bgp security in partial deployment is the juice worth the squeeze?
DESCRIPTION
BGP Security in Partial Deployment Is the Juice Worth the Squeeze?. Robert Lychev Sharon GoldbergMichael Schapira. Georgia Tech Boston University. Boston University. Hebrew University. Partial Landscape of BGP D efenses. What does (partially-deployed) BGPSEC offer over RPKI? - PowerPoint PPT PresentationTRANSCRIPT
1
BGP Security in Partial Deployment
Is the Juice Worth the Squeeze?Robert Lychev Sharon Goldberg Michael
SchapiraGeorgia TechBoston University
Boston University Hebrew University
Partial Landscape of BGP Defenses
2
BGP RPKI (origin authentication)
BGPSEC
S
4323,2828, FB, prefix
S
2828, FB, prefix
S
SP, 4323, 2828, FB, prefix
• In deployment• Crypto done offline
• In standardization• Crypto done online
What does (partially-deployed) BGPSEC offer over RPKI?
(Or, is the juice worth the squeeze?)
Secu
rity
Ben
efits
or J
uice
BGP and BGPSECcoexistence
road to BGPSEC full-deployment is very tricky because introducing security only partially introduces new vulnerabilities not fully deployed BGPSEC provides only meagre benefits over RPKI if network operators do not prioritize security in their routing policies
3
Outline1. 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
BGP
44
Sprint
2828
4323
D69.63.176.0/24
D69.63.176.0/24
2828, D69.63.176.0/24
4323, 2828, D69.63.176.0/24
A
Sprint, 4323, 2828, D69.63.176.0/24
The “1-hop hijack”
55
Sprint
2828
4323
D69.63.176.0/24
Which route to choose?Use routing policies.
e.g. “Prefer short paths”
4323, 2828, D69.63.176.0/24
?A
A, D69.63.176.0/24
Prefix Hijack
66
Sprint
2828
4323
D69.63.176.0/24
Which route to choose?Use routing policies.
e.g. “Prefer short paths”
4323, 2828, D69.63.176.0/24
?A
A69.63.176.0/24
69.63.176.0/24
A, D69.63.176.0/24
A
A69.63.176.0/24
RPKI Prevents Prefix Hijacks
77
Sprint
2828
4323
D69.63.176.0/24RPKI
Binds prefixes to ASes authorized to originate them.
XRPKI invalid!
Sprint checks thatA is not authorized for 69.63.176.0/24
69.63.176.0/24
8
BGP RPKI (origin authentication)
BGPSEC
S
4323,2828, FB, prefix
S
2828, FB, prefix
S
SP, 4323, 2828, FB, prefix
Secu
rity
Ben
efits
or J
uice
prevent prefix hijacks
assume RPKI is fully deployed, and focus on 1-hop hijack.
Partial Landscape of BGP Defenses
prevent route
manipulations
A
S
SP, A, D, prefixA, D, prefixX
BGPSEC invalid!
BGPSEC Prevents the “1-hop hijack”
99
Sprint
2828
4323
D69.63.176.0/24
P/S
P/S
P/S
P/S
S
4323,2828, D, prefix
S
2828, D, prefix
S
SP, 4323, 2828, D, prefix
S
2828, D, prefix
S
4323, 2828, D
, prefix
2828, D, p
refix
S
P/S
?Sprint can verify that
D never sent A, D prefix
S
RPKI
What happens when BGP andBGPSEC coexist?
10
BGP RPKI (origin authentication)
BGPSEC
S
4323,2828, FB, prefix
S
2828, FB, prefix
S
SP, 4323, 2828, FB, prefix
Secu
rity
Ben
efits
or J
uice
prevent prefix hijacks
assume RPKI is fully deployed, and focus on 1-hop hijack.
Partial Landscape of BGP Defenses
prevent route
manipulations
A
What Happens in Partial BGPSEC Deployment?
1111
Sprint
2828
4323
DSiemens
69.63.176.0/24
P/S
P/S
P/S
P/S
Should Sprint choose the long secure path ORthe short insecure one?
P/S
P/S
?Secure ASes must accept legacy
insecure routes
Depends on the interaction between BGPSEC and routing policies!
RPKI
S
4323,2828, D, prefix
S
2828, D, prefix
S
SP, 4323, 2828, D, prefix
A, D69.63.176.0/24
12
BGP Decision Process
1. local preference
(often based on business relationships with neighbors)
2. prefer short routes
…
3. break ties in a consistent manner
13
Security 1st 1. local preference (cost)
(often based on business relationships with neighbors)
Security 2nd 2. prefer short routes (performance)
Security 3rd 3. break ties in a consistent manner
How to Prioritize Security?
Survey of 100 network operators shows that 10%, 20% and 41% would place security 1st, 2nd, and 3rd, [Gill, Schapira, Goldberg’12]
SecurityCost,Performance
Security
Cost,Performance
14
Our Routing Model
Security 1st 1. local preference (cost)
(prefer customer routes over peer over provider routes)
Security 2nd 2. prefer short routes (performance)
Security 3rd 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.]
Our ongoing work tests the robustness of this local pref model.
15
Outline1. Background: BGP, RPKI, BGPSEC, routing policies
2. BGPSEC in partial deployment is tricky1. Protocol downgrade attacks
2. Collateral damages
3. Routing instabilities
3. Is the Juice worth the squeeze?
4. Summary
A
Protocol Downgrade Attack, Security 3rd!
1616
Sprint
2828
4323
D 69.63.176.0/24
P/S
P/S
P/S
S
4323,2828, D, prefix
S
2828, D, prefix
S
SP, 4323, 2828, D, prefix
P/S
Security 3rd: 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, D69.63.176.0/24
17
Partial Deployment is Very Tricky!
We prove… No protocol downgrades?
No collateral damages?
No instabilities?
Security 1st
Security 2nd
Security 3rd
A2828
4323
D
Siemens
69.63.176.0/24
P/S
P/S
P/S
A, D69.63.176.0/24
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
Collateral Damages; Security 2nd
325720960
56173356
5214212389
Mprefix
10310
404267922
174
3491
P/S
P/S
P/S
P/S
P/S
Collateral Damages; Security 2nd
W
XZ
Y
M
Before X deploys BGPSEC
?X offers the shorter path
?Shorter path!
prefix D
V
P/S
P/S
P/S
P/S
P/S
Secure ASes: 5Happy ASes: 8
Collateral Damages; Security 2nd
W
X VZ
Y
M
?W offers the shorter path!
?Security 2nd:Security trumps
path length!
Y experiences collateral damage because X is secure!
P/S
P/S
P/S
P/S
P/S
Secure ASes: 6Happy ASes: 7
After X deploys BGPSEC
prefix D
P/S
21
Partial Deployment is Very Tricky!
We prove… No protocol downgrades?
No collateral damages?
No instabilities?
Security 1st Security 2nd Security 3rd
325720960
56173356
5214212389
A
?
?
5617
Collateral damage (during the attack): More secure ASes leads to more insecure ASes choosing bogus routes
10310
404267922
174
3491
prefix
P/S
P/S
P/S
P/S
P/S
P/S
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We prove… No protocol downgrades?
No collateral damages?
No instabilities?
Security 1st Security 2nd Security 3rd
Partial Deployment is Very Tricky!
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.
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Outline1. 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
Let S be the set of ASes deploying BGPSEC, A be the attacker and d be the destination
The set of ASes choosing a legitimate route is
Happy S , ,
prefix
Quantifying Security: A Metric
325720960
56173356
5214212389
?
10310
d7922
5617 174
3491
A d prefix
A
| Happy(S, A, d)| = 7
∑
all Aall 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 , ,
Quantifying Security: A Metric
| Happy(S, A, d)| = 7
|V| 31
Metric(S) =
prefix
325720960
56173356
5214212389
?
10310
d7922
5617 174
3491
A
A d prefix
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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 , ,
It is Hard to Decide Whom to Secure
A d prefix
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∑
all Aall d
Problem: Compute upper and lower bounds on
for any BGPSEC deployment set S
Bound Security Benefits for any S!
Happy S , , |V| 31
Metric(S) = A d prefix
A
Bounding Security Metric. Security 3rd
2828
Sprint
2828
4323
DSiemens
69.63.176.0/24
A, D69.63.176.0/24
The bogus path is shorter!
A
Bounding Security Metric. Security 3rd
2929
Sprint
2828
4323
DSiemens
P/S
Sprint is doomed The bogus path is shorter!
P/S
P/S
P/S
P/S
Regardless of who is secure, Sprintwill select the shorter bogus route!
69.63.176.0/24
A, D69.63.176.0/24
A
Bounding Security Metric. Security 3rd
3030
Sprint
2828
4323
DSiemens
P/S
P/S
P/S
P/S
P/S
69.63.176.0/24
A, D69.63.176.0/24
The legitimate path is shorter!
Sprint is doomed The bogus path is shorter!
A
Bounding Security Metric. Security 3rd
3131
Sprint
2828
4323
DSiemens
69.63.176.0/24
2828 and 4323are immune
The legitimate path is shorter!
A, D69.63.176.0/24
Regardless of who is secure, 4323 and 2828 will select legitimate routes!
Sprint is doomed The bogus path is shorter!
32
∑
all Aall d
Problem: Find upper and lower bound on
Different Idea: Bound Security Benefits!
Key observation. Regardless of who is secure:1. Doomed ASes will always choose bogus routes2. 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| 31
Metric(S) = A d prefix
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Security Benefits Bounds over RPKI
lower boundwith RPKI
17%
upper boundwith BGPSEC
In the most realistic security 3rd model, the best we could do is make extra 17% happy with security!
53%
36%47%
Ave
rage
Fra
ctio
n of
Hap
py A
Ses
results based on simulations on empirical AS-level graphs
34
lower boundwith RPKI
17%53%
36%47%
Securing 113 High Degree ASes & their Stubs
Securing 50% of ASes on the Internet
Improvements in the security 3rd and 2nd models are only 4% and 8% respectively.
24%
Ave
rage
Fra
ctio
n of
Hap
py A
Ses
results based on simulations on empirical AS-level graphs
35
Graph: A UCLA AS-level topology from 09-24-2012 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 09-24-2012
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
Our Methodology
36
BGP RPKI (origin authentication)
BGPSEC
S
4323,2828, FB, prefix
S
2828, FB, prefix
S
SP, 4323, 2828, FB, prefix
Secu
rity
Ben
efits
or J
uice
prevent prefix
hijack
Unless Security is 1st or BGPSEC deployment is very large, security benefits from partially deployed BGPSEC are meagre
Typically little observable difference between Sec 2nd and 3rd
So Is the Juice Worth the Squeeze?
prevent route
manipulations
BGP and BGPSECcoexistence: very tricky
*protocol downgradescollateral damagesrouting instabilities
37
THANK YOU
check out the full version at http://arxiv.org/abs/1307.2690
1 Proofs2 More empirical analysis and plots3 Robustness tests4 BGPSEC deployment guidelines