Mpls hacking security Myth
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This document discusses potential security issues related to MPLS networks. It begins by defining some MPLS terminology like Label Distribution Protocol, Label Switched Path, and Label Switching Router. It then explores ideas like an attacker rewriting MPLS labels to redirect traffic or injecting spoofed messages into the Label Distribution Protocol to manipulate label mappings. However, the document notes that actually exploiting these issues against a real telecom backbone would be very difficult or impossible due to network controls and monitoring. The goal is to raise awareness of security considerations for MPLS rather than enable real attacks.
Mpls hacking security Myth
- 1. MPLS : Hacking & Security Myth of The Beast In Core Telecommunication Network gcsf@nowhere
- 2. WHY? TELCO Technology? Industry, Community, Academic? Ask Others to also share their high quality research Taking Indonesian Hacking Scene to The Higher Level (?)
- 3. MPLS? MPLS is routing mechanism in high-performance network backbone Route the data traffic from a node to the next node based on short path labels Avoiding complex forwarding mechanism in routing table Operate in between layer 2 and layer 3 (OSI model), taking advantage on the layer 2 switching performance and layer 3 routing scalability MPLS Architecture is very well written on RFC 3031
- 4. MPLS Terminology? Label Distribution Protocol (LDP) Label Switched Path (LSP) Label Switching Router (LSR) Label Edge Router (LER) / MPLS Edge Node Virtual Routing & Forwarding (VRF) CE/PE/P Router MORE? (We only describe terminology used in this document)
- 6. MPLS Usage Virtual Private Routed Network (VPRN) – L3VPN Virtual Private LAN Service (VPLS) – L2VPN Virtual Leased Line (VLL) Traffic Engineering In order to limit this presentation, we will only discuss L3VPN
- 7. MPLS In Broadband Network
- 8. Myth - MPLS Hacking & Security? Provider Edge (PE) router Encryption support Traffic Sniffing MPLS Label Label Distribution Protocol Border Gateway Protocol REFERENCE : ERNW.DE
- 9. PE Router • Usually to be shared among customers • Multiple CE router from multiple customers is connected to the single PE router • Still, the security relies on the trust model of provider private network • Missing configuration of PE router? (E.G: Mgmt Access) • A customer sending crafted packet to PE to deny services
- 10. Encryption Support MPLS doesn’t provide encryption mechanism Encryption of traffic in core telco relies on the encryption mechanism of higher OSI level The security relies on the trust model of provider private network There are some appliance that can be used to help the traffic encryption (Eg: SafeNet, Senetas) IPSEC over MPLS?
- 11. Traffic Sniffing? P/PE Router? Remember, by default no encryption support! Cisco Embeded Packet Capture (EPC) Cisco “debug packet” with hiden option “dump” Juniper “set forwarding-options packet-capture” Port Mirroring is commonly used Appliance is also commonly used (E.g: VSS, NetOptics) DPI? LI?
- 13. MPLS Label • Injection of labeled traffic from customer CE router – RFC 2547, labeled traffic from non trusted sources must be discarded • Injection of labeled traffic from Internet – Again RFC 2547, labeled traffic from non trusted sources must be discarded • MPLS label rewriting in MPLS backbone – Possible, can be reproduced in the Lab, hard (impossible?) to implement in the real backbone
- 14. MPLS Label Rewrite MPLS, as previously stated, use label to forward traffic VRF “Black” & “Blue” in PE, store routing table virtually separated, hence overlap network between Bank “Black” & Bank “Blue” can be forwarded correctly Bank “Black” can only communicate with Bank “Black” using VRF Black Bank “Blue” can only communicate with Bank “Blue” using VRF Black
- 15. MPLS Label Rewrite Someone in “Man In The Middle” position between PE1 & PE2 can rewrite the MPLS Label Whoever they are, they can redirect traffic so Bank “Black” can communicate with Bank “Blue” Bank “Black” has overlap network with Bank “Blue” Hence, VRF “Black” and “Blue” has same routing entry Attacker change label for traffic PE1 to PE2 with 21 & PE2 to PE1 with 15 (see table) PE2 only know that traffic from PE1 with label 21 is for Bank “Blue” PE1 only know that traffic from PE2 with label 15 is for Bank “Black” Bank “Black” can communicate with Bank “Blue” Reproduce in lab, hard (impossible?) in real MPLS network
- 16. Label Distribution Protocol • Protocol used by MPLS routers to exchange label mapping information • UDP 646 for Hello, TCP 646 for establishing LDP Session • Two MPLS routers that established LDP session called LDP Peers • Exchange of information (advertisement) is bi-directional between LDP Peers • Very well documented on RFC 5036 LDP Session Establishment (SRC: Wikipedia) Discovery Message Session Message Advertisement Message Notification Message
- 17. LDP Message Injection • LDP is used to maintain LSP databases that are used to forward traffic through MPLS Network • How if someone can inject label mapping message to LSR? • Attacker needs access to the MPLS backbone so he can: 1. Announce & maintain the presence of LSR (Hello/Discovery Message) 2. Establish & maintain LDP session (Session Message) 3. Send advertisement with label mapping message & change label database to redirect the traffic • Again, hard (impossible?) in real MPLS network but can be reproduced in lab with specific conditions/requirements
- 18. Border Gateway Protocol • MP-BGP, in MPLS network, usually runs between PE router • It is used to route network which their routing table is in VRF • Attacker needs access to MPLS backbone either for: – Intercept & tamper initial MP-BGP exchange OR – Withdraw routes & insert new one (BGP Update with spoofed NLRI) • Again, hard (impossible?) in real MPLS network but can be reproduced in lab with specific conditions/requirements
- 19. AN EXAMPLE PROVIDED BY LOKI PROJECT/ERNW.DE MPLS (We Only Use This For The Document) ◦ LDP, MPLS Label Rewrite ROUTING ◦ RIP, OSPF, EIGRP, BGP HOT-STANDBY ◦ HSRP, HSRPv2, BFD, VRRP, VRRPv3 ARP Spoofing, MAC Flooding ICMPv6 DOT1Q TCP-MD5
- 20. DEMO
- 21. DEMO TOPOLOGY
- 22. DISCUSSION?! Q & A
- 23. THANK YOU