1 Robert Lychev Sharon GoldbergMichael Schapira Georgia Tech Boston University Hebrew University

YouTube Pakistan Telecom Pakistan Telecom Telnor Pakistan Telnor Pakistan Aga Khan University Aga Khan University Multinet Pakistan Multinet Pakistan The Internet I’m YouTube: IP /22 I’m YouTube: IP /22

What should have happened… YouTube Pakistan Telecom Pakistan Telecom Telnor Pakistan Telnor Pakistan Aga Khan University Aga Khan University Multinet Pakistan Multinet Pakistan I’m YouTube: IP /22 I’m YouTube: IP /22 X drop packets

YouTube Pakistan Telecom Pakistan Telecom Telnor Pakistan Telnor Pakistan Aga Khan University Aga Khan University Multinet Pakistan Multinet Pakistan I’m YouTube: IP /22 I’m YouTube: IP /22 Pakistan Telecom Pakistan Telecom No, I’m YouTube! IP /24 No, I’m YouTube! IP /24 What did happen

5

Rare Occurances? Not Really!

7 1. Background: 1. BGP, RPKI, BGPSEC 2. routing policies in BGPSEC partial deployment 2. BGPSEC in partial deployment is tricky 3. Is the juice worth the squeeze? 4. Summary

Microsoft Verizon Comcast AT&T Over 45,000 Autonomous Systems (ASes)

99 Sprint D /24 D /24 D / , D / , D / , 2828, D / , 2828, D /24 A Sprint, 4323, 2828, D /24 Sprint, 4323, 2828, D /24

10 Sprint D /24 Which route to choose? Use routing policies. e.g. “Prefer short paths” 4323, 2828, D / , 2828, D /24 ? A A, D /24 A, D /24

11 Sprint D /24 Which route to choose? Use routing policies. e.g. “Prefer short paths” 4323, 2828, D / , 2828, D /24 ? A A /24 A /24 A, D /24 A, D /24

A A /24 A /24 12 Sprint D /24 RPKI Binds prefixes to ASes authorized to originate them. X RPKI invalid! Sprint checks that A is not authorized for / /24

13 BGP RPKI ( origin authentication ) BGPSEC S S 4323,2828, FB, prefix S S 2828, FB, prefix S S SP, 4323, 2828, FB, prefix Security Benefits or Juice prevent prefix hijacks assume RPKI is fully deployed, and focus on 1-hop hijack. prevent route manipulations

A S S SP, A, D, prefix A, D, prefix X BGPSEC invalid! 14 Sprint D /24 P/S S S 4323,2828, D, prefix S S 2828, D, prefix S S SP, 4323, 2828, D, prefix S S 2828, D, prefix S S 4323, 2828, D, prefix 2828, D, prefix S S P/S ? Sprint can verify that D never sent A, D prefix S S RPKI

What happens when BGP and BGPSEC coexist? 15 BGP RPKI ( origin authentication ) BGPSEC S S 4323,2828, FB, prefix S S 2828, FB, prefix S S SP, 4323, 2828, FB, prefix Security Benefits or Juice prevent prefix hijacks assume RPKI is fully deployed, and focus on 1-hop hijack. prevent route manipulations

A 16 Sprint D Siemens /24 P/S Should Sprint choose the long secure path OR the short insecure one? P/S ? Secure ASes must accept legacy insecure routes Depends on the interaction between BGPSEC and routing policies! RPKI S S 4323,2828, D, prefix S S 2828, D, prefix S S SP, 4323, 2828, D, prefix A, D /24 A, D /24

17 1. local preference (often based on business relationships with neighbors) 2.prefer short routes … 3.break ties in a consistent manner

Security 1 st 1. local preference (cost) (often based on business relationships with neighbors) Security 2 nd 2.prefer short routes (performance) Security 3 rd 3.break ties in a consistent manner 18  Survey of 100 network operators shows that 10%, 20% and 41% would place security 1 st, 2 nd, and 3 rd, [Gill, Schapira, Goldberg’12] Security Cost,Performance SecurityCost,Performance

19 Security 1 st 1. local preference (cost) (prefer customer routes over peer over provider routes) Security 2 nd 2.prefer short routes (performance) Security 3 rd 3.break ties in a consistent manner  To simulate routing outcomes, we use a concrete model of local preference. [Gao-Rexford’00, Huston’99, etc.]  We test the robustness of this local pref model.

20 1. Background: BGP, RPKI, BGPSEC, routing policies 2. BGPSEC in partial deployment is tricky 1. Protocol downgrade attacks 2. Collateral damages 3. Routing instabilities 3. Is the Juice worth the squeeze? 4. Summary

A 21 Sprint D /24 P/S S S 4323,2828, D, prefix S S 2828, D, prefix S S SP, 4323, 2828, D, prefix P/S Security 3 rd : Path length trumps path security! ? Protocol downgrade attack: Before the attack, Sprint has a legitimate secure route. During the attack, Sprint downgrades to an insecure bogus route. A, D /24 A, D /24

22 A D Siemens /24 P/S A, D /2 4 A, D /2 4 P/S ? Protocol downgrade attack: A secure AS with a secure route before the attack, downgrades to an insecure bogus route during the attack. Sprint P/S

M prefix P/S

W XZ Y M Before X deploys BGPSEC ? X offers the shorter path ? Shorter path! prefix D V P/S Secure ASes: 5 Happy ASes: 8

W XVZ Y M ? W offers the shorter path! ? Security 2 nd : Security trumps path length! Y experiences collateral damage because X is secure! P/S Secure ASes: 6 Happy ASes: 7 After X deploys BGPSEC prefix D P/S

A ? ? 5617 Collateral damage (during the attack): More secure ASes leads to more insecure ASes choosing bogus routes prefix P/S

27 Theorem: Routing converges to a unique stable state if all ASes use the same secure routing policy model.  But, if they don’t, there can be BGP Wedgies and oscillations.

28 1. Background: BGP, RPKI, BGPSEC, routing policies 2. BGPSEC in partial deployment is tricky 3. Is the Juice worth the Squeeze? 1. Can we efficiently select the optimal set of secure ASes? 2. Can we bound security benefits invariant to who is secure? 3. Is the BGPSEC juice worth the squeeze given RPKI? 4. Summary

∑ all A all d Let S be the set of ASes deploying BGPSEC, A be the attacker and d be the destination Our metric is the average of the set of Happy ASes Happy S,, 29 | Happy(S, A, d) | = 7 |V| 3 1 Metric(S) = prefix ? d A A d prefix

Problem: find set S of secure ASes that maximizes s. t. |S| = k, for a fixed attacker A and destination d Theorem: This problem is NP-hard for all three routing models. Happy S,, 30 A d prefix

A 31 Sprint D Siemens /24 A, D /24 A, D /24 The bogus path is shorter!

A 32 Sprint D Siemens P/S Sprint is doomed The bogus path is shorter! P/S Regardless of who is secure, Sprint will select the shorter bogus route! /24 A, D /24 A, D /24

A 33 Sprint D Siemens P/S /24 A, D /24 A, D /24 The legitimate path is shorter! Sprint is doomed The bogus path is shorter!

A 34 Sprint D Siemens / and 4323 are immune The legitimate path is shorter! A, D /24 A, D /24 Regardless of who is secure, 4323 and 2828 will select legitimate routes! Sprint is doomed The bogus path is shorter!

∑ all A all d Problem: Find upper and lower bound on 35  Key observation. Regardless of who is secure: 1.Doomed ASes will always choose bogus routes 2.Immune ASes will always choose legitimate routes  Lower bound on Metric(S) = fraction of immune ASes  Upper bound on Metric(S) = 1 – fraction of doomed ASes Happy S,, |V| 3 1 Metric(S) = A d prefix

36 lower bound with RPKI 17% upper bound with BGPSEC In the most realistic security 3 rd model, the best we could do is make extra 17% happy with security! 53% 36% 47% Average Fraction of Happy ASes results based on simulations on empirical AS-level graphs

37 lower bound with RPKI 17% 53% 36% 47% Securing 50% of ASes on the Internet Improvements in the security 3 rd and 2 nd models are only 4% and 8% respectively. 24% Average Fraction of Happy ASes results based on simulations on empirical AS-level graphs

38 BGP RPKI ( origin authentication ) BGPSEC S S 4323,2828, FB, prefix S S 2828, FB, prefix S S SP, 4323, 2828, FB, prefix Security Benefits or Juice prevent prefix hijack  Unless Security is 1 st or BGPSEC deployment is very large, security benefits from partially deployed BGPSEC are meagre  Typically little observable difference between Sec 2 nd and 3 rd prevent route manipulations BGP and BGPSEC coexistence: very tricky *protocol downgrades collateral damages routing instabilities

1. A grassroots approach to routing security  anonymity service in lieu of a PKI 2. Outsourcing interdomain routing to a non- trusted center  via Secure MultiParty Computation (SMPC)

40 check out the full version at 1Proofs 2More empirical analysis and plots 3Robustness tests 4BGPSEC deployment guidelines

41  Graph: A UCLA AS-level topology from  39K ASes, 73.5K and 62K customer-provider and peer links  For each attacker-destination pair, simulated routing and determined the sets of doomed and immune ASes  Quantified security-benefit improvements for many different BGPSEC deployment scenarios  Robustness Tests  added 550K extra peering links inferred from IXP data on  accounted for traffic patterns by focusing on only certain destinations (e.g. content providers) and attackers  currently repeating all analysis with respect to different local pref models

A 42 Sprint D Siemens / and 4323 are immune The legitimate path is shorter! Sprint is doomed The bogus path is shorter! Only Siemans is neither doomed nor immune! A, D /24 A, D /24

A 43 Sprint D Siemens P/S 2828 and 4323 are immune The legitimate path is shorter! Sprint is doomed The bogus path is shorter! P/S Regardless of who is secure, only Siemans can benefits from BGPSEC! Only Siemans is neither doomed nor immune! /24 A, D /24 A, D /24

44 lower bound with RPKI 53% 17% 79% upper bound with BGPSEC In the most realistic security 3 rd model, the best we could do is make extra 17% happy with security! 10% 30% 11% upper bound with BGPSEC

45 lower bound with RPKI 53% Improvements in the security 3 rd and 2 nd models are only 4% and 8% respectively. 10% 30% 11% 17% 79% Securing 50% of the Internet 24%

46  we highlight operational issues of BGPSEC partial deployment  results are not meant to be predictive, but our trends are robust

47  Network administrators have to agree on security prioritization  otherwise, unpredictable routing behavior may be encountered  ASes deploying BGPSEC experience noticeable security benefit improvements when routing to secure destinations  secure islands could form with different security prioritizations  Overall security benefits are almost the same even when STUBs deploying BGPSEC do not verify routes themselves  Tier 1 networks are not a good choice for initial deployment  protocol downgrades  most ASes are immune (i.e. happy to begin with)

48 lower bound with RPKI 60% 15% 77% upper bound with BGPSEC In the most realistic security 3 rd model, the best we could do is make extra 15% happy with security! 12% 25% 11%

49 lower bound with RPKI 62% 16% 80% upper bound with BGPSEC 10% 22% 10% IXP-links augmented graph average over all attackers

50 lower bound with RPKI 54% 19% 82% upper bound with BGPSEC 8% 27% 10% IXP-links augmented graph average over only non-stub attackers

51 lower bound with RPKI 72% 11% 51% upper bound with BGPSEC 41% 17% 8% average over all attackers Local Pref: prefer customer over peer over provider routes, but prefer 1-hop and 2-hop peer routes to customer routes longer than 1 and 2 hops respectively

52 lower bound with RPKI 63% 15% 55% upper bound with BGPSEC 35% 22% 10% average over only non-stub attackers Local Pref: prefer customer over peer over provider routes, but prefer 1-hop and 2-hop peer routes to customer routes longer than 1 and 2 hops respectively

53 lower bound with RPKI 75% 13% 39% upper bound with BGPSEC 55% 12% 6% IXP-links augmented graph average over all attackers Local Pref: prefer customer over peer over provider routes, but prefer 1-hop and 2-hop peer routes to customer routes longer than 1 and 2 hops respectively

54 lower bound with RPKI 64% 16% 44% upper bound with BGPSEC 47% 20% 9% IXP-links augmented graph average over only non-stub attackers Local Pref: prefer customer over peer over provider routes, but prefer 1-hop and 2-hop peer routes to customer routes longer than 1 and 2 hops respectively

55 Sec 3 rd model

56 Sec 2 nd model

57 Sec 3 rd model IXP-links augmented graph

58 Sec 2 nd model IXP-links augmented graph

59 pessimistic: consider all neutral ASes as unhappy optimistic: consider all neutral ASes as happy 0 20K ASes deploying S*BGP Improvement in Happy(S) Securing 50% of the Internet

60 pessimistic: consider all neutral ASes as unhappy optimistic: consider all neutral ASes as happy 0 20K ASes deploying S*BGP Improvement in Happy S (S) Securing 50% of the Internet

61 downgrades and collateral benefits play a significant role in the security metric improvement Sec 3rd Sec 1st

62 cost is more important than security security is more important than cost (AS 4, AS 5, AS 1 ) … AS 5 (AS 3, AS 2, AS 1 ) … AS 4 P/S AS 2 P/S AS 3 P/S AS 1 P/S AS1, /24 S S (AS 1 ) … (AS 1 ) … $ $ $ $ $

63 cost is more important than security security is more important than cost (AS 4, AS 5, AS 1 ) … AS 5 (AS 3, AS 2, AS 1 ) … AS 4 P/S AS 2 P/S AS 3 P/S AS 1 P/S AS1, /24 S S (AS 1 ) … (AS 1 ) … P/S