Resilient SDN Controllers
Arun Sood, PhD
Prof Computer Science, Dir International Cyber Center, GMU
Founder CEO SCIT Labs
Shahid N. Shah
CEO Netspective Communications
All Rights Reserved - SCIT Labs Confidential
and Proprietary
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Application Application
Application Application
Controller
Management
Monitoring
APIs
SDN
Devices
Application
Layer
Control
Layer
Infrastructure
Layer
SDN Architecture
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SDN Controllers
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• Centralized or Distributed
• Potential for single point of failure
• Physical access
• Static systems
• Monitoring and remote access
• Software driven - vulnerable to attack
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Breaches in the News
• South Carolina Department of Revenue: 33 malwares were
used to attack 44 systems
– 75 GB lost; 3.8 M individual and >699K business tax
returns; remediation cost estimated at $19 million
• Target: False positives overwhelmed the security team
– 40 million credit debit card info stolen; $236 million in
expenses
• Home Depot: Zero day attack – customized malware was not
detected
– 56 M cards stolen over five months. Cost $62 million
• Reactive Security works some of the time. Remediation
costs are high
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Cyber Threat Observations
I. Intrusions are inevitable. Most breaches
discovered by third parties
II. Malware installed. Intruders stay in systems for
days, weeks, months
III. Current servers are “sitting ducks”
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IDS,
Firewall,
IPS
Monitoring
High Losses Low
High Intruder Residence Low
Manual
Reimage
Resilience
Automated
Restoration
Losses vs Intruder Residence
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Perfect
Software
White Listing
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Cyber Resilience
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• Typical requirements
– Continuity of operations
– Meet mission requirements
– Limited degradation of performance
• Operational requirement for threat deterrence
– Restoration to pristine uncontaminated state
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Risk Management Approach
Cyber Risk = Threats x Vulnerabilities x Consequences
Focus on Consequence Management
Resilience through seamless recovery
User trade-off: compute cycles vs cyber risk (exposure)
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Cyber Kill Chain
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Resilience Approach: Self Cleansing Intrusion Tolerance
Restoration & Moving Target Defense – How it works
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Constantly Restore Server Integrity
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Additional Advantages of
Resilience & Restoration Approach
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Security
• Reduce data ex-filtration losses
– Disconnect from malicious
site
– Rate modulation on outgoing
data
• IT Early warning
• Respond to high threat intensity
• Software whitelist on steroids
• Reduce SOC ticket response time
• Recovery
• Forensic
System & Network
Management
• Operational Resilience
– No memory leaks
– Apply hot patches – no server
reboot required
– Quick recovery from bad
patch
– Better manage the level of
testing required
• Configuration management
• Automatically replace
compromised VMs
• Supports disaster recovery
Conclusion
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• SDN security requires a resilience approach
• SDN controller needs particular focus
– Static implementations lead to asymmetric advantage
for attacker
– Successful persistent attacks can damage the network
• SDN transactions are short – enables
automated restoration
• Cost of computer cycles is falling - supports a
restoration strategy