Network Working Group Luyuan Fang Internet Draft Cisco Systems Intended status: Informational Ben Niven-Jenkins Expires: January 12, 2011 Velocix Raymond Zhang BT Nabil Bitar Verizon July 12, 2010 Security Framework for MPLS-TP draft-fang-mpls-tp-security-framework-02.txt Abstract This document provides a security framework for Multiprotocol Label Switching Transport Profile (MPLS-TP). MPLS-TP Requirements and MPLS-TP Framework are defined in [RFC 5654] and [RFC 5921]. Extended from MPLS technologies, MPLS-TP introduces new OAM capabilities, transport oriented path protection mechanism, and strong emphasis on static provisioning supported by network management systems. This document addresses the security aspects that are relevant in the context of MPLS-TP specifically. It describes the security requirements for MPLS-TP; potential securities threats and migration procedures for MPLS-TP networks and MPLS-TP inter-connection to MPLS, GMPLS networks. The general security analysis and guidelines for MPLS and GMPLS are addressed in [FRC 5920], will not be covered in this document. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. [Page 1] MPLS-TP Security framework July 2010 The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 12, 2011. Copyright Notice Copyright (c) 2010 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. 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. 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..............................................3 1.1. Background and Motivation..............................3 1.2. Scope..................................................4 1.3. Terminology............................................5 1.4. Structure of the document..............................6 2. Security Reference Models.................................6 2.1. Security Reference Model 1.............................7 2.2. Security Reference Model 2.............................8 3. Security Requirements for MPLS-TP........................11 3.1. Protection within the MPLS-TP Network ................11 4. Security Threats.........................................13 4.1. Attacks on the Control Plane..........................15 [Page 2] MPLS-TP Security framework July 2010 4.2. Attacks on the Data Plane.............................15 5. Defensive Techniques for MPLS-TP Networks ...............16 5.1. Authentication .......................................16 5.2. Access Control Techniques.............................17 5.3. Use of Isolated Infrastructure........................18 5.4. Use of Aggregated Infrastructure......................18 5.5. Service Provider Quality Control Processes............18 5.6. Verification of Connectivity..........................18 6. Monitoring, Detection, and Reporting of Security Attacks.18 7. Security Considerations..................................19 8. IANA Considerations......................................19 9. Normative References.....................................19 10. Informative References.................................20 11. Author's Addresses.....................................20 Requirements Language Although this document is not a protocol specification, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC 2119]. 1. Introduction 1.1. Background and Motivation This document provides a security framework for Multiprotocol Label Switching Transport Profile (MPLS-TP). MPLS-TP Requirements and MPLS-TP Framework are defined in [RFC 5654] and [RFC 5921]. The intent of MPLS-TP development is to address the needs for transport evolution, the fast growing bandwidth demand accelerated by new packet based services and multimedia applications, from Ethernet Services, Layer 2 and Layer 3 VPNS, triple play to Mobile Access Network (RAN) backhaul, etc. MPLS-TP is based on MPLS technologies to take advantage of the technology maturity, and it is required to maintain the transport characteristics. Focused on meeting the transport requirements, MPLS-TP uses a subset of MPLS features, and introduces extensions to reflect the transport technology characteristics. The added functionalities [Page 3] MPLS-TP Security framework July 2010 include in-band OAM, transport oriented path protection and recovery mechanisms, etc. There is strong emphasis on static provisioning supported by Network Management System (NMS) or Operation Support System (OSS). Of course, there are needs for MPLS-TP and MPLS interworking. The security aspects for the new extensions which are particularly designed for MPLS-TP need to be addressed. The security models, requirements, threat and defense techniques previously defined in [RFC 5920] can be used for the re-use of the existing functionalities in MPLS and GMPLS, but not sufficient to cover the new extensions. 1.2. Scope This document addresses the security aspects that are specific to MPLS-TP. It intends to provide the security requirements for MPLS- TP; defines security models which apply to various MPLS-TP deployment scenarios; identifies the potential securities threats and migration procedures for MPLS-TP networks and MPLS-TP inter- connection to MPLS, GMPLS networks. Inter-AS and Inter-provider security for MPLS-TP to MPLS-TP connections or MPLS-TP to MPLS connections are discussed, where connections present higher security risk factors than connections for Intra-AS MPLS-TP. The general security analysis and guidelines for MPLS and GMPLS are addressed in [RFC 5920], the content which has no new impact to MPLS-TP will not be repeated in this document. Other general security issues regarding transport networks but not specific to MPLS-TP is out of scope as well. Readers may also refer to the "Security Best Practices Efforts and Documents" [opsec effort] and "Security Mechanisms for the Internet" [RFC3631] (if there are linkage to internet in the applications) for general network operation security considerations. This document does not intend to define the specific mechanisms/methods which must be implemented to satisfy the security requirements. Issues/Areas to be addressed: G-Ach (control plane attack, DoS attack, message intercept, etc.) Spoofing ID Loopback NMS attack NMS and CP interaction MIP/MEP assignment and attacks Topology discovery Data plane authentication [Page 4] MPLS-TP Security framework July 2010 Label authentication DoS attack in Data Plane Performance Monitoring This draft is work in progress. 1.3. Terminology This document uses MPLS, MPLS-TP, and Security specific terminology. Detailed definitions and additional terminology for MPLS-TP may be found in [RFC 5654], [RFC 5921], and MPLS/GMPLS security related terminology in [RFC 5920]. Term Definition ---------------------------------------------------- APS Automatic Protection Switching ATM Asynchronous Transfer Mode BFD Bidirectional Forwarding Detection CE Customer-Edge device CM Configuration Management CoS Class of Service CPU Central Processing Unit DNS Domain Name System DoS Denial of Service EMF Equipment Management Function ESP Encapsulating Security Payload FEC Forwarding Equivalence Class FM Fault Management GAL Generic Alert Label G-ACH Generic Associated Channel GMPLS Generalized Multi-Protocol Label Switching GCM Galois Counter Mode IKE Internet Key Exchange LDP Label Distribution Protocol LMP Link Management Protocol LSP Label Switched Path MD5 Message Digest Algorithm MEP Maintenance End Point MIP Maintenance Intermediate Point MPLS MultiProtocol Label Switching NTP Network Time Protocol OAM Operations, Administration, and Management PE Provider-Edge device PM Performance Management PSN Packet-Switched Network [Page 5] MPLS-TP Security framework July 2010 PW Pseudowire QoS Quality of Service RSVP Resource Reservation Protocol RSVP-TE Resource Reservation Protocol with Traffic Engineering Extensions SCC Signaling Communication Channel SDH Synchronous Digital Hierarchy SLA Service Level Agreement SNMP Simple Network Management Protocol SONET Synchronous Optical Network S-PE Switching Provider Edge SRLG Shared Risk Link Group SSH Secure Shell SSL Secure Sockets Layer SYN Synchronize packet in TCP TCP Transmission Control Protocol TDM Time Division Multiplexing TE Traffic Engineering TLS Transport Layer Security TTL Time-To-Live T-PE Terminating Provider Edge UDP User Datagram Protocol VPN Virtual Private Network WG Working Group of IETF WSS Web Services Security 1.4. Structure of the document Section 1: Introduction Section 2: MPLS-TP Security Reference Models Section 3: Security Requirements Section 4: Security threats Section 5: Defensive/mitigation techniques/procedures Note that this document is currently work in progress, not all requirements and security discussions are included, and some sections will be filled in later revision. 2. Security Reference Models This section defines a reference model for security in MPLS-TP networks. The models are built on the architecture of MPLS-TP defined in [RFC 5921]. The SP boundaries play the important role to determine the security models for any particular deployment. [Page 6] MPLS-TP Security framework July 2010 This document defines the zone where the single SP has the total operational control to be a trusted zone for that SP. A primary concern is about security aspects that relate to breaches of security from the "outside" of a trusted zone to the "inside" of this zone. 2.1. Security Reference Model 1 In the reference model 1, a single SP has the total control of PE/T-PE to PE/T-PE of the MPLS-TP network. Security reference model 1(a): MPLS-TP network with Single Segment Pseudowire (SS-PW) from PE to PE. The trusted zone is PE1 to PE2 as illustrated in Figure 1. |<-------------- Emulated Service ---------------->| | | | |<------- Pseudo Wire ------>| | | | | | | | |<-- PSN Tunnel -->| | | | V V V V | V AC +----+ +----+ AC V +-----+ | | PE1|==================| PE2| | +-----+ | |----------|............PW1.............|----------| | | CE1 | | | | | | | | CE2 | | |----------|............PW2.............|----------| | +-----+ ^ | | |==================| | | ^ +-----+ ^ | +----+ +----+ | | ^ | | Provider Edge 1 Provider Edge 2 | | | | | | Customer | | Customer Edge 1 | | Edge 2 | | Native service Native service ----Untrusted--- >|<------- Trusted Zone ----- >|<---Untrusted---- Figure 1: MPLS-TP Security Model 1 (a) Security reference model 1(b): MPLS-TP network with Multi-Segment Pseudowire (MS-PW) from T-PE to T-PE. The trusted zone is T-PE1 to T-PE2 in this model as illustrated in Figure 2. [Page 7] MPLS-TP Security framework July 2010 Native |<------------Pseudowire-------------->| Native Service | PSN PSN | Service (AC) | |<--cloud->| |<-cloud-->| | (AC) | V V V V V V | | +----+ +-----+ +----+ | +----+ | |TPE1|===========|SPE1 |==========|TPE2| | +----+ | |------|..... PW.Seg't1.........PW.Seg't3.....|-------| | | CE1| | | | | | | | | |CE2 | | |------|..... PW.Seg't2.........PW.Seg't4.....|-------| | +----+ | | |===========| |==========| | | +----+ ^ +----+ ^ +-----+ ^ +----+ ^ | | | | | TP LSP TP LSP | | | | | |<---------------- Emulated Service ----------------->| -Untrusted >|<----------- Trusted Zone ---------- >|< Untrusted- Figure 2: MPLS-TP Security Model 2 (b) 2.2. Security Reference Model 2 In the reference model 2, a single SP does not have the total control of PE/T-PE to PE/T-PE of the MPLS-TP network, S-PE and T-PE may be owned by different SPs or SPs and their customers. The MPLS- TP network is not contained in one trusted zone. Security Reference Model 2(a) MPLS-TP network with Multi-Segment Pseudowire (MS-PW) from PE to PE. The trusted zone is T-PE1 to S-PE, as illustrated in Figure 3. Native |<------------Pseudowire-------------->| Native Service | PSN PSN | Service (AC) | || |<-cloud-->| | (AC) | V V V V V V | | +----+ +----+ +----+ | +----+ | |TPE1|=========|SPE1|==========|TPE2| | +----+ | |------|.....PW.Seg't1......PW.Seg't3.... .|-------| | | CE1| | | | | | | | | |CE2 | | |------|.....PW.Seg't2......PW.Seg't4..... |-------| | +----+ | | |=========| |==========| | | +----+ ^ +----+ ^ +----+ ^ +----+ ^ | | | | [Page 8] MPLS-TP Security framework July 2010 | TP LSP TP LSP | | | |<---------------- Emulated Service -------------->| --Untrusted-- >|<-- Trusted Zone -->|< ------Untrusted-------- Figure 3: MPLS-TP Security Model 2(a) Security Reference Model 2(b) MPLS-TP network with Multi-Segment Pseudowire (MS-PW) from PE to PE. The trusted zone is S-PE, as illustrated in Figure 3. Native |<------------Pseudowire-------------->| Native Service | PSN PSN | Service (AC) | || |<-cloud-->| | (AC) | V V V V V V | | +----+ +----+ +----+ | +----+ | |TPE1|=========|SPE1|==========|TPE2| | +----+ | |------|.....PW.Seg't1......PW.Seg't3.... .|-------| | | CE1| | | | | | | | | |CE2 | | |------|.....PW.Seg't2......PW.Seg't4..... |-------| | +----+ | | |=========| |==========| | | +----+ ^ +----+ ^ +----+ ^ +----+ ^ | | | | | TP LSP TP LSP | | | |<---------------- Emulated Service -------------->| --------Untrusted----------->|<--->|< ------Untrusted-------- Trusted Zone Figure 4: MPLS-TP Security Model 2(b) Security Reference Model 2(c): MPLS-TP network with Multi-Segment Pseudowire (MS-PW) from different Service Providers with PW inter-provider connections. The trusted zone is T-PE1 to S-PE3, as illustrated in Figure 5. [Page 9] MPLS-TP Security framework July 2010 Native |<-------------------- PW15 --------------------->| Native Layer | | Layer Service | |<-PSN13->| |<-PSN3X->| |<-PSNXZ->| | Service (AC1) V V LSP V V LSP V V LSP V V (AC2) +----+ +-+ +----+ +----+ +-+ +----+ +---+ |TPE1| | | |SPE3| |SPEX| | | |TPEZ| +---+ | | | |=========| |=========| |=========| | | | |CE1|----|........PW1........|...PW3...|........PW5........|---|CE2| | | | |=========| |=========| |=========| | | | +---+ | 1 | |2| | 3 | | X | |Y| | Z | +---+ +----+ +-+ +----+ +----+ +-+ +----+ |<- Subnetwork 123->| |<- Subnetwork XYZ->| Untrusted->|<- Trusted Zone - >| <-------------Untrusted------------ Figure 5: MPLS-TP Security Model 2(c) The boundaries of a trust domain should be carefully defined when analyzing the security properties of each individual network, as illustrated from the above, the security boundaries determined which model would be applied to the use case analysis. A key requirement of MPLS-TP networks is that the security of the trusted zone not be compromised by interconnecting the MPLS-TP, MPLS core infrastructure with another provider's core or T-PE devices, or end users. In addition, neighbors may be trusted or untrusted. Neighbors may be authorized or unauthorized. Even though a neighbor may be authorized for communication, it may not be trusted. For example, when connecting with another provider's S-PE to set up Inter-AS LSPs, the other provider is considered an untrusted but may be authorized neighbor. +---------------+ +----------------+ | | | | | MPLS-TP S-PE1----S-PE3 MPLS-TP | CE1---S-PE1 Network | | Network T-PE2--CE2 | Provider A S-PE2----S-PE4 Provider B | | | | | +---------------+ +----------------+ [Page 10] MPLS-TP Security framework July 2010 For Provider A: Trusted Zone: Provider A MPLS-TP network Trusted neighbors: T-PE1, S-PE1, S-PE2 Authorized but untrusted neighbor: provider B Unauthorized neighbors: CE2 Figure 5. MPLS-TP trusted zone and authorized neighbor. 3. Security Requirements for MPLS-TP This section covers security requirements for securing MPLS-TP network infrastructure. The MPLS-TP network can be operated without control plane or via dynamic control planes protocols. The security requirements related to new MPLS-TP OAM, recovery mechanisms, MPLS- TP and MPLS interconnection, and MPLS-TP specific operational requirements will be addressed in this section. A service provider may choose the implementation options which are best fit for his/her network operation. This document does not state that a MPLS/GMPLS network must fulfill all security requirements listed to be secure. These requirements are focused on: 1) how to protect the MPLS-TP network from various attacks originating outside the trusted zone including those from network users, both accidentally and maliciously; 2) prevention of operational errors resulted from misconfiguration within the trusted zone. 3.1. Protection within the MPLS-TP Network [Page 11] MPLS-TP Security framework July 2010 - MPLS-TP MUST support the physical and logical separation of data plane from the control plane and management plane. That is, if the control plane or/and management plane are attached and cannot function normally, the data plane should continue to forward packets without being impacted. - MPLS-TP MUST support static provisioning of MPLS-TP LSP and PW with or without NMS/OSS, without using control protocols. This is particularly important in the case of security model 2(a) and 2(b) where the some or all T-PEs are not in the trusted zone, and in the inter-provider cases in security model 2(c) when the connecting S-PE is in the untrusted zone. - MPLS-TP MUST support non-IP path options in addition to IP loopback option. Non-IP path option used in the model 2 may help to lower the potential risk of the S-PE/T-PE in the trusted zone to be attacked. - MPLS-TP MUST support authentication of the any control protocol used for MPLS-TP network, as well as MPLS-TP network to dynamic MPLS network inter-connection. - MPLS-TP MUST support mechanisms to prevent DOS attack through in-band OAM G-ACh/GAL. - MPLS-TP MUST support hiding of the Service Provider infrastructure for all reference models regardless using static configuration or dynamic control plane. - Security management requirements [MPLS-TP NM REQ]: o MPLS-TP must support management communication channel security secure communication channels MUST be supported for all network traffic and protocols used to support management functions. This MUST include protocols used for configuration, monitoring, configuration backup, logging, time synchronization, authentication, and routing. The MCC MUST support application protocols that provide confidentiality and data integrity protection. Support the use of open cryptographic algorithms [RFC 3871]; Authentication - allow management connectivity and activity only from authenticated entities, and port access control. o Distributed Denial of Service: It is possible to lessen the impact and potential for DoS and DDoS by using secure protocols, turning off unnecessary processes, logging and [Page 12] MPLS-TP Security framework July 2010 monitoring, and ingress filtering. [RFC 4732] provides background on DOS in the context of the Internet. (more to be added) - Protection of Operational error Due to the extensive use of static provisioning with or without NMS and OSS, the prevention of configuration errors should be addressed as major security requirements. (to be added) 4. Security Threats This section discusses the various network security threats that may endanger MPLS-TP networks. The discussion is limited to those threats that are unique to MPLS-TP networks or that affect MPLS-TP network in unique ways. A successful attack on a particular MPLS-TP network or on a SP's MPLS-TP infrastructure may cause one or more of the following ill effects: 1. Observation, modification, or deletion of a provider's or user's data, as well as replay or insertion of inauthentic data into a provider's or user's data stream, traffic pattern analysis. These types of attacks apply to MPLS-TP traffic in a similar way of MPLS traffic regardless how the LSP is set up. 2. Attacks on GAL label, BFD messages: 1) GAL label or BFD label manipulation: including insertion of false label or messages, or modification, or removal the GAL labels or messages by attackers. 2) DOS attack through in-band OAM G-ACH/GAL, and BFD messages. 3. Disruption of a provider's and/or user's connectivity, or degradation of a provider's service quality. 1) Provider connectivity attacks: - In the case of NMS is used for LSP set-up, the attacks would be through the attack of NMS. [Page 13] MPLS-TP Security framework July 2010 - In the case of dynamic is used for dynamic provisioning, the attack would be on dynamic control plane. Most aspects are addressed in [RFC 5920]. 2) User connectivity attack. This would be similar as PE/CE access attack in typical MPLS networks, addressed in [RFC 5920]. 4. Probing a provider's network to determine its configuration, capacity, or usage. These types of attack can happen through NMS attacks in the case of static provisioning, or through control plane attacks as in dynamic MPLS networks. It can also be combined attacks. It is useful to consider that threats, whether malicious or accidental, may come from different categories of sources. For example they may come from: - Other users whose services are provided by the same MPLS-TP core. - The MPLS-TP SP or persons working for it. - Other persons who obtain physical access to a MPLS-TP SP's site. - Other persons who use social engineering methods to influence the behavior of a SP's personnel. - Users of the MPLS-TP network itself. - Others, e.g., attackers from the other sources, Internet if connected. - Other SPs in the case of MPLS-TP Inter-provider connection. The provider may or may not be using MPLS-TP. - Those who create, deliver, install, and maintain software for network equipment. Given that security is generally a tradeoff between expense and risk, it is also useful to consider the likelihood of different attacks occurring. There is at least a perceived difference in the likelihood of most types of attacks being successfully mounted in different environments, such as: - A MPLS-TP network inter-connecting with another provider's core - A MPLS-TP configuration transiting the public Internet Most types of attacks become easier to mount and hence more likely as the shared infrastructure via which service is provided expands from a single SP to multiple cooperating SPs to the global Internet. Attacks that may not be of sufficient likeliness to warrant concern in a closely controlled environment often merit defensive measures in broader, more open environments. In closed [Page 14] MPLS-TP Security framework July 2010 communities, it is often practical to deal with misbehavior after the fact: an employee can be disciplined, for example. The following sections discuss specific types of exploits that threaten MPLS-TP networks. 4.1. Attacks on the Control Plane - MPLS-TP LSP creation by an unauthorized element - LSP message interception - Attacks on G-Ach - Attacks against LDP - Attacks against RSVP-TE - Attacks against GMPLS - Denial of Service Attacks on the Network Infrastructure - Attacks on the SP's MPLS/GMPLS Equipment via Management Interfaces - Social Engineering Attacks on the SP's Infrastructure - Cross-Connection of Traffic between Users - Attacks against Routing Protocols - Other Attacks on Control Traffic 4.2. Attacks on the Data Plane This category encompasses attacks on the provider's or end user's data. Note that from the MPLS-TP network end user's point of view, some of this might be control plane traffic, e.g. routing protocols running from user site A to user site B via IP or non-IP connections, which may be some type of VPN. - Unauthorized Observation of Data Traffic - Modification of Data Traffic - Insertion of Inauthentic Data Traffic: Spoofing and Replay - Unauthorized Deletion of Data Traffic [Page 15] MPLS-TP Security framework July 2010 - Unauthorized Traffic Pattern Analysis - Denial of Service Attacks - Misconnection 5. Defensive Techniques for MPLS-TP Networks The defensive techniques discussed in this document are intended to describe methods by which some security threats can be addressed. They are not intended as requirements for all MPLS-TP implementations. The MPLS-TP provider should determine the applicability of these techniques to the provider's specific service offerings, and the end user may wish to assess the value of these techniques to the user's service requirements. The operational environment determines the security requirements. Therefore, protocol designers need to provide a full set of security services, which can be used where appropriate. The techniques discussed here include encryption, authentication, filtering, firewalls, access control, isolation, aggregation, and others. 5.1. Authentication To prevent security issues arising from some DoS attacks or from malicious or accidental misconfiguration, it is critical that devices in the MPLS-TP should only accept connections or control messages from valid sources. Authentication refers to methods to ensure that message sources are properly identified by the MPLS-TP devices with which they communicate. This section focuses on identifying the scenarios in which sender authentication is required and recommends authentication mechanisms for these scenarios. 5.1.1. Management System Authentication Management system authentication includes the authentication of a PE to a centrally-managed network management or directory server when directory-based "auto-discovery" is used. It also includes authentication of a CE to the configuration server, when a configuration server system is used. Authentication should be bi-directional, including PE or CE to configuration server authentication for PE or CE to be certain it is communicating with the right server. [Page 16] MPLS-TP Security framework July 2010 5.1.2. Peer-to-Peer Authentication Peer-to-peer authentication includes peer authentication for network control protocols and other peer authentication (i.e., authentication of one IPsec security gateway by another). Authentication should be bi-directional, including S-PE, T-PE, PE or CE to configuration server authentication for PE or CE to be certain it is communicating with the right server. 5.1.3. Cryptographic Techniques for Authenticating Identity Cryptographic techniques offer several mechanisms for authenticating the identity of devices or individuals. These include the use of shared secret keys, one-time keys generated by accessory devices or software, user-ID and password pairs, and a range of public-private key systems. Another approach is to use a hierarchical Certification Authority system to provide digital certificates. 5.2. Access Control Techniques - Access Control to Management Interfaces Most of the security issues related to management interfaces can be addressed through the use of authentication techniques as described in the section on authentication. However, additional security may be provided by controlling access to management interfaces in other ways. The Optical Internetworking Forum has done relevant work on protecting such interfaces with TLS, SSH, Kerberos, IPsec, WSS, etc. See OIF-SMI-01.0 "Security for Management Interfaces to Network Elements" [OIF-SMI-01.0], and "Addendum to the Security for Management Interfaces to Network Elements" [OIF-SMI-02.1]. See also the work in the ISMS WG. Management interfaces, especially console ports on MPLS-TP devices, may be configured so they are only accessible out-of-band, through a system which is physically or logically separated from the rest of the MPLS-TP infrastructure. Where management interfaces are accessible in-band within the MPLS- TP domain, filtering or firewalling techniques can be used to restrict unauthorized in-band traffic from having access to management interfaces. Depending on device capabilities, these [Page 17] MPLS-TP Security framework July 2010 filtering or firewalling techniques can be configured either on other devices through which the traffic might pass, or on the individual MPLS-TP devices themselves. 5.3. Use of Isolated Infrastructure One way to protect the infrastructure used for support of MPLS-TP is to separate the resources for support of MPLS-TP services from the resources used for other purposes 5.4. Use of Aggregated Infrastructure In general, it is not feasible to use a completely separate set of resources for support of each service. In fact, one of the main reasons for MPLS-TP enabled services is to allow sharing of resources between multiple services and multiple users. Thus, even if certain services use a separate network from Internet services, nonetheless there will still be multiple MPLS-TP users sharing the same network resources. In general, the use of aggregated infrastructure allows the service provider to benefit from stochastic multiplexing of multiple bursty flows, and also may in some cases thwart traffic pattern analysis by combining the data from multiple users. However, service providers must minimize security risks introduced from any individual service or individual users. 5.5. Service Provider Quality Control Processes 5.6. Verification of Connectivity In order to protect against deliberate or accidental misconnection, mechanisms can be put in place to verify both end-to-end connectivity and hop-by-hop resources. These mechanisms can trace the routes of LSPs in both the control plane and the data plane. 6. Monitoring, Detection, and Reporting of Security Attacks MPLS-TP network and service may be subject to attacks from a variety of security threats. Many threats are described in Section 3 of this document. Many of the defensive techniques described in this document and elsewhere provide significant levels of protection from a variety of threats. However, in addition to employing defensive techniques silently to protect against attacks, MPLS-TP services can also add value for both providers and [Page 18] MPLS-TP Security framework July 2010 customers by implementing security monitoring systems to detect and report on any security attacks, regardless of whether the attacks are effective. Attackers often begin by probing and analyzing defenses, so systems that can detect and properly report these early stages of attacks can provide significant benefits. Information concerning attack incidents, especially if available quickly, can be useful in defending against further attacks. It can be used to help identify attackers or their specific targets at an early stage. This knowledge about attackers and targets can be used to strengthen defenses against specific attacks or attackers, or to improve the defenses for specific targets on an as-needed basis. Information collected on attacks may also be useful in identifying and developing defenses against novel attack types. 7. Security Considerations Security considerations constitute the sole subject of this memo and hence are discussed throughout. The document describes a variety of defensive techniques that may be used to counter the suspected threats. All of the techniques presented involve mature and widely implemented technologies that are practical to implement. The document evaluates MPLS-TP security requirements from a customer's perspective as well as from a service provider's perspective. These sections re-evaluate the identified threats from the perspectives of the various stakeholders and are meant to assist equipment vendors and service providers, who must ultimately decide what threats to protect against in any given configuration or service offering. 8. IANA Considerations This document contains no new IANA considerations. 9. Normative References [RFC 5654], Niven-Jenkins, B., et al, "MPLS-TP Requirements", RFC 5654, September 2009. [Page 19] MPLS-TP Security framework July 2010 [RFC 3871] Jones, G., "Operational Security Requirements for Large Internet Service Provider (ISP) IP Network Infrastructure", RFC 3871, September 2004. [RFC 4732] Handley, M., et al, "Internet Denial-of-Service Considerations", RFC 4732, November 2006. 10. Informative References [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [OIF-SMI-01.0] Renee Esposito, "Security for Management Interfaces to Network Elements", Optical Internetworking Forum, Sept. 2003. [OIF-SMI-02.1] Renee Esposito, "Addendum to the Security for Management Interfaces to Network Elements", Optical Internetworking Forum, March 2006. [RFC3631] S. Bellovin, C. Kaufman, J. Schiller, "Security Mechanisms for the Internet," December 2003. [MFA MPLS ICI] N. Bitar, "MPLS InterCarrier Interconnect Technical Specification", IP/MPLS Forum 19.0.0, April 2008. [RFC 5921] Bocci, M., Bryant, et al., "A Framework for MPLS in Transport Networks", July 2010. [opsec efforts] C. Lonvick and D. Spak, "Security Best Practices Efforts and Documents", draft-ietf-opsec-efforts-08.txt, June 2008. [RFC 5920] L. Fang, et al, Security Framework for MPLS and GMPLS Networks, July 2010. [MPLS-TP NM REQ] Hing-Kam Lam, Scott Mansfield, Eric Gray, MPLS TP Network Management Requirements, draft-ietf-mpls-tp-nm-req-06.txt, October 2009. 11. Author's Addresses Luyuan Fang Cisco Systems, Inc. 300 Beaver Brook Road Boxborough, MA 01719 USA [Page 20] MPLS-TP Security framework July 2010 Email: lufang@cisco.com Ben Niven-Jenkins Velocix 326 Cambridge Science Park Milton Road, Cambridge CB4 0WG, UK Email: ben@niven-jenkins.co.uk Raymond Zhang British Telecom BT Center 81 Newgate Street London, EC1A 7AJ United Kingdom Email: raymond.zhang@bt.com Nabil Bitar Verizon 40 Sylvan Road Waltham, MA 02145 USA Email: nabil.bitar@verizon.com [Page 21]