination of vulnerabilities as
      part of their incident response effort.  Note: Operational efforts
      stand out in that they do eliminate threats and update data
      warehouses.

   o  Involvement of vendors is needed to better scale attack response.
      This is not seen as a need by all groups, but some sharing groups
      with an operational focus are looking for improved efficiencies to
      leverage a small number of analysts more productively.  Analysts
      are a limited resource in this technical area of expertise.

   o  Enterprises don't want more security boxes in their networks as
      they don't have the resources to manage them, so involving vendors
      doesn't mean deploying more equipment, but improving automated
      controls and the elimination of threats wherever possible.  False
      positives are still an issue, which can be problematic for some
      automation activities.

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2.2.  Scaling Response to DDoS and Botnets Effectively and Safely

   The first invited talk at the workshop provided an interesting
   history of Distributed Denial-of-Service (DDoS) attacks and the
   evolution of botnets as well as the methods to combat these threats.
   The paper by Dave Dittrich [DD1] is available to learn more of this
   history.  This section of the report will focus on the workshop
   discussion in an effort to benefit from the workshop attendees'
   thoughts concerning how to better scale our response to these
   threats.

   Key points from the discussion:

   o  Of the attack types discussed, DDoS and botnets appear to be the
      furthest along in terms of efficient and effective response.
      Other efforts can learn from this experience.  There has not been
      any interaction between these two attack types that may benefit
      from information exchange tied to remediation activities since
      botnets can be the source of DDoS attacks.

   o  There is a disparity between short-term mitigation goals and
      actual eradication of DDoS and botnet threats.  The question was
      raised: how do we normalize the same data in different ways to
      serve different goals?  In other words, DDoS traffic is often the
      result of botnets, but the data is not shared between the service
      providers and vendors responding to DDoS threats and those
      actively mitigating and eradicating botnets.

   o  There are ad hoc trust groups within the operations security
      (OPSEC) community today.  The Cybercrime Response Advisory Group
      (CRAG) is one example.

   o  Filtering and triage is an issue, but this is a solvable problem.

   o  The IETF DDOS Open Threat Signaling (DOTS) working group was
      discussed and compared to a previous effort, Real-time Inter-
      network defense (RID) [RFC6545].  It was stated that the two are
      similar, except DOTS makes use of current data formats and
      protocols and has the support of multiple DDoS vendors.  One of
      the goals of DOTS is to have this solution be the "glue" between
      vendors to communicate shared data using standard formats and
      protocols developed in open-source tools.

   o  The IETF Interface to Network Security Functions (I2NSF) effort
      was discussed to explore ways of leveraging infrastructure to
      combat DDoS attacks.

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   o  Vendors discussed existing capabilities for DDoS mitigation, while
      data-sharing groups discussed their mitigation activities related
      to botnets (see the submissions under the heading "Panel on
      Scaling Attack Response for DDoS and BotNets" in the workshop
      agenda [AGENDA]).

   o  Trust and reputation of data sources is still a concern.

   o  One of the exchange groups has a goal of "automated takedowns" for
      botnets.  However, they think they will always have a need for
      manual intervention.

   o  The need for multiple levels of trust seemed to be prevalent among
      those participating in the panel discussion.  Intelligence
      agencies erode trust (this was also mentioned in the first panel
      in terms of surveillance activities from governments).

   o  Although trust was discussed in this panel and there are concerns,
      it was noted that trust is not as big a barrier for DDoS and
      botnet mitigation, and this is likely due to the operational
      experience of the participants.

2.3.  DNS and RIRs: Attack Response and Mitigation

   This session was a shift from other sessions in the day as the
   panelists were infrastructure providers for those combating attacks.
   This session was of interest to see how attack and incident
   responders could better collaborate with DNS infrastructure
   organizations and RIRs.  These groups have not interacted in the
   past, and it was interesting to see the collaboration opportunities
   since the workshop participants rely on these services to do their
   jobs.  From the panelists' perspective, DNS and RIRs are separate
   worlds where they spend a lot of time trying to educate policy makers
   about how they work together to make the Internet work.

   Key discussion points:

   o  The use of passive DNS in attack mitigation was described.

   o  RIRs discussed the data they maintain and provide, including
      worldwide BGP update data and root DNS server data.  These
      datasets are available to share with researchers and could be of
      interest to those working on attack response.  The current way the
      data is made available does not scale, and ideas were discussed in
      the workshop to improve the scalability should this become a more
      widely used resource.

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   o  Some of the global RIRs already actively coordinate with incident
      responders in their region.  In some cases, they do facilitate
      information sharing as well as provide education and training.
      Data shared out by RIRs is anonymized.

   o  A concern was raised regarding overlapping efforts and a request
      was made for the IETF and ISOC to pay attention to this and help.
      This workshop was one step toward that in bringing together this
      diverse community.  The participants wished to see this type of
      event repeated for future cross area collaboration between the
      diverse set of groups that often only meet within their silo.

   o  Standards for APIs to access data consistently from RIRs and
      scoring methods were discussed as possible ways to scale trust.
      Questions were raised as to how this might be possible.  One might
      receive unverifiable data about a network.  They may be able to
      verify the source's identity, verify route origins, but won't be
      able to verify the provenance of data.

2.4.  Trust Privacy and Data Markings Panel

   Why don't organizations share data?  The answer seems to be a mix of
   privacy, legal, technical/mundane, cultural, and communication
   issues.  There are also concerns about sharing proprietary data with
   competitors.  Having said that, most of these reasons were dismissed
   as bogus by the more operationally focused participants in the
   workshop.  Lawyers need contextual education for the intersection of
   law and technology.  Sensitive data is still an issue as one can't
   control what others do with data once it is shared.

   Key points from the panel discussion:

   o  Operationally focused groups do retain/rate/re-mark confidence
      levels based upon the submitter's reputation.

   o  The Traffic Light Protocol (TLP) [TLP] was discussed.  While TLP
      is useful to some groups who exchange data, others find that it is
      not granular enough for their needs.

   o  In many cases, when data is shared, the user never knows, and
      there is no way to manage that disclosure.

   o  Trust is personal.  When sharing circles get too large, trust
      breaks down.  The personal relationship aspect of information
      sharing communities was emphasized by several who are actively
      exchanging data.  This was a very prevalent theme.

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   o  A point of comparison was made with consumer goods, and it was
      observed that trademarks are a byproduct of the Industrial
      Revolution.  The question was raised: does trust need branding?

   o  Observing participants noted that there appear to be cabals
      operating the groups based on the current trust notions.  This was
      not disputed.

   o  Transparency is vital to maintain trust.

   o  Participants working on automation have found a need to share with
      organizations of all sizes as well as a need to share both
      synchronously and asynchronously.  In an automated model, they
      must ensure data sources are "authorized" and these efforts have
      encountered questions about anonymization as well as regional
      regulatory perspectives as they vary.

   o  Another automation effort found that people have different upper
      limits for trust group scale, which is sometimes based on
      individualized knowledge of other participants and having a
      comfort level with them.  Social interaction (beer) is a common
      thread amongst sharing partners to build trust relationships.  The
      relationships are formed between individuals and not necessarily
      between organizations.

   o  It's rare for any single piece of information to be clearly
      identifiable as private or public.  The temptation is to say that
      information isn't Personally Identifiable Information (PII).  In
      aggregate, however, non-PII can become PII.

   o  There was common agreement that reputation is fundamental.

3.  Workshop Themes

   During the course of the day, a couple of themes recurred in the
   discussions.  Firstly, in order to better scale attack response
   through improvements to the efficiency and effectiveness of
   information exchanges:

   1.  Exchanging data should not be just for the purpose of creating
       blacklists that could be redundant efforts.

   2.  Involving service providers and vendors to better coordinate and
       scale response is key.

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   Secondly, information security practitioners are a scarce resource:

   1.  Training and education was discussed to improve this gap, both to
       train information security professionals and others in IT on
       basic network and system hygiene.

   2.  Leveraging resources to better scale response, using fewer
       resources is critical.

4.  Next Steps

4.1.  RIR and DNS Provider Resources

   Workshop participants expressed an interest in expanded information
   about the resources and assistance offered by the RIRs and DNS
   providers.  Participants are going to define what is needed.

4.2.  Education and Guidance

   Another recurring theme was the lack of knowledge in the community
   about basic security principles such as ingress and egress filtering
   explained in BCP 38 [RFC2827].  The CSIRTs, operators, and vendors of
   attack mitigation tools found this particularly frustrating.  As a
   result, follow up activities may include determining if security
   guidance BCPs require updates or to determine whether there are
   opportunities to educate people on these basic principles already
   documented by the IETF.

4.3.  Transport Options

   One of the more lively discussions was the need for better transports
   for information exchange.  Real-time Inter-network Defense (RID)
   [RFC6545] was published 5 years ago.  While the patterns established
   in RID still show promise, there are updated solutions being worked
   on.  One such solution is in the IETF DOTS working group that has an
   approach similar to RID with updated formats and protocols to meet
   the demands of today's DDoS attacks.  While Trusted Automated
   eXchange of Indicator Information (TAXII -- another transport option)
   is just in transition to Organization for the Advancement of
   Structured Information Standards (OASIS), its base is similar to RID
   in its use of SOAP-like messaging, which will likely prevent it from
   scaling to the demands of the Internet.  Vendors also cited several
   interoperability challenges of TAXII in workshop discussions.
   Alternatively, XMPP-Grid has been proposed in the IETF Security
   Automation and Continuous Monitoring (SACM) working group and it
   offers promise as the data exchange protocol for deployment at scale.
   Extensible Messaging and Presence Protocol (XMPP) [RFC6120]
   inherently meets the requirements for today's information exchanges

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   with features such as publish/subscribe, federation, and use of a
   control channel.  XMPP-Grid is gaining traction with at least 10
   vendors using it in their products and several more planning to add
   support [APPALA].  Review and discussion of this document would be
   helpful as it transitions to the Managed Incident Lightweight
   Exchange (MILE) working group as an outcome of the workshop.
   Representational State Transfer (REST) was also brought up as a
   needed interface because of the low barrier to use [REST].  The IETF
   MILE Working Group has discussed a document detailing a common
   RESTful interface (ROLIE) that could be used with any data format and
   this may also be of interest [ROLIE].

4.4.  Updated Template for Information Exchange Groups

   One of the submission options was for organizations actively
   exchanging data to submit a form describing their work to reduce
   computer security incidents.  The CSIRTs, in particular, liked having
   access to this information in a neutral location like the Internet
   Society.  However, they wanted to see amendments to the format to
   improve its usefulness.  There was a desire to have this used by
   additional information exchange groups, thereby creating a living
   library to improve awareness about how to become a member, benefit
   from, or contribute to the success of the attack response and CSIRT
   information exchange platforms.

5.  Security Considerations

   The CARIS workshop was focused on security and methods to improve the
   effectiveness and efficiency of attack response to enable better
   scaling.  This report provides a summary of the workshop discussions
   and identifies some outcomes to improve security.  As such, no
   additional considerations are provided in this section.

6.  Informative References

   [AGENDA]   "Agenda: Coordinating Attack Response at Internet Scale
              (CARIS) Workshop", 2015,
              <https://www.iab.org/activities/workshops/caris/agenda/>.

   [APPALA]   Cam-Winget, N., Ed., Appala, S., and S. Pope, "XMPP
              Protocol Extensions for Use with IODEF", Work in Progress,
              draft-ietf-mile-xmpp-grid-01, October 2016.

   [APWG]     "APWG Homepage", <http://www.antiphishing.org>.

   [CERT.BR]  "Brazilian National Computer Emergency Response Team
              Homepage", <http://www.cert.br/en/>.

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   [CERTCC]   "CERT Coordination Center Homepage",
              <https://www.cert.org>.

   [DD1]      Dittrich, D., "Taking Down Botnets - Background", April
              2015, <https://www.iab.org/wp-content/IAB-uploads/2015/
              04/CARIS_2015_submission_21.pdf>.

   [ENISA]    "European Union Agency for Network and Information
              Security Homepage", <https://www.enisa.europa.eu>.

   [ISOC]     "CARIS Workshop Template Submissions 2015",
              <https://www.internetsociety.org/doc/
              caris-workshop-template-submissions-2015>.

   [KME]      Moriarty, K., "Kathleen Moriarty Blog Series", July 2015,
              <http://blogs.rsa.com/author/kathleen-moriarty/>.

   [MYCERT]   "Malaysia Computer Emergency Response Team Homepage",
              <https://www.mycert.org.my/en/>.

   [REN-ISAC] "Research and Education Networking Information Sharing and
              Analysis Center Homepage", <http://ren-isac.net>.

   [REST]     Fielding, R., "Architectural Styles and the Design of
              Network-based Software Architectures", Ph.D. Dissertation,
              University of California, Irvine, 2000,
              <http://www.ics.uci.edu/~fielding/pubs/dissertation/
              fielding_dissertation.pdf>.

   [RFC2827]  Ferguson, P. and D. Senie, "Network Ingress Filtering:
              Defeating Denial of Service Attacks which employ IP Source
              Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
              May 2000, <http://www.rfc-editor.org/info/rfc2827>.

   [RFC6120]  Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Core", RFC 6120, DOI 10.17487/RFC6120,
              March 2011, <http://www.rfc-editor.org/info/rfc6120>.

   [RFC6545]  Moriarty, K., "Real-time Inter-network Defense (RID)",
              RFC 6545, DOI 10.17487/RFC6545, April 2012,
              <http://www.rfc-editor.org/info/rfc6545>.

   [ROLIE]    Field, J., Banghart, S., and D. Waltermire, "Resource-
              Oriented Lightweight Information Exchange", Work in
              Progress, draft-ietf-mile-rolie-06, March 2017.

   [TLP]      "Traffic Light Protocol (TLP) Matrix and Frequently Asked
              Questions", <https://www.us-cert.gov/tlp>.

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RFC 8073                          CARIS                       March 2017

Appendix A.  Workshop Attendees

   In alphabetical order by first name, workshop attendees were: Adli
   Wahid, Alexey Melnikov, Andrew Sullivan, Arnold Sykosch, Brian
   Trammell, Chris Morrow, Cristine Hoepers, Dario Forte, Dave Cridland,
   Dave Dittrich, Eliot Lear, Foy Shiver, Frank Xialiang, Graciella
   Martinez, Jessica Stienberger, Jim Duncan, Joe Hildebrand, John Bond,
   John Graham-Cummings, John Kristoff, Kathleen Moriarty, Klaus
   Steding-Jessen, Linda Dunbar, Marco Obiso, Martin Stiemerling, Mat
   Ford, Merike Kaeo, Michael Daly, Mio Suzuki, Mirjam Kuehne, Fu
   TianFu, Nancy Cam-Winget, Nik Teague, Pat Cain, Roland Dobbins, Roman
   Danyliw, Rosella Mattioli, Sandeep Bhatt, Scott Pinkerton, Sharifah
   Roziah Mohd Kassim, Stuart Murdoch, Takeshi Takahashi, Ted Hardie,
   Tobias Gondrom, Tom Millar, Tomas Sander, Ulrich Seldeslachts,
   Valerie Duncan, and Wes Young.

IAB Members at the Time of Approval

   The IAB members at the time this memo was approved were (in
   alphabetical order):

      Jari Arkko
      Ralph Droms
      Ted Hardie
      Joe Hildebrand
      Russ Housley
      Lee Howard
      Erik Nordmark
      Robert Sparks
      Andrew Sullivan
      Dave Thaler
      Martin Thomson
      Brian Trammell
      Suzanne Woolf

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Acknowledgements

   Thanks are due to the members of the program committee (in
   alphabetical order) for their efforts to make the CARIS workshop
   possible and a productive session with cross area expertise: Matthew
   Ford (Internet Society, UK), Ted Hardie (Google, USA), Joe Hildebrand
   (Cisco, USA), Eliot Lear (Cisco, Switzerland), Kathleen M.  Moriarty
   (EMC Corporation, USA), Andrew Sullivan (Dyn, USA), and Brian
   Trammell (ETH Zurich, Switzerland).

   Thanks are also due to the CARIS workshop sponsors:

   o  FIRST provided a room and excellent facilities in partnership with
      their annual conference in Berlin.

   o  The Internet Society hosted the social event, a boat ride through
      the canals of Berlin.

   o  EMC Corporation provided lunch, snacks, and coffee throughout the
      day to keep the attendees going.

Authors' Addresses

   Kathleen M. Moriarty
   176 South Street
   Hopkinton, MA
   United States of America

   Email: Kathleen.Moriarty@dell.com

   Mat Ford
   Galerie Jean-Malbuisson 15
   Geneva
   Switzerland

   Email: ford@isoc.org

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