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Intrusion Detection Research. Stephen Huang Sept. 20, 2013. News. http://arstechnica.com/security/2013/09/meet-hidden-lynx-the-most-elite-hacker-crew-youve-never-heard-of/. Jobs. http://www.homelandsecuritynewswire.com/dr20130809-cybersecurity-jobs-average-over-100-000-a-year.
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Intrusion Detection Research Stephen Huang Sept. 20, 2013
http://arstechnica.com/security/2013/09/meet-hidden-lynx-the-most-elite-hacker-crew-youve-never-heard-of/http://arstechnica.com/security/2013/09/meet-hidden-lynx-the-most-elite-hacker-crew-youve-never-heard-of/
Jobs • http://www.homelandsecuritynewswire.com/dr20130809-cybersecurity-jobs-average-over-100-000-a-year
Intrusion Detection Research • Objective: To protect the infrastructure and the integrity of the computer systems and its data. • Assumptions: • Hackers are able to establish a connection session to the victim machine. • Packets are exchanged between the originating source and the victim. • Data may be encrypted.
Attack Victim Attacker
Stepping-Stone Attack Stepping-Stone Victim Attacker
Our Strategy Stepping-Stone Victim Attacker
Our Solutions 1 & 2 • Refuse to be a Stepping-Stone. Identifying a host being used as a stepping-stone (Stepping-Stone Detection). • Detecting long downstream connections chains. • Comparing incoming and outgoing streams of packets for similarity.
Long Connection Chain Detection Matching Send- and Echo- Packets to compute the Round-Trip Time (RTT).
Victim Host Protection Connection Chain Attacker Visible Hosts Victim
Solution 3 • Refuse to be a victim. Identifying a host being attacked through a stepping-stone chain. • Examining the behavior of long connection chains.
Challenges • Intruder’s evasion techniques, • Chaffing • Time jittering • New Technology • TOR
Evasion Attack S1 Y Stepping-Stone Correlation Decision N S2 Normal Correlation-Based Approach
Evasion Attack S1 Chaffed ? Y Stepping-Stone Correlation Decision N S2 Normal Correlation-Based Approach
Solution 4 • If one jitter or chaff a traffic stream enough, the pattern of the packets becomes different from the norm.
Countering the Evasion Y Chaff Detection Decision Attack S1 N Y Stepping-Stone Correlation Decision N S2 Normal
TOR • TOR (The Onion Router) is a network of virtual tunnels that allows people to improve their privacy and security on the Internet. • Anonymity Online.
Issues • Users have an anonymous way to connect to a host. • So do the hackers! More convenient. • Can we detect when a user is trying to sign on to our server by going through TOR? • There may be legitimate reason to do so, but certainly very suspicious.
Typical TCP Connection SYN SYN-ACK ACK HTTP GET
TOR HTTP Connection begin {relay} SYN SYN-ACK {relay} ACK connected {relay} HTTP GET HTTP GET
Summary • Real-time intrusion detection is critical in protecting data and integrity of computer systems. • It is possible to detect a large percentage of cases by using various methods. • Intruders have developed techniques to evade detection. We have to come up with countermeasures.