Fairness Attacks in the eXplicit Control Protocol - PowerPoint PPT Presentation

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Fairness Attacks in the eXplicit Control Protocol

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'Honesty is for the most part less profitable than dishonesty' ... Detectable anywhere in network path. Motivation for attack is lacking. Can not be used to DoS ... – PowerPoint PPT presentation

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Title: Fairness Attacks in the eXplicit Control Protocol


1
Fairness Attacks in the eXplicit Control Protocol
  • Christo Wilson
  • Christopher Coakley
  • Ben Y. Zhao
  • University of California Santa Barbara

2
Motivation
  • Heavy research in recent years into explicit
    feedback protocols
  • Demonstrate desirable qualities
  • Fairness between flows
  • High utilization
  • Few drops
  • No slow start
  • Not security aware
  • Honesty is for the most part less profitable
    than dishonesty -- Plato, The Republic
  • Our work quantifying the impact of attackers
    through detailed experiments

3
Table of Contents
  • Background and Attack Model
  • Experimental Setup
  • Sender-side Attacker
  • Congestion controlled
  • Fully Unresponsive
  • Receiver-side Attacker
  • Proposed Defenses
  • Conclusion

4
Background Explicit Feedback
Bottleneck
Explicit Feedback Enabled Internet
5
Attack Model
  • Feedback mechanism abuse enables attacks
  • Selective compliance with feedback
  • Falsified feedback
  • Two attack types
  • Sender-side ignores feedback
  • Receiver-side falsifies header information
  • Attacker goals
  • Control as much bandwidth as possible
  • Denial of Service (DoS) remote hosts

6
Experimental Setup
  • Attacker models implemented using XCP
  • Tests performed in ns2
  • 10ms latency
  • 1KB packets
  • Drop-tail queues
  • 20 Mbit bottleneck link

7
Sender-side Attacker
Explicit Feedback Enabled Internet
8
Sender-side Attacker
  • Two types of attackers implemented
  • Congestion controlled
  • TCP like behavior
  • Continuous additive c_wnd growth
  • Multiplicative c_wnd back off after packet drop
  • Fully unresponsive
  • Only probes for bandwidth once (1 packet drop)
  • Locks c_wnd at 50 of current size
  • Trumps congestion controlled attackers
  • Resumes probing in response to
  • positive feedback
  • 25 reduction in RTT

9
Sender-side Attacker (Congestion Controlled)
  • 9 Sender-Side Attackers w/ 1 Normal Flow

10
Sender-side Attacker
  • Two types of attackers implemented
  • Congestion controlled
  • TCP like behavior
  • Continuous additive c_wnd growth
  • Multiplicative c_wnd back off after packet drop
  • Fully unresponsive
  • Only probes for bandwidth once (1 packet drop)
  • Locks c_wnd at 50 of current size
  • Trumps congestion controlled attackers
  • Resumes probing in response to
  • positive feedback
  • 25 reduction in RTT

11
Sender-side Attacker (Fully Unresponsive)
  • 1 Sender-Side Attacker w/ 49 Normal Flows

12
Sender-side Attacker (Fully Unresponsive)
  • 4 Sender-Side Attackers w/ 1 Normal Flow

13
Receiver-side Attacker
Explicit Feedback Enabled Internet
14
Receiver-side Attacker
  • 1 Receiver-Side Attacker w/ 49 Normal Flows

15
Proposed Defenses Edge Monitors
  • Edge monitors
  • Must be ubiquitous
  • Requires per flow monitoring/state
  • Sender-side attacks detected by monitoring actual
    versus expected throughput
  • Receiver-side attacks are trivially detected
  • Issues
  • Ubiquity of monitors can not be guaranteed
  • Unfeasible router overhead
  • Network edge does not exist

16
Proposed Defenses Attack Severity
  • Sender-side attacks are tractable problem
  • Elephant flow monitors exist
  • Detectable anywhere in network path
  • Motivation for attack is lacking
  • Can not be used to DoS
  • Receiver-side attacks represent difficult
    challenge
  • Can target/break well behaved hosts
  • DoS potential
  • Motivation for attack is much stronger

17
Proposed Defenses Nonce Feedback Injection
Explicit Feedback Enabled Internet
18
Proposed Defenses Nonce Feedback Injection
Explicit Feedback Enabled Internet
19
Conclusion
  • Existing explicit feedback protocols are
    vulnerable to exploitation
  • Sender-side attacks
  • Receiver-side attacks
  • Attacks are highly effective
  • Applies to existing explicit feedback protocols
  • XCP, RCP, MaxNet, JetMax, etc
  • Proposed solutions are inadequate
  • Potential solution nonce feedback injection

20
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