I DPID It My Way! A Covert Timing Channel in Software-Defined - - PowerPoint PPT Presentation

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I DPID It My Way! A Covert Timing Channel in Software-Defined - - PowerPoint PPT Presentation

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I DPID It My Way! A Covert Timing Channel in Software-Defined Networks Robert Kro sche, Kashyap Thimmaraju , Liron Schiff and Stefan Schmid IFIP Networking 2018 14-16 May, 2018, Zurich, Switzerland 1 Outline 1. Motivation 2. Covert

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I DPID It My Way! A Covert Timing Channel in Software-Defined Networks

Robert Krösche, Kashyap Thimmaraju, Liron Schiff and Stefan Schmid

IFIP Networking 2018 14-16 May, 2018, Zurich, Switzerland 1

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Outline

1. Motivation 2. Covert Timing Channel 3. CVE-2018-1000155 4. Conclusion

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SLIDE 3

Backdoors and Exploits

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Also Possible With SDN (Virtual) Switches! [SOSR’18]

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Malicious SDN Switches

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SDN Teleportation [EuroSP’17]

A New Attack in Software-Defined Networks

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SDN Teleportation: Violate Network Isolation

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Department

  • f Research

Department

  • f Sales

SDN Controller

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SLIDE 8

SDN Teleportation: Violate Network Isolation

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Department

  • f Research

Department

  • f Sales

SDN Controller

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The Teleportation Model

1) Switch to Controller 2) Controller to Switches 3) Destination Processing

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10 11 10. .. 1) 2) 3)

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Teleportation Techniques

  • Out-of-band Forwarding
  • Flow (Re-)Configuration
  • Switch Identification

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10 11 10. .. 1) 2) 3) Inherent to the OpenFlow specification

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Switch Identification Teleportation

  • OpenFlow Handshake
  • Switches use the same Data Path

Identifier (DPID) to the same controller

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A Covert Timing Channel

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SLIDE 12

Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Features Reply … DPID=1 ... Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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SLIDE 13

Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Features Reply Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 … DPID=1 ...

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Disconnect 10.0.0.2 I could not connect with DPID=1, s1 sent me a “1”.

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SLIDE 15

Covert Timing Channel

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Challenges From One Bit to Multiple Bits

  • Synchronization

○ When to start? ○ How long to wait? ○ Did it start? ○ When to end?

  • Influence of the Controller

○ Load on the controller ○ Controller architecture ○ Path to the controller

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Challenges From One Bit to Multiple Bits

  • Synchronization

○ When to start? ○ How long to wait? ○ Did it start? ○ When to end?

  • Influence of the Controller

○ Load on the controller ○ Controller architecture ○ Path to the controller

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Frame Structure SoF Bit Data Bit ... 1 1 1 1 1 1 1 End of Transmission

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Experimental Evaluation

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Effect of Timing Interval (∆)

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Effect of Frame Length (FL)

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FL 7 SoF Bit Data Bits FL 14 FL 28

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Effect of Timing Interval (∆) and Frame Length (FL)

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/2

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Effect of Timing Interval (∆) and Frame Length (FL)

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/2

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Effect of Timing Interval (∆) and Frame Length (FL)

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/2

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Effect of Timing Interval (∆) and Frame Length (FL)

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/2

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Effect of Delay (δdelay) to Check

  • Conn. Status

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Effect of Delay (δdelay) to Check

  • Conn. Status

No load, M=64bytes, δof f set=5ms and check the conn. status at 2∆/3

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Effect of Load on the Controller

With load (20 switches trigger Packet-Ins following a Poisson distribution with λ=1), M=64bytes, δof f set=5ms and check the conn. status at 2∆/3

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Limitations, Detection and Mitigation

  • Uni-directional and no

error-correction in our prototype

  • System and network limitations, e.g.,

TCP connection establishment time

  • It is difficult to detect Teleportation

attacks as the (OpenFlow) messages are legitimate and within the switch-controller channel

  • We can deter Switch Identification

Teleportation by securing the OpenFlow handshake

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SLIDE 29

CVE-2018-1000155

  • Lack of authentication
  • Lack of authorization
  • Denial of service
  • Difficult to specify the outcome for a switch

ID collision at the controller in OpenFlow

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  • Public disclosure made last week

○ http://www.openwall.com/lists/oss-security /2018/05/09/4 ○ https://www.theregister.co.uk/2018/05/10 /openflow_switch_auth_vulnerability/ ○ https://www.techrepublic.com/article/open flow-sdn-protocol-flaw-affects-all-versions- could-lead-to-dos-attack/

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CVE-2018-1000155: Proposed Mitigation

  • Unique TLS certificates for switches
  • White-list of switch DPIDs at controllers

[Gray et al.] and the respective switches’ public-key certificate identifier

  • A controller mechanism that verifies the

DPID announced in the OpenFlow handshake is over the TLS connection with the associated (DPID) certificate

○ ONOS has already patched, see https://github.com/opennetworkinglab/ono s/commit/f69e3e34092139600404681798 cebeefebcfa6c6 ○ Other controllers to follow

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CVE-2018-1000155: Proposed Mitigation

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Dpid 1 - TLS cert s1 Dpid 2 - TLS cert s2 TLS cert s1 TLS cert s2

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CVE-2018-1000155: Proposed Mitigation

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Dpid 1 - TLS cert s1 Dpid 2 - TLS cert s2 Dpid 1 Features Reply

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SLIDE 33

CVE-2018-1000155: Proposed Mitigation

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Dpid 1 - TLS cert s1 Dpid 2 - TLS cert s2 Features Reply Dpid 1

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SLIDE 34

CVE-2018-1000155: Proposed Mitigation

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Dpid 1 - TLS cert s1 Dpid 2 - TLS cert s2 S2 did not use authorized dpid over authenticated TLS channel!

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Conclusion

  • Introduced a novel covert timing

channel in Software-Defined Networks

  • A fundamental network security

requirement, isolation, can be violated in SDNs using our covert channel

  • Our prototype can achieve

unidirectional throughput of 20bps with ~90% accuracy

  • CVE-2018-1000155 DoS, lack of

authentication and authorization, and covert channel in OpenFlow

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Contact

Kashyap Thimmaraju Email: kash@sect.tu-berlin.de Web: www.fgsect.de/~hashkash Fingerprint: 5FFC 5589 DC38 F6F5 CEF7 79D8 A10E 670F 9520 75CD

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References

1. [SOSR’18] K. Thimmaraju, B. Shastry, T. Fiebig, F. Hetzelt, J.-P. Seifert, A. Feldmann, S. Schmid,” in Proc. ACM Symposium on SDN Research (SOSR), 2018. 2. [EuroSP’17] K. Thimmaraju, L. Schiff, and S. Schmid, “Outsmarting network security with sdn teleportation,” in Proc. IEEE European Security & Privacy (S&P), 2017. 3. [Gray et al.] N. Gray, T. Zinner, and P. Tran-Gia, “Enhancing sdn security by device fingerprinting,” In Proc. IFIP/IEEE International Symposium on Integrated Network Management (IM), May 2017. 4. [Dover] J. M. Dover, “A denial of service attack against the open floodlight sdn controller,” Dover Networks, Tech. Rep., 2013. [Online]. Available: http://dovernetworks.com/wp-content/uploads/ 2013/12/OpenFloodlight-12302013.pdf 5. [Secci et al.] S. ​Secci,​ ​K.​ ​Attou,​ ​D. ​C. ​Phung, S.​ ​Scott-Hayward,​ ​D. ​Smyth,​ S. ​Vemuri​ and ​You​ ​Wang​, “ONOS​ ​Security​ ​and​ ​Performance​ ​Analysis: Report​ ​No.​ ​1” ONOS, 2017. 6. [SNBI] https://wiki.opendaylight.org/view/SNBI_Architecture_and_Design 7. [USE] https://wiki.opendaylight.org/images/2/23/Odl-usc-2014_11_20.pdf

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Backup

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Threats of Switch Id Teleportation

  • Stealing private keys
  • MITM future traffic
  • Fake vpn gateway
  • Send control messages as part of a botnet
  • Surveillance
  • Exfiltration from air-gapped networks with same controller
  • Violate network isolation, fundamental requirement.
  • Physical isolation via disconnected data planes
  • Communication via controller across disconnected data planes
  • Why break isolation is bad?
  • Break in non-obvious way

○ Fundamental security property broken ○ Physically separated

  • Isolation is most basic and required in a network
  • With examples of isolation properties violated

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A More Recent Incident with Cisco

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Software-Defined Networks (SDN)

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Traditional Networks Software-Defined Networks Distributed Control Plane, hard to manage Logically Centralized Control Plane, easy to manage

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Teleportation and OOBF

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Teleportation Poses Several Threats

  • Bypass security mechanisms

○ Circumvent Firewalls and Intrusion Detection Systems

  • Eavesdrop

○ Modify the content of packets in transit

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EuroSP’17 focused on Out-of-band Forwarding

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Teleportation Poses Several Threats

  • Bypass security mechanisms

○ Circumvent Firewalls and Intrusion Detection Systems

  • Eavesdrop

○ Modify the content of packets in transit

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  • Exfiltration

○ Violate physical/logical network isolation ○ Transmit confidential information, e.g., RSA private keys

  • Attack coordination

○ Send/Receive command and control messages from a Bot master

Networking’18 focuses on Switch Identification EuroSP’17 focused on Out-of-band Forwarding

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SLIDE 45

Out-of-band Forwarding

OpenFlow Messages

  • Packet-in
  • Packet-out
  • (Flow-mods)

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Packet-in Packet-out

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SLIDE 46

Message Sequence Pattern

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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TCP Handshake Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Transport Connection Established Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Hello Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Hello Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Features Request Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Tell me your Features, e.g., ID, Ports, etc.

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Features Reply … DPID=1 ... Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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OpenFlow Connection Established Switch from IP 10.0.0.1 has DPID=1 Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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TCP Handshake Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Transport Connection Established

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Hello Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Hello Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Features Request Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Features Reply Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 … DPID=1 ...

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Switch from IP 10.0.0.2 has DPID=1?!

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Disconnect 10.0.0.2 I could not connect with DPID=1, s1 sent me a “1”.

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OpenFlow Handshake

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Switch Identification Teleportation

With ONOS

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OpenFlow Handshake

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State Transition Model

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Receiver Sender

State Transition Model

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Transition Delays

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Transition Delays

1. δs : The time the sender takes to send a binary bit value 2. δr : The time the receiver takes to receive a binary bit value 3. δsc : The time to transition from the Idle state to the OpenFlow-established state 4. δdc : The time to move from the OpenFlow-established state to OpenFlow-disconnected state 5. δof f set: A timeout value the receiver waits before it sets the controller 6. δof -deny : The time to move from OpenFlow-established to OpenFlow-disconnected when the connection is denied 7. δdelay : A timeout value the receiver waits before it checks the OpenFlow connection status 8. δchk -conn : The time the receiver takes to determine a 0 or 1 by checking the OpenFlow connection status 9. δws = ∆ − δs : A timeout value the sender waits before moving from the OpenFlow-established state to OpenFlow-disconnected 10. δwr = ∆ − δr : A timeout value the receiver waits before moving from the OpenFlow-disconnected state to the Idle state

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Boundary Conditions

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Experiments

Measured the accuracy using Levenshtein distance

1. Effect of timing interval (∆) 2. Effect of frame length (FL) 3. Effect of delay in conn. Status (δdelay) 4. Effect of load on the controller 5. Effect of message length (M)

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Timing Diagram

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Effect of Timing Interval (∆) and Frame Length (FL)

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/2

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Effect of Timing Interval (∆) and Frame Length (FL)

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/2

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Effect of Timing Interval (∆) and Frame Length (FL)

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/2

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Timing Diagram

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Timing Diagram

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Done too soon (Delta/3)

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Timing Diagram

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Done later (2Delta/3)

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OOBF Throughput

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Out-of-band Forwarding Throughput

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Accuracy and Error Analysis

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Effect of Delay (δdelay) to Check

  • Conn. Status

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/3

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Effect of Delay (δdelay) to Check

  • Conn. Status

No load, M=64bytes, δof f set=5ms and check the conn. status at ∆/3

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Miss Start Bit Error: noLoad, 2.0d

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Miss Start Bit Error: noLoad, 2/3d

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Miss Start Bit Error: withLoad, 2.0d

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Miss Start Bit Error: withLoad, 2/3d

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End of Message Error: noLoad, 2.0d

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End of Message Error: noLoad, 2/3d

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End of Message Error: withLoad, 2.0d

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End of Message Error: withLoad, 2/3d

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Why TLS is Insufficient

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Switch from IP 10.0.0.2 has DPID=1?!

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Switch from IP 10.0.0.1 had DPID=1 first!

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 Disconnect Switch from IP 10.0.0.2!

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Switch Identification Teleportation

OpenFlow Messages

  • Hello
  • Features Request
  • Features Reply

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Switch s1 10.0.0.1 Switch s2 10.0.0.2 Controller c1 10.0.0.10 I could not connect with DPID=1, s1 sent me a “1”.