Tackling Pervasive Surveillance or How to improve Security of the Internet?
draft-tschofenig-perpass-surveillance-00
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Author | Hannes Tschofenig | ||
| Last updated | 2013-10-21 | ||
| Stream | (None) | ||
| Formats | plain text xml htmlized pdfized bibtex | ||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-tschofenig-perpass-surveillance-00
PERPASS H. Tschofenig
Internet-Draft
Intended status: Informational October 21, 2013
Expires: April 24, 2014
Tackling Pervasive Surveillance or How to improve Security of the
Internet?
draft-tschofenig-perpass-surveillance-00.txt
Abstract
Surveillance is the observation or monitoring of an individual's
communications or activities. Surveillance is one of several privacy
/security threats engineers try to take into account in their
designs. The reports about pervasive monitoring of Internet traffic
have, however, surprised many since the scale was not envisaged
during the design of many Internet protocols. The approach to get
access to meta-data as well as to communication content has taken
forms that are largely indistinguishable from ordinary attacks.
This document explains the attacks in context of the larger Internet
eco-system.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 24, 2014.
Copyright Notice
Copyright (c) 2013 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
Tschofenig Expires April 24, 2014 [Page 1]
Internet-Draft Tackling Pervasive Surveillance October 2013
(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. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Attack Surface . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Cryptographic Primitives . . . . . . . . . . . . . . . . 3
2.2. Protocols and Architecture . . . . . . . . . . . . . . . 4
2.3. Implementations . . . . . . . . . . . . . . . . . . . . . 5
2.4. Deployment . . . . . . . . . . . . . . . . . . . . . . . 5
3. Security Considerations . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
6. Normative References . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Securing the Internet is a rather complicated task since the threat
landscape has changed significantly over the last 20 years. For many
of the recognized security weaknesses solutions have been developed
and standardized. Unfortunately, the existence of specifications by
itself is not enough: security protocols need to be implemented and
deployed. Since many of the tougher security challenges suffer from
a collective action problem it typically takes many years until
widespread deployment has been reached (typically requiring
sufficient energy and enough pain). The recently observed pervasive
monitoring activities represent a new challenge to the Internet
community and require us to review and revisit some earlier made
design decisions.
To fully understand the role of the IETF in this context it is useful
to look at the types of attacks that are occuring. It quickly
becomes clear that the responsiblities for developing countermeasures
resides not only with the IETF but with the larger Internet eco-
system.
Tschofenig Expires April 24, 2014 [Page 2]
Internet-Draft Tackling Pervasive Surveillance October 2013
2. Attack Surface
The attack surface is categorized into four areas, as shown in Figure
1. In subsequent sections more details are provided and examples are
listed.
+-----------------+ +---------------+ +----------------+ +------------+
| | | | | | | |
| Aging or Broken | | Weak | | Implementation | | Insecure |
| Cryptographic | | Protocol or | | Bugs and other | | Deployment |
| Primitives | | Architectural | | Vulnerabilities| | Practices |
| | | Foundation | | | | |
+-----------------+ +---------------+ +----------------+ +------------+
Figure 1: Attack Surface.
2.1. Cryptographic Primitives
Internet security relies on sound cryptographic primitives, such as
hash functions, random number generators, integrity and encryption
algorithms, etc. The basic design philosophy is that the strength of
keyed algorithms relies on the length of the secret key. It is well-
known that these cryptographic primitives "age" as processing power
of computing hardware increases. This means that over time it is
faster to search through the entire key space with the same amount of
financial budget spent. Researchers have also made improvements in
analysing the building blocks of these algorithms and new attack
techniques (such as side channel attacks). This has lead to a
continued development of new cryptographic primitives.
The IETF has played a minor role in the work on cryptographic
primitives. Instead, it has rather been a consumer of these building
blocks and has therefore relied on others to select specifications
and to provide guidance. As an exception one could see the
publication of HMAC [21]. In fact, the crypto-community world-wide
is rather small and for a variety of reasons the National Institute
of Standards and Technology (NIST) has spearheaded many of these
developments. The IETF security community has relied on NIST to
provide guidance largely because no other groups have come forward to
offer advice.
While there have been problems with weaknesses in cryptographic
primitives (e.g., RC4 [1], [2], [3]) those have not been a a
substantial issue from a standardization point of view thanks to
'crypto-aglity'. Crypto-agility is the ability of a protocol to
adapt to evolving cryptographic algorithms and security requirements.
Tschofenig Expires April 24, 2014 [Page 3]
Internet-Draft Tackling Pervasive Surveillance October 2013
This may include the provision of a modular mechanism to allow
cryptographic algorithms to be updated without substantial disruption
to deployed implementations.
Problematic are, however, potential backdoors in elliptic curve
cryptography as well [9]. While the ability of many IETF protocols
to negotiate cryptographic protocols allows to deal with weak
cryptographic algorithm there is still some degree of uncertainty
about what algorithms are 'safe' to use.
2.2. Protocols and Architecture
Internet protocols and communication architectures belong to the core
expertise of the IETF and a lot of work has been done in this regard.
The IETF security community has been established after security
considerations sections became a mandatory part of IETF
specifications [22] and the overall understanding of security is
fairly large thanks to education efforts, the security area
directorate, and the push back from the IESG when questionalble
documents arrive. Still, there are a number of challenges. For
example, cryptographic attacks like BEAST [5], CRIME [6], and Lucky
Thirteen [4] targeted the Transport Layer Security (TLS) protocol.
More difficult to deal with are security and privacy challenges with
entire architectures, as the design of email, instant messaging,
voice over IP (VoIP), DNS, DHCP, and other protocols demonstrate.
Section 8 of [20] provides an interesting summary of the design
tradeoffs that had been made in the real-time communication
architecture as used by VoIP and instant messaging. The difficulty
is often not in crafting a security at the level of a single
specification but rather to ensure that the protocol development of
an entire communication architecture provides good security and
privacy properties after 10+ years of standardization when various
different industry trends (such as cloud computing, and the
JavaScript-based Web), and the interests of participating parties
collide. In many cases, the design decisions are subtle. For
example, the excitement of Web companies to use HTTP cookies [23] as
a replacement for cryptographic authentication was hard to
anticipate. The large number of key exchange mechanisms standardized
for VoIP might have confused the industry [17], [18], [16].
Often, insecure versions of a protocol are standardized and completed
first before the secure version is developed. For example, consider
security for HTTP, SIP, XMPP, eMail, etc. While this may not have a
consequence on paper it certainly impacts follow-up implementations
and deployments.
Improving security and privacy for different communication protocols
has been subject of discussion on the IETF perpass list [10]. Note
Tschofenig Expires April 24, 2014 [Page 4]
Internet-Draft Tackling Pervasive Surveillance October 2013
that some discussions go beyond suggesting actions for the IETF but
rather belong the discussion in Section 2.3 and Section 2.4. As
another example of ongoing work is a document on best current
practices for Transport Layer Security [19], which gathers experience
from recent security attacks and recommends state-of-the-art
ciphersuites. The limitations of the public key infrastructure that
had gotten a lot of attention around 2011: DigiNotar, a Dutch
certificate authority, had a security breach and in the same year a
Comodo affiliate was compromised. Both cases lead to fraudulent
issue of certificates. The same structural vulnerability has been
exploided by the NSA in man-in-the-middle attacks [15].
2.3. Implementations
Once standardization work is completed the specifications have to get
implemented. Often those who develop the specifications are not
necessary the same parties that implement the software. The
specifications therefore have to offer enough context and be readable
to avoid security problems via misinterpretation. Also, those who
implement and those who deploy are also not necessarily the same set
of people. For example, some developers write open source libraries
useful for a wide range of communities, as it is the case with
OpenSSL or GnuTLS.
Implementations may show a number of security weaknesses, such as
lack of security features, quality of the implementations (e.g.,
implementations with insufficent penetration testing), weak pseudo-
random number generators [7], [11], etc. Since the source code of
many implementations is not available to the public backdoors may be
built-in [8].
Many implementations of Web applications, however, suffer from basic
vulnerabilities (such as injection or cross-site scripting attacks),
as the top-10 charts of the Open Web Application Security Project
(OWASP) reveal [13]. Sometimes vendors make design decision for
their product implementations that lead to security vulnerabilities,
for example when devices are shipped with default-passwords or with
enabled debugging interfaces [14].
2.4. Deployment
Finally, the implementations of various protocols are put together
and complete systems are deployed. Those who deploy have to make
various decisions that go beyond pure protocol aspects but also have
to consider various configuration options. These deployment
decisions have an important impact on the provided privacy and
security properties. Examples include, backend server protocols
secured only with "physical security" (i.e., without cryptographic
Tschofenig Expires April 24, 2014 [Page 5]
Internet-Draft Tackling Pervasive Surveillance October 2013
security protection), email services without TLS protection, custom
security designs (see, for example, WhatsApp [12]), etc. With the
juridiction the service is provided in certain responsiblities for
data retention, and lawful intercept arise.
3. Security Considerations
This entire document focused on the discussion of new functionality
for securing Diameter AVPs selectively between non-neighboring nodes.
4. IANA Considerations
This document does not require actions by IANA.
5. Acknowledgments
We would like to thank the IAB for encouraging me to turn my slide
deck into a document.
6. Normative References
[1] Fluhrer, S., Mantin, I., and A. Shamir, "Weaknesses in the
Key Scheduling Algorithm of RC4", Selected Areas in
Cryptography , 2001.
[2] ISOBE, T., OHIGASHI, T., WATANABE, Y., and M. MORII, "Full
Plaintext Recovery Attack on Broadcast RC4", International
Workshop on Fast Software Encryption , 2013.
[3] AlFardan, N., Bernstein, D., Paterson, K., Poettering, B.,
and J. Schuldt, "On the Security of RC4 in TLS", Usenix
Security Symposium 2013, 2013, <https://www.usenix.org/
conference/usenixsecurity13/security-rc4-tls>.
[4] AlFardan, N. and K. Paterson, "Lucky Thirteen: Breaking
the TLS and DTLS Record Protocols", IEEE Symposium on
Security and Privacy , 2013.
[5] Rizzo, J. and T. Duong, "Browser Exploit Against SSL/TLS",
2011, <http://packetstormsecurity.com/files/105499/
Browser-Exploit-Against-SSL-TLS.html>.
[6] Rizzo, J. and T. Duong, "The CRIME Attack", EKOparty
Security Conference 2012, 2012.
Tschofenig Expires April 24, 2014 [Page 6]
Internet-Draft Tackling Pervasive Surveillance October 2013
[7] Ars Technica, "Stop using NSA-influenced code in our
products, RSA tells customers", URL: http://
arstechnica.com/security/2013/09/stop-using-nsa-influence-
code-in-our-product-rsa-tells-customers/, Sep 2013.
[8] Boing Boing, "Anti-Tor malware reported back to the NSA",
URL: http://boingboing.net/2013/08/05/anti-tor-malware-
reported-back.html, Aug 2013.
[9] Cryptography Stack Exchange, "Should we trust the NIST-
recommended ECC parameters?", URL: http://
crypto.stackexchange.com/questions/10263/should-we-trust-
the-nist-recommended-ecc-parameters, Sep 2013.
[10] Nadia Heninger, "PERPASS Mailing List", URL: http://
www.ietf.org/mail-archive/web/perpass/current/
maillist.html, Oct 2013.
[11] IETF, "New research: There's no need to panic over
factorable keys-just mind your Ps and Qs", URL: https
://freedom-to-tinker.com/blog/nadiah/new-research-theres-
no-need-panic-over-factorable-keys-just-mind-your-ps-and-
qs/, Oct 2013.
[12] fileperms Blog, "WhatsApp is broken, really broken", URL:
http://fileperms.org/whatsapp-is-broken-really-broken/,
Sep 2012.
[13] OWASP, "Open Web Application Security Project (OWASP): Top
Ten Project", URL: https://www.owasp.org/index.php/
Category:OWASP_Top_Ten_Project, Oct 2013.
[14] Wired, "NSA Laughs at PCs, Prefers Hacking Routers and
Switches", URL: http://www.wired.com/threatlevel/2013/09/
nsa-router-hacking/, Apr 2013.
[15] Zeljka Zorz, "NSA impersonated Google in MitM attacks",
URL: https://www.net-security.org/secworld.php?id=15579,
Apr 2013.
[16] Westerlund, M. and C. Perkins, "Options for Securing RTP
Sessions", draft-ietf-avtcore-rtp-security-options-08
(work in progress), October 2013.
[17] Wing, D., Fries, S., Tschofenig, H., and F. Audet,
"Requirements and Analysis of Media Security Management
Protocols", RFC 5479, April 2009.
Tschofenig Expires April 24, 2014 [Page 7]
Internet-Draft Tackling Pervasive Surveillance October 2013
[18] Perkins, C. and M. Westerlund, "Securing the RTP Protocol
Framework: Why RTP Does Not Mandate a Single Media
Security Solution", draft-ietf-avt-srtp-not-mandatory-14
(work in progress), October 2013.
[19] Sheffer, Y. and R. Holz, "Recommendations for Secure Use
of TLS and DTLS", draft-sheffer-tls-bcp-01 (work in
progress), September 2013.
[20] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973, July
2013.
[21] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104, February
1997.
[22] Postel, J., "Instructions to RFC Authors", RFC 1543,
October 1993.
[23] Tschofenig, H., Turner, S., and M. Hanson, "An Inquiry
into the Nature and the Causes of Web Insecurity", draft-
tschofenig-secure-the-web-04 (work in progress), October
2012.
Author's Address
Hannes Tschofenig
Email: Hannes.Tschofenig@gmx.net
URI: http://www.tschofenig.priv.at
Tschofenig Expires April 24, 2014 [Page 8]