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Distributed IDS. The implementation of a Distributed Intrusion Detection System over a medium scale open network where the focus is availability of services. Darian Jenik - Network Management Queensland University of Technology. What we hope to achieve:.
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Distributed IDS • The implementation of a Distributed Intrusion Detection System over a medium scale open network where the focus is availability of services. • Darian Jenik - Network Management Queensland University of Technology
What we hope to achieve: • Learn about the nature of traffic flowing on the network. • Catch attempts to compromise host security. • Detect compromised hosts on the network. • Discover holes and incorrect configurations on existing services. • Take a proactive rather than reactive approach to dealing with security issues.
What IDS is not: • IDS in NOT security – • For security you need: • Good security policy that is both documented and adhered to. • Good security practice by system administrators. • Hardened perimeter firewalls and “DMZ” firewalls. • IDS is not a “product”. • IDS is not a “sensor”.
What Information can it provide: Denials, scans, vulnerable services, etc…. Other input sources (Tripwire, syslog, firewall…) Cross referencing allows individual events that seem innocent to take up more meaning in context.
Where do we put the sensor: Traditionally – gateway(s) Port Mirroring ? (50+ datacabinets) Preferably everywhere This would normally cost $$$$$ but open source makes this possible
The scale of the problem • Approximately 10000 hosts 100 web servers 300 “servers” of other type • Students • System Administrators • IAS
Outside 1 Outside 2 Servers GW GW Inside 1 10meg -> 1 Gig GW Inside 2 User hosts The scale of the problem - simplified
Outside 1 Outside 2 Inside 1 10meg -> 1 Gig Inside 2 The scale of the problem contd….. Bad!! Servers Bad!! GW GW GW User hosts
Outside 1 Outside 2 Inside 1 10meg -> 1 Gig Inside 2 The scale of the problem contd….. Servers GW GW GW Worse!! Worse!! User hosts
Outside 1 Outside 2 Inside 1 10meg -> 1 Gig Inside 2 The scale of the problem contd….. Servers GW GW GW User hosts
Outside 1 Outside 2 Inside 1 10meg -> 1 Gig Inside 2 The scale of the problem contd….. Servers GW GW GW User hosts
Dealing with the volume of information • Manually examine each incident (initially). • Classify and build up a database of false positives. • Use the power of the SQL database to look for patterns and “repeats”
IDS should perform the following tasks • Detect known violations to host integrity by passively watching network traffic. • Respond to attempted violations by blocking external IP addresses. • Respond to probes from outside by blocking external IP addresses. • Find and report usage inconsistencies that indicate account/quota theft. • Detect violations by monitoring information (web pages etc….) • Help log and establish traffic/host usage patterns for future reference and comparison
Respond to attempted violations by blocking external IP addresses. • Make sure the IDS is able to respond and send commands to firewalls and/or hosts. • IDS sends RST packets to both ends of the connection. • IDS is able to insert rules into border firewall.
Respond to probes from outside by blocking external IP addresses. • Attempts to open ports on servers that are not enabled. • Make “flypaper” IP addresses that have never been used for anything that serve to pickup slow probes.
Supporting information sources that can be fed into the database. • Central syslog collecting and analysis. • Tripwire • “Nmap” database • Performance and Usage analysis.
Open Source • Just about any platform(Including windows) • Many plugins and external modules. • Frequent rules updates.
Snort Plugins • Databases • mySQL • Oracle • Postgresql • unixODBC • Spade (Statistical Packet Anomaly Detection engine) • FlexResp (Session response/closing) • XML output • TCP streams (stream single-byte reassembly)
Snort Add-ons • Acid(Analysis Console for Intrusion Detection) - PHP • Guardian – IPCHAINS rules modifier.(Girr – remover) • SnortSnarf - HTML • Snortlog – syslog • “Ruleset retreive” – automatic rules updater. • Snorticus – central multi-sensor manager – shell • LogSnorter – Syslog > snort SQL database information adder. • + a few win32 bits and pieces.
Snort + Acid = ? • Acid is a Cert project. • Pretty simple PHP to mySQL • Quite customizable. • Simple GUI for casual browsing.
Securityfocus • Whitehats • CVE
URLS • www.snort.org • http://www.cert.org/kb/acid/ • www.whitehats.com(Intrusion signatures data) • www.securityfocus.com(Intrusion signatures data) • http://cve.mitre.org/(Intrusion signatures data) • http://www.psionic.com/(logcheck + hostsentry)