Script updating gh-pages from 7966334. [ci skip]

draft-dekater-scion-pki-04/draft-dekater-scion-pki.txt → cdk-security-considerations/draft-dekater-scion-pki.txt

@@ -5,7 +5,7 @@
 Network Working Group                                        C. de Kater
 Internet-Draft                                             N. Rustignoli
 Intended status: Informational                         SCION Association
-Expires: 24 March 2024                                 21 September 2023
+Expires: 1 June 2024                                    29 November 2023
 
 
                         SCION Control-Plane PKI
@@ -56,7 +56,7 @@ Status of This Memo
    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 24 March 2024.
+   This Internet-Draft will expire on 1 June 2024.
 
 Copyright Notice
 
@@ -109,6 +109,9 @@ Table of Contents
        4.2.2.   Verifying a Control-Plane Message
      4.3.  Creating a New Control-Plane AS Certificate
    5.  Security Considerations
+     5.1.  Local ISD Kill Switch
+     5.2.  Remote ISD/AS Kill Switch
+     5.3.  Recovery from Kill Switches
    6.  IANA Considerations
    7.  References
      7.1.  Normative References
@@ -2384,8 +2387,102 @@ Table of Contents
 
 5.  Security Considerations
 
-   The entire document is about security considerations.  More details
-   will follow in future versions of this draft.
+   This section describes the possible security risks and attacks that
+   SCION's control-plane PKI may be prone to, and how these may be
+   mitigated.  The focus lies on _inter_-AS routing: SCION does not
+   solve intra-AS routing issues, nor does it provide end-to-end payload
+   encryption, and identity authentication.  These topics lie therefore
+   outside the scope of this section.
+
+   As described above, the SCION's control-plane PKI handles
+   cryptographic material and lays the foundation for the authentication
+   procedures in SCION.  It is used by SCION's control plane to
+   authenticate and verify path information, and builds the basis for
+   SCION's special trust model based on the Isolation Domains (ISDs).
+   The CP-PKI provides each AS within a specific ISD with a certified
+   key pair.  These keys enable the authentication of all routing
+   messages - every AS and end host can verify all routing messages by
+   following the certificate chain.
+
+   SCION’s trust architecture fundamentally differs from a global
+   monopolistic trust model.  In SCION, each ISD manages its own trust
+   roots instead of a single global entity providing those roots.  This
+   structure gives each ISD autonomy in terms of key management and in
+   terms of trust.  This prevents SCION from the occurrence of a global
+   kill switch affecting all ISDs at once.  However, local kill switches
+   are to some extent still possible in SCION.  The following sections
+   explain these cases and possible countermeasures.
+
+   *Note:* This section only discusses security considerations related
+   to SCION's control-plane PKI.  For SCION control plane- and routing-
+   specific security considerations, see [I-D.scion-cp].  [I-D.scion-dp]
+   includes security considerations that concern the SCION data plane
+   and data forwarding.
+
+5.1.  Local ISD Kill Switch
+
+   As in the case of DNSSEC and BGPsec, executing a kill switch inside a
+   local ISD can be done at different levels of the AS-level hierarchy.
+   One difference in SCION is that core ASes cannot be switched off by a
+   parent authority since they manage their own cryptographic trust
+   roots.  Another difference is that the attack vector of intra-ISD
+   kill switches has only two entry levels; all ASes obtain certificates
+   directly from the CAs included in the TRC.
+
+   If one of the core’s root keys is compromised, an adversary could
+   issue illegitimate AS certificates, which may be used in further
+   attacks.  However, multiple different voting keys (defined by the
+   voting quorum) would be required to maliciously change the TRC
+   through a TRC update.
+
+   Moreover, the core might stop propagating PCBs, precluding the
+   discovery of new paths.  In this case, downstream ASes will notice
+   that PCBs are no longer being propagated, but all previously
+   discovered (and still valid) paths are still usable for data-plane
+   forwarding until they expire.
+
+   Perhaps a more stealthy kill switch would be to shut down path
+   services in victim ASes.  While this cannot be done remotely, an
+   adversarial entity controlling an ISD (e.g., a government) might
+   compel core and non-core ASes to stop replying to path requests.
+   Alternatively, the compelled ASes might return only a subset of all
+   available paths.  If this attack were used in conjunction with
+   blackholing, senders in the ISD would have difficulty getting traffic
+   out of the ISD.  However, note that in SCION, existing paths can
+   continue to be used in the data plane as long as the traversed ASes
+   allow the forwarding.
+
+5.2.  Remote ISD/AS Kill Switch
+
+   SCION ISDs independently manage their own cryptographic keys and
+   namespace.  This prevents a remote attacker who is outside the
+   victim's ISD from causing a kill switch in the victim ISD.  That is,
+   without access to the private keys forming the trust root in the
+   remote ISD, the attacker is limited to data-plane attacks.  Even if
+   private keys became available to a remote attacker, they would need
+   access to an AS inside the remote ISD to inject faulty information.
+
+5.3.  Recovery from Kill Switches
+
+   In the event of a key compromise of a non-core AS, the impacted AS
+   needs to obtain a new certificate from the core.  This process will
+   vary depending on internal issuance protocols.  If any of the root
+   keys or voting keys contained in the TRC are compromised, the TRC
+   must be updated as described in Section 3.1.5.  Only in the case of a
+   catastrophic compromise of multiple voting keys at the same time must
+   a trust reset be triggered.
+
+   If the core AS has not been compromised, but is instead acting
+   maliciously (e.g., by not propagating PCBs downstream or tampering
+   with responses for paths or certificates), one way to recover is for
+   downstream ASes to self- organize and form a new ISD.  By now
+   operating autonomously, the new ISD can begin path discovery and
+   traffic forwarding.
+
+   SCION, unlike BGP, has no notion of routing convergence.  Instead,
+   the flooding of PCBs disseminates topology information.  This means
+   that in the worst case, if all paths must be re-created, fresh paths
+   are established after a single flood has reached all ASes.
 
 6.  IANA Considerations
 
@@ -2453,6 +2550,16 @@ Table of Contents
               Analysis", 2022, <https://datatracker.ietf.org/doc/draft-
               rustignoli-panrg-scion-components/>.
 
+   [I-D.scion-cp]
+              de Kater, C., Rustignoli, N., and M. Frei, "SCION Control
+              Plane", 2023, <https://datatracker.ietf.org/doc/draft-
+              dekater-scion-controlplane/>.
+
+   [I-D.scion-dp]
+              de Kater, C. and N. Rustignoli, "SCION Data Plane", 2023,
+              <https://datatracker.ietf.org/doc/draft-dekater-scion-
+              dataplane/>.
+
    [I-D.scion-overview]
               de Kater, C., Rustignoli, N., and A. Perrig, "SCION
               Overview", 2022, <https://datatracker.ietf.org/doc/draft-

draft-dekater-scion-pki-04/index.html → cdk-security-considerations/index.html

@@ -1,7 +1,7 @@
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-    <title>scionassociation/scion-cppki_I-D draft-dekater-scion-pki-04 preview</title>
+    <title>scionassociation/scion-cppki_I-D cdk-security-considerations preview</title>
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-    <h1>Editor's drafts for draft-dekater-scion-pki-04 branch of <a href="https://github.com/scionassociation/scion-cppki_I-D/tree/draft-dekater-scion-pki-04">scionassociation/scion-cppki_I-D</a></h1>
-    <table id="branch-draft-dekater-scion-pki-04">
+    <h1>Editor's drafts for cdk-security-considerations branch of <a href="https://github.com/scionassociation/scion-cppki_I-D/tree/cdk-security-considerations">scionassociation/scion-cppki_I-D</a></h1>
+    <table id="branch-cdk-security-considerations">
       <tr>
         <td><a href="./draft-dekater-scion-pki.html" class="html draft-dekater-scion-pki" title="SCION Control-Plane PKI (HTML)">SCION CP-PKI</a></td>
         <td><a href="./draft-dekater-scion-pki.txt" class="txt draft-dekater-scion-pki" title="SCION Control-Plane PKI (Text)">plain text</a></td>