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Protecting Network Quality of Service against Denial of Service Attacks. Douglas S. Reeves S. Felix Wu Chandru Sargor N. C. State University / MCNC October 6, 1999 Tolerant Networks Program BAA99-10 Kickoff Meeting. Quality of Service - a New Capability for Packet-Switching.
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Protecting Network Quality of Service against Denial of Service Attacks Douglas S. Reeves S. Felix Wu Chandru Sargor N. C. State University / MCNC October 6, 1999 Tolerant Networks Program BAA99-10 Kickoff Meeting
Quality of Service - a New Capability for Packet-Switching • New services • Guaranteed minimum bandwidth • Guaranteed maximum delay • Guaranteed maximum loss rate • Guaranteeing QoS for a “flow” requires providing adequate resources
DST SRC IntServ / RSVP Operation PATH messages RESV messages Tspec = 5M Tspec = 5M ADspec = 5M ADspec = 4M ADspec = 3M That looks fine to me….. Reserve 3M Reserve 3M
DiffServ DATA flow SRC1 DST1 SRC2 DST2 Service Agreement and Traffic Agreement
Quality of Service - A New Vulnerability • Normal users will try to get maximum QoS without regard to others • Malicious users will try to deny quality of service for others
The ARQOS Project • Selective verification of reservation signaling (SVR) • Congestion pricing of scarce resources ($$$) • Monitoring of data flows, and integration with intrusion detection (IDS)
DST SRC SVR: Attacking ADSpec ADSpec = 200M ADSpec = 5M That looks fine to me….. Reserve 200M Reserve 5M
SVR: IETF RSVP SecurityCurrent solution proposed by Fred Baker • All routers, even including those not on the path, share the same “key table” • Hop-by-hop authentication of messages • outsiders tampering with packets will be detected, but corrupted insiders will not be detected
SVR: IETF RSVP Security (cont.) Sharing a secret key A ADSpec B A & B trust each other; If A is compromised and sends a faulty ADSpec, there is no way for B to know about it
SVR: Our Approach DST SRC ADSpec = 200M ADSpec = 5M Correlation and Verification of the Correctness Properties
SVR: Verification of Reservations • No need to introduce new features to RSVP, other existing protocols • Do not need to install verification agents in every router • Capable of detecting insider attacks
SVR: Status • Identified types of possible attacks on RSVP signals • Solutions for detecting the most important types of attacks • Now implementing attacks and solutions
$$$: Competing for Services "You can have 5M, 2M, or 1M, at no cost; what do you want, and for how long?” Service Provider: Network Resources 5M 5M 5M 5M 5M 5M Users: “We all want 5M, from now on!”
$$$: Influencing Behavior • Disincentives for bad behavior -- users incur costs for resource usage • Incentives for good behavior -- profits for service providers
$$$: Competition (cont.) Service Provider: “5M costs $3/min, 2M costs $2/min, 1M costs $1/min.” Network Resources 1M @$1 5M @$3 1M @$1 5M @$3 5M @$3 2M @$2 Users:
$$$: Pricing of Resources • Price is right when demand = supply • Flexibility • combinations of resources and services • User endowments for non-monetary goals • How are prices set, by whom, and how are they distributed?
$$$: Goals and Assumptions • Fairness vs. “maximum aggregate utility” • The time and data scales for which this is useful • Real money, or play money? • Charging senders, or receivers • The overhead of billing and accounting
$$$: Status • Pricing method • Integration with RSVP • Integration with DiffServ • Infrastructure
IDS: Attacks on the Data Flow • From a malicious host (external to network) • spoof high priority data flow packets • send large amounts of data to ingress router to overload it • From a compromised ingress router • admit/discard traffic in violation of service agreement • inappropriate marking of admitted traffic
IDS: Possible Attacks (cont.) • delay/drop packets from selected flows • generate additional traffic to degrade overall network QoS • From a compromised core router • randomly re-mark flows • delay/drop packets from selected flows • generate additional traffic to degrade overall network QoS
IDS: Intrusion Detection System Security Management Entity SNMPv3 Rule-Based Analyzer Profile-Based Analyzer IDS MIB Decision Module Filtering Engine Network
IDS: Detecting Re-marked Packets • Downstream IDS will detect anomalous change in IP header • raise alarm via SNMP • Security management entity will receive alarms from IDS entities and correlate them • Security management entity will query other routers on the path to isolate compromised router
IDS: Status • Enhance JiNao implementation to make it protocol independent • originally targeted for OSPF attack detection • now can be used to detect attacks against any protocol • Identification of data flow attacks • Preliminary design of IDS system
Conclusions • Started August ‘99 • Implementing RSVP / DiffServ testbed • Exploring collaborations with vendors