Accountable Internet Protocol David Andersen, Hari Balakrishnan, - - PowerPoint PPT Presentation

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Accountable Internet Protocol David Andersen, Hari Balakrishnan, - - PowerPoint PPT Presentation

Aug 04, 2023 440 likes •788 views

Accountable Internet Protocol David Andersen, Hari Balakrishnan, Nick Feamster, Teemu Koponen, Daekyeong Moon, Scott Shenker http://www.aip-arch.net/ Internet Full of Vulnerabilities Distributed DoS Million-Node Botnets Prefix Hijacking IP

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SLIDE 1

Accountable Internet Protocol

David Andersen, Hari Balakrishnan, Nick Feamster, Teemu Koponen, Daekyeong Moon, Scott Shenker

http://www.aip-arch.net/

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SLIDE 2

IP Spoofing Million-Node Botnets

Internet Full of Vulnerabilities

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Distributed DoS Prefix Hijacking Misconfigured Routers DNS Cache Poisoning

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SLIDE 3

3

Ingress Filtering Egress Filtering uRPF

Intrusion Detection

Bro Snort Vuln-based VMM-based Secure Routing S-BGP SoBGP PG-BGP Pushback AITF

Capabilities

SIFF Portcullis TVA Bandwidth- based Traceback Sampled Hash (SPIE) Pi FIT

Filtering Overlays

SOS Mayday Phalanx Honeypots Fast VM forking Honeyd

IP

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SLIDE 4
  • Complicated Mechanisms
  • Many details to circumvent IP weaknesses
  • External Sources of Trust
  • Trusted certificate authorities (e.g., SBGP)
  • Operator Vigilance
  • Semi-manual configuration (e.g., filters,

registries)

Drawbacks (a sampler)

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SLIDE 5

IP Layer Names Don’t Have Secure Bindings

  • Three kinds of IP layer names:

IP address, IP prefix, AS number

  • No secure binding of host to its IP addresses
  • No secure binding of AS number to its IP

prefixes

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SLIDE 6

Accountability

  • Many problems easier to solve

with network-layer accountability: Ability to associate a principal with a message

  • There’s a way to make accountability

intrinsic

6

AIP

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SLIDE 7

How?

  • Key idea: New addressing scheme for

networks and hosts

  • Addresses are self-certifying
  • Simple protocols that use properties of

addressing scheme as foundation

  • Anti-spoofing, secure routing, DDoS

shut-off, etc.

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SLIDE 8

AIP Addressing

Autonomous domains, each with unique ID

AD1 AD2 AD3 Address = AD1:EID

If multihomed, has multiple addresses AD1:EID,AD2:EID,AD3:EID Each host has a global EID [HIP

, DOA, etc.]

Key Idea: AD and EID are self-certifying flat names

  • AD = hash( public_key_of_AD )
  • Self-certification binds name to named entity

Would fail together Single administrative domain An AD...

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SLIDE 9

AIP Forwarding and Routing

Y:EID AD R AD G AD B AD Y Source

Inter-AD routing & forwarding: AD #s only. Intra-AD routing disseminates EIDs. Many routing protocols possible - derive security from AIP self-certification

AD EID

Destination

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SLIDE 10

Roadmap

  • Uses
  • Secure Routing
  • Anti-Spoofing
  • Shut-Off Packets
  • Concerns
  • Scalability
  • Key Management
  • Traffic Engineering

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SLIDE 11

Secure Routing with AIP (for BGP)

  • Origin authentication:

prefix originated by AS X actually belongs to X

  • Path authentication: accuracy of AS path
  • S-BGP requires external infrastructures
  • In past, registries notoriously inaccurate

✓ With AIP: ADs exchange pub keys via BGP messages ✓ Origin auth automatic: ADs are keys! ✓ Path auth: Just like S-BGP , but no PKI Routing R

  • uting Registry

Prefix Pub Key AS PKI AS PKI AS Pub Key

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SLIDE 12
  • Self-certified entity can prove it sent

message:

  • Routers or hosts seeing packet can check the

AD or EID using a challenge-response protocol

Detecting & Preventing Spoofing

P Sent P? {nonce}

A

Yes! { hash(P), nonce } K-1 A

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SLIDE 13

Spoofing vs. Minting

  • AIP guarantee:
  • Nobody but X can claim to be X
  • However:
  • X could invent a new identity

(minting)

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SLIDE 14

Mitigating Minting

  • Peering ADs:
  • Today: List which ASes/Prefixes A can use

(painful for clients and ISPs)

  • AIP: Configure reasonable limit on

number of ADs can announce

  • Edge ADs can limit EIDs similarly

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SLIDE 15

AIP Enables Secure Shut-Off

  • Problem: Compromised zombie sending stream of

unwanted traffic to victim

  • Zombie is “well-intentioned”, owner benign [Shaw]

Shut-off packet { key = Kvictim, TTL, hash=H(P) }

  • Shut-off scheme implemented in NIC

(NIC firmware update requires physical access)

  • Hardware requirements practical
  • Bloom filter for replay prevention (8MB SRAM)

Zombie Victim

P K-1victim

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SLIDE 16

Can AIP Scale?

  • How big will the routing tables be?
  • # of entries: Scale from IP

(ASes vs. prefixes vs. ADs)

  • Diameter: Shrinking in IP

AIP: more ADs on path

  • Size of entries: Larger AIP addresses
  • How much work to process updates?
  • Crypto overhead
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SLIDE 17

BGP Table Size Trends

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50000 100000 150000 200000 250000 300000 1989 1993 1997 2001 2005 Table size (prefixes) Year Prefixes in table Exponential fit

17% annual growth 2020: 1.6M entries

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SLIDE 18

Growth vs. Hardware

  • Semiconductor industry roadmap projects

doubling in ~3 years

  • 50% >> 17%. But let’s look at some #s...
  • In 2020, can we build a cost-effective router

for AIP traffic?

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SLIDE 19

RIB Memory (20 full-table peers, core)

  • By 2020...
  • FIB: Will grow 5-9x
  • DRAM, SRAM, TCAM:

16x growth per $

2007 2011 2020 IP 0.4 ($30) 0.7 ($14) 2.9 ($7) AIP 1.3 ($103) 2.0 ($40) 8.2 ($21) Gigabytes (2007 Dollars) Without counting benefit from AIP flat lookups “IBM claims 22nm SRAM success”

EETimes, Aug 18, 2008

“I/O Data Rates on commodity DRAM devices will increase to

  • ver 8 GB/s by 2022”

ITRS 2007 roadmap

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SLIDE 20

But what about speed?

  • Scariest challenge: Update processing
  • Load ~20 full tables on boot, fast.
  • ... And do S-BGP style crypto verification
  • Limitations: Memory bandwidth, crypto CPU
  • Memory bandwidth: 8.2GB of memory;

today’s memory can handle 1.7GB/sec.

  • Without AIP/S-BGP future router could load in

~30 seconds.

  • With crypto, however...

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SLIDE 21

Crypto overhead still hurts

  • Process update: Validate RSA signature
  • Trivially parallelized
  • Worst-case result - crypto acceleration or

clever BGP tricks reduce time

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2008

(2.8Ghz quad-core)

2020 RSA Validate 35k/sec 480k/sec AIP/S-BGP Table Load ~141 seconds ~66 seconds

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SLIDE 22

Scaling summary

  • Assuming continued network growth and

semiconductor trends... ✓ An AIP router in 2020 will be cheaper than an IP router in 2007 (From RIB/FIB perspective)

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SLIDE 23

Things I haven’t talked about

  • AIP still requires DNS to go from name->AIP
  • Traffic engineering
  • Detecting key compromise
  • Key management (2 level hierarchy)
  • Hierarchical AIP addresses
  • beyond the 2-level flat hierarchy presented here
  • AIP’s benefits to mobility (HIP/TCP Migrate)
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SLIDE 24

Conclusion

  • Q: How to achieve network-layer

accountability in an internetwork?

  • A: Self-certifying internetwork addresses
  • AD:EID (AIP)
  • Each field derived from public keys
  • Accountability intrinsic - has many uses
  • We believe AIP will scale

AIP composes well with mechanisms for mobility, DoS mitigation, availability, etc.

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SLIDE 25

Cryptographic Evolution

  • Each crypto version: 1 combination of

algorithm and parameters

  • To move to new one:
  • Add support in all routers
  • Once reasonably global, start using
  • Begin phase-out of old version
  • We anticipate ~5+ year cycle for this
  • (Must pre-deploy one alternate version)

Crypto Version Public Key Hash (144 bits) Interface (8 bits)

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SLIDE 26

What is an AD?

  • Group of addresses that
  • Are administered together
  • Would fail together under common

failures

  • Examples:
  • A campus, a local organization
  • Non-examples:
  • CMU Pittsburgh / CMU Qatar
  • (Each would be different AD)

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SLIDE 27

Traffic Engineering

  • ADs are good match for inbound TE

techniques - granularity of campus/ customer/reachable subnet

  • If need finer-grained:
  • Note ECMP unchanged;
  • Note DNS load-balancing unchanged;
  • AIP address interface bits to sub-divide AD
  • 8 bits of interface space
  • partition to up to 255 “paths” to a domain
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SLIDE 28

Handling Key Compromise

  • Preventing:
  • Two-level key hierarchy (master signs
  • ffline; routers have temporary key)
  • Detecting:
  • Registry of addresses used
  • e.g., AD registers “EID X is connecting through

me”

  • Registries simple: entirely self-certifying
  • Recovering:
  • Renumber + (self-certifying) revocation

registry

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SLIDE 29

Shut-Off Replay Prevention

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SOP

Sent Before? Receive SOP: Xmit Packet:

key, TTL, hash

P

Hash (SHA-384) Bloom Filter: k=12, size=64 Mbits ...

? ?

Signature OK? Install filter to V

signed, V

Dest Filters Dest Allowed?

?

Sending rate <= 50kpps False Positives < 1 in 35M: Replay 100Mbit/s for > 5 min to trigger (Only if V previously sent SOP to S)

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SLIDE 30

Mutual Shut-Off

  • Attack:
  • Zombie Z wants to flood victim V
  • First, Z pings V. Gets response back.
  • Z sends Shut-Off packet to V.
  • Z floods V.
  • Resolution:
  • Smart-NIC allows V to send SOPs at very

low rate (1 per 30 seconds) even though filtered ➡Hosts can mutually shut-off...

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SLIDE 31

Crypto Version Public Key Hash (144 bits) Interface (8 bits) Vers Normal IP headers ... Random ID # dests

next-dest

# srcs Source EID Source AD Dest EID Dest AD (next hop) Dest AD Stack ... Source AD Stack ...

AIP Address AIP Header

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SLIDE 32

AIP Verification Protocol

Receive pkt w/ src A:E Drop pkt Send nonce to A or E Nonce response must be signed w/ A’s (or E’s) priv key Receive nonce resp Verify signature Add A (or E):iface to accept cache Local AD? N Y N Trust nbr AD? N Y Accept & forward Y In accept cache? SLA, uRPF , …

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SLIDE 33

Protecting Those who Protect Themselves

  • To bound size of accept cache,
  • if too many entries of AD:x, AD:x2, ...
  • Upgrade to “wildcard”: AD:*
  • If many compromised hots in AD, they can

allow others to spoof AD

  • If AD secure, nobody can spoof it
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SLIDE 34

Table Size Projections

  • 17% growth and predictions from Fuller &

Huston; rough agreement for 2020

Year 17% Growth Fuller/Huston 2008 Observed: 247K Observed: 247K 2011 396K 600K-1M 2020 1.6M 1.3-2.3M