Internet-Draft CARIS2 Report October 2020
Moriarty Expires 12 April 2021 [Page]
Internet Engineering Task Force
Intended Status:
K. Moriarty
Dell Technologies

Coordinating Attack Response at Internet Scale 2 (CARIS2) Workshop Report


The Coordinating Attack Response at Internet Scale (CARIS) 2 workshop, sponsored by the Internet Society, took place 28 February and 1 March 2019 in Cambridge, Massachusetts, USA. Participants spanned regional, national, international, and enterprise CSIRTs, operators, service providers, network and security operators, transport operators and researchers, incident response researchers, vendors, and participants from standards communities. This workshop continued the work started at the first CARIS workshop, with a focus for CARIS 2 scaling incident prevention and detection as the Internet industry moves to a stronger and a more ubiquitous deployment of session encryption.

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This Internet-Draft will expire on 12 April 2021.

Table of Contents

1. Introduction

The Coordinating Attack Response at Internet Scale (CARIS) 2 workshop workshop [CARISEvent], sponsored by the Internet Society, took place 28 February and 1 March 2019 in Cambridge, Massachusetts, USA. Participants spanned regional, national, international, and enterprise Computer Security Incident Response Teams (CSIRT), operators, service providers, network and security operators, transport operators and researchers, incident response researchers, vendors, and participants from standards communities. This workshop continued the work started at the first CARIS workshop [RFC8073], with a focus for CARIS 2 on scaling incident prevention and detection as the Internet industry moves to a stronger and a more ubiquitous deployment of session encryption. Considering the related initiative to form a research group [SMART] in the Internet Research Task Force (IRTF) the focus on prevention included consideration of research opportunities to improve protocols and determine if there are ways to improve attack detection devleoped during the protocol design phase that could later influence protocol development in the IETF. This is one way to think about scaling response, through prevention and allowing for new methods to evolve for detection in a post-encrypted world. Although SMART has not progressed, the work to better scale incident response continues through the projects proposed at CARIS2 as well in future CARIS workshops.

2. Accepted Papers

Researchers from around the world submitted position and research papers summarizing key aspects of their work to help form the shared content of the workshop. The accepted papers may be found at workshop [CARISEvent], and include:

The program committee worked to fill in the agenda with meaningful and complementary sessions to round out the theme and encourage collaboration to advance research towards the goals of the workshop. These sessions included:

The presentations provided interesting background to familiarize workshop attendees with current research work, challenges that require addressing for forward progress, and opportunities to collaborate in the desire to better scale attack response and prevention.

3. CARIS2 Goals

The goal of each CARIS workshop has been to focus on the challenge of improving the overall security posture. The approach has been to identify intrinsic or built-in protection capabilities for improved defense, automation, and scaling attack response through collaboration and improved architectural patterns. It has been assumed that it is unlikely that additional training will address the lack of information security professionals to fill the job gap. Currently, there is approximately a 3 million person deficit [defecit] for security professionals worldwide and it's only expected to grow. In preparing for the workshop, the chair and programme committee considered that this gap cannot be filled through training, but the gap requires measures to reduce the number of information security professionals needed through new architectures and research towards attack prevention. CARIS 2 was specifically focused on the industry shift towards the increased use of stronger session encryption (TLSv1.3 [RFC8446], QUIC [I-D.ietf-quic-transport], TCPcrypt [RFC8548], etc.) and how prevention and detection can advance in this new paradigm. As such the goals for this workshop included:

4. Workshop Collaboration

Both CARIS workshops brought together a set of individuals who had not previously collaborated toward the goals of scaling attack response. This is important as the participants span various areas of Internet technology work, research, provide a global perspective, have access to varying data sets and infrastructure, and are influential in their area of expertise. The specific goals of the CARIS 2 workshop, contributions, and the participants were all considered in the design of the breakout sessions to both identify and advance research through collaboration. The breakout sessions varied in format to keep attendees engaged and collaborating, involving the full set of attendees and breakout groups.

The Workshop focused in trying to help identify potential areas for collaboration and advance research.  To do this, the workshop included 5 different breakout sessions focused on:

  1. Standardization and adoption: identify widely adopted and pervasive standard protocols and data formats as well as those that failed.
  2. Preventative Protocols and Scaling Defense: identify protocols to address automation at scale.
  3. Incident Response Coordination: brainstorm on what potential areas of research or future workshops could be held to improve on the scalability of incident response.
  4. Monitoring and Measurement:brainstorm on methods to perform monitoring and measurement with the heightened need and requirement to address privacy.
  5. Taxonomy and Gaps: brainstorm on away forward for the proposed SMART group

4.1. Breakout 1 Results: Standardization and Adoption

This breakout session considered points raised in the preceding talks on hurdles for automating security controls, detection, and response as the teams presenting noted several challenges they still face today. The breakout worked toward identifying standard protocols and data formats that succeeded in achieving adoption as well as several that failed or only achieved limited adoption. The results from the evaluation were interesting and could aid in achieving greater adoption when new work areas are developed. The results follow:

4.1.1. Wide adoption:

Secure Sockets Layer (SSL), now replaced by Transport Layer Security (TLS) protocol.

Observations: There was a clear need for session encryption at the transport layer to protect application data. eCommerce was a driving force at the time with a downside to those who did not adopt. Other positive attributes that aided adoption were modular design, clean interfaces, and being first to market.

Simple Network Management Protocol (SNMP) enables configuration management of devices with extension points for private configuration and management settings. SNMP is widely adopted and is only now after decades being replaced by a newer alternative, YANG (a data modeling language) facilitating configuration management via NETCONF or RESTCONF. The SNMP protocol facilitated an answer to a needed problem set: configuration, telemetry, and network management. It's development considered the connection between the user, vendor, and developers. Challenges did surface for adoption from SNMPv1.1 to 1.2, as there was no compelling reason for adoption. SNMPv3 gained adoption due to its resilience to attacks by providing protection through improved authentication and encryption.

IP Flow Information Export (IPFix) was identified as achieving wide adoption for several reasons. The low cost of entry, wide vendor support, diverse user base, and the wide set of use cases spanning multiple technology areas were some of the key drivers cited.

X.509 was explored for its success in gaining adoption. The solution being abstract from crypto, open, customizable, and extensible were some of the reasons cited for its successful adoption. The team deemed it a good solution to a good problem and observed that government adoption aided its success.

4.1.2. Limited Adoption

Next each team evaluated solutions that have not enjoyed wide adoption.

Although STIX and IODEF are somewhat similar in their goals, the standards were selected for evaluation by two separate groups with some common findings.

Structured Threat Information eXpression (STIX) has had limited adoption by the financial sector, but no single, definitive end user. The standard is still in development with the US government as the primary developer in partnership with OASIS. There is interest in using STIX to manage content, but users don't really care about what technology is used for the exchange. The initial goals may not wind up matching the end result for STIX as managing content may be the primary use case.

Incident Object Description Exchange Format (IODEF) was specified by national research and education networks (NREN) and computer security incident response teams (CSIRT) and formalized in the IETF. The user is the security operations center (SOC). While there are several implementations, it is not widely adopted. In terms of exchange, users are more interested in indicators than full event information and this applies to STIX as well. Sharing and trust are additional hurdles as many are not willing to disclose information.

DNS-based Authentication of Named Entities (DANE) has DNSsec as a dependency, which is a hurdle towards adoption (too many dependencies). It has a roll-your-own adoption model, which is risky. While there are some large pockets of adoption, there is still much work to do to gain widespread adoption. A regulatory requirement gave rise to partial adoption in Germany, which naturally resulted in production of documentation written in German - possibly giving rise to further adoption in German-speaking countries. There has also been progress made in the Netherlands through the creation of a website, The website allows you you to test your website for a number of standards (IPv6, DNSSEC, DANE etc.). is a collaboration of industry organizations, companies, and the government in the Netherlands, and is available for worldwide use.

IP version 6 (IPv6) has struggled and the expense of running a dual stack was one of the highest concerns on the list discussed in the workshop breakout. The end user for IPv6 is everyone and the breakout team considered it too ambiguous. Too many new requirements have been added over its 20 year life. The scope of necessary adoption is large with many peripheral devices. Government requirements for support have helped somewhat with improved interoperability and adoption, but features like NAT being added to IPv4 slowed adoption. With no new features being added to IPv4 and lessons learned, there's still a possibility for success.

4.2. Breakout 2 Results:Preventative Protocols and Scaling Defense

This next breakout followed the sessions on MUD, PAVA (Protocol for Automated Vulnerability Assessment), and PASC (Protocol for Automatic Security Configuration) which have themes of automation at scale. MUD was designed for IoT and as such, scaling was a major consideration. The PAVA and PASC work builds off of MUD and maintains some of the same themes. This next breakout was focused on groups brainstorming on preventative measures and enabling vendors to deploy mitigations.

One group dove a bit deeper into MUD and layer 2 (L2) discovery. MUD changes sets of filtering control management to the vendor or intermediary MUD vendors for a predictable platform that scales well. While the overall value of MUD is clear, the use of MUD and what traffic is expected for a particular device should be considered sensitive information as it could be used to exploit a device. MUD has an option of using L2 discovery to share MUD files. L2 discovery, like the dynamic host configuration protocol (DHCP) is not encrypted from the local client to the DHCP server at this point in time (there is some interest to correct this, but it hasn't received enough support yet). As a result, it is possible to leak information and reveal data about the devices for which the MUD files would be applied. This could multicast out information such as network characteristics, firmware versions, manufacturer, etc. There was some discussion on the use of 802.11 to improve connections. Several participants from this group planned to research this further and identify options to prevent information leakage while achieving the stated goals of MUD.

The next group discussed a proposal one of the participants had already begun developing, namely privacy for rendezvous service. The basic idea was to encrypt SNI using DNS to obtain public keys. The suffix on server IPv6 would be unique to a TLS session (Information missing). The discussion on this proposal was fruitful as the full set of attendees engaged, with special interest from the incident responders to be involved in early review cycles. Incident responders are very interested to understand how protocols will change and to assess the overall impact of changes on privacy and security operations. Even if there are no changes to the protocol proposals stemming from this review, the group discussion landed on this being a valuable exchange to understand early the impacts of changes for incident detection and mitigation, to devise new strategies and to provide assessments on the impact of protocol changes on security in the round.

The third group reported back on trust exchanges relying heavily on relationships between individuals. They were concerned with scaling the trust model and finding ways to do that better. The third breakout dove deeper into this topic.

The fourth breakout group discussed useful data for incident responders. This built on the first breakout session. The group determined that indicators of compromise (IOCs) are what most organizations and groups are able to successfully exchange. Ideally, these would be fixed and programmable. They discussed developing a richer event threat sharing format. When reporting back to the group, a successful solution used in the EU was mentioned, Malware Information Sharing Platform (MISP) [MISP]. This will be considered in their review of existing efforts to determine if anything new is needed.

4.3. Breakout 3 Results: Incident Response Coordination

Incident response coordination currently does not scale. This breakout session focused on brainstorming on incident response and coordination, looking specifically at what works well for teams today, what is holding them back, and what risks loom ahead. Output from this session could be used to generate research and to dive deeper in a dedicated workshop on these topics.


Creating Drag:

Looming problems:

4.4. Breakout 4 Results: Monitoring and Measurement

The fourth breakout followed Dave Plonka's talk on IPv6 aggregation to provide privacy for IPv6 sessions. Essentially, IPv6 provides additional capabilities for monitoring sessions end-to-end. Dave and his co-author Arthur Berger primarily focus on measurement research, but found a way to aggregate sessions to assist with maintaining user privacy. If you can devise methods to perform management and measurement, or even perform security functions, while accommodating methods to protect privacy, a stronger result is likely. This also precludes the need for additional privacy improvement work to defeat measurement objectives.

This breakout was focused on devising methods to perform monitoring and measurement, coupled with advancing privacy considerations. The full group listed out options for protocols to explore and ranked them, with the 4 highest then explored by the breakout groups. Groups agreed to work further on the proposed ideas.

4.4.1. IP Address Reputation

There is a need to understand address assignment and configuration for hosts and services, especially with IPv6 [PlonkaBergerCARIS2] in (1) sharing IP address-related information to inform attack response efforts, while still protecting the privacy of victims and possible attackers, and (2) mitigating abuse by altering the treatment, e.g., dropping or rate-limiting, of packets. Currently, there is no database for analysts and researchers can consult to, for instance, determine to lifetimes of IPv6 addresses or the prefix length at which the address is expected to be stable over time. The researchers propose either introduce a new database (compare PeerdingDB) or extending existing databases (e.g., the RIRs'), to contain such information and allowing arbitrary queries. The prefix information would either be provided by networks, who are willing, or based on measurement algorithms that reverse-engineer reasonable values based on Internet measurements [PlonkaBergerKIP]. In the former case, the incentive of networks to provide such information is to so that privacy of their users is respected and to limit collateral damage caused by access control lists affecting more of that network's addresses than necessary, e.g., in the face of abuse. This is an early idea, the lead to contact if interested to help develop this further is Dave Plonka.

4.4.2. Server Name Authentication Reputation C (SNARC)

SNARC is a mechanism to assign value to trust indicators, used to make decisions about good or bad actors. The mechanism would be able to distinguish between client and server in connections, would be human readable, builds on zero trust networking, and avoids consolidation supporting legitimate new players. The group planned to research visual aspects and underlying principles as they begin work on this idea. SNARC has a similar theme to the IP reputation/BGP ranking idea mentioned above. An RFC would help customers and design team on existing solutions. They planned to begin work in several stages, researching "trust" indicators, "trust" value calculations, and research actions to apply to "trust". The overarching goal is to address blind trust, one of the challenges identified with information/incident exchanges. If interested to work further with this team, the lead contact is: Trent Adams.

4.4.3. Logging

The breakout group presented the possibility of injecting logging capabilities at compile time for applications, resulting in a more consistent set of logs, covering an agreed set of conditions. If the log-injecting compiler were used this would increase logging for those applications and improve the uniformity of logged activity. Increasing logging capabilities at the endpoint is necessary as the shift towards increased use of encrypted transport continues. The lead for contact if interested to develop this further is Nalini Elkins.

4.4.4. Fingerprinting

Fingerprinting has been used for numerous applications on the web, including security, and will become of increasing importance with the deployment of stronger encryption. This provides a method to identify traffic without using decryption. The group discussed privacy considerations and balancing how you achieve the security benefits (identifying malicious traffic, information leakage, threat indicators, etc.). They are interested to derive methods to validate the authenticity without identifying the source of traffic. They are also concerned with scaling issues. If interested to work further with this team, the lead contact is: William Weinstein.

4.5. Taxonomy and Gaps Session

At the start of day 2, Kirsty Paine and Mirjam Kuhne prepared and Kirsty led a workshop style session to discuss taxonomies used in incident response, attacks, and threat detection, comparing solutions and identifying gaps. The primary objective was to determine a path forward selecting language to be used in the proposed SMART group. Several taxonomies were presented for review and discussion. The topic remains open, the following key points were highlighted by participants:

The result of this discussion was not to narrow down to one taxonomy, but to think about mappings between taxonomies and the use cases for exchanging or sharing information, eventually giving rise to a common method to discuss threats and attacks. Researchers need a common vocabulary, not necessarily a common taxonomy.

5. Next Steps

The next steps from the CARIS2 workshop are twofold.

6. Summary

Wrapping up the workshop, we reviewed the list of agreed projects to get a feel for actual interest as a follow up. Through the course of the 2-day workshop, a larger set of potential research items had been generated, and this gave participants a chance to reassess commitments to better have them match expected outcomes. The highest ranking projects in terms of interest to drive the ideas forward included the following:

7. Security Considerations

There are no security considerations as this is an informational workshop summary report.

8. IANA Considerations

This memo includes no request to IANA.

9. Acknowledgements

Thank you to each of the CARIS2 participants who brought their ideas, energy and willingness to collaborate to advance attack response at Internet scale.

A big thank you to each member of the program committee for your review of program materials, papers, and guidance on the workshop format: Mat Ford, Internet Society, UK, Jamie Gillespie, APNIC, AU, Chris Inacio, CERT/CC, US, Mirja Kuhlewind, ETH Zurich, CH, Mirjam Kuhne, RIPE NCC, NL, Carlos Martinez, LACNIC, UY, Kathleen M. Moriarty, Dell EMC (Chair), Kirsty Paine, NCSC, UK, and Takeshi Takahashi, NICT, JP.

Thank you to Megan Hyland, DellEMC, for her review and guidance on the breakout session format and tools to enable successful collaboration.

Thank you to the minute takers, Akashaya Khare and Thinh Nguyen, DellEMC OCTO Cambridge Dojo team.

10. References

10.1. Informative References

Moriarty, K. and M. Ford, "Coordinating Attack Response at Internet Scale (CARIS) Workshop Report", RFC 8073, DOI 10.17487/RFC8073, , <>.
Shirey, R., "Internet Security Glossary, Version 2", FYI 36, RFC 4949, DOI 10.17487/RFC4949, , <>.
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <>.
Bittau, A., Giffin, D., Handley, M., Mazieres, D., Slack, Q., and E. Smith, "Cryptographic Protection of TCP Streams (tcpcrypt)", RFC 8548, DOI 10.17487/RFC8548, , <>.
Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage Description Specification", RFC 8520, DOI 10.17487/RFC8520, , <>.
Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed and Secure Transport", Work in Progress, Internet-Draft, draft-ietf-quic-transport-31, , <>.

10.2. URL References

Internet Society, "CARIS Event Information and Accepted Papers", .
IETF, "Interface to Network Security Functions (i2nsf)".
Morgan, S., "Cybersecurity Talent Crunch To Create 3.5 Million Unfilled Jobs Globally By 2021".
[MISP], "Malware Information Sharing Platform", .
IRTF, "Stopping Malware and Researching Threats", .
CARIS2, "CARIS2 Paper Submission,", .
Arxiv, "kIP: a Measured Approach to IPv6 Address Anonymization", .

Author's Address

Kathleen M Moriarty
Dell Technologies
176 South Street
Hopkinton, MA 01748
United States