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Investigation and Evaluation of Systems for Generating Automatic Alerts Using Honeynet Data. Master’s Thesis Seminar Presentation 9.8.2005 Esko Harjama. Contents. Background Problem statement & Methodology Introduction Alerting issues Automatic Isolation Function Evaluation Prototyping
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Investigation and Evaluation of Systems for Generating Automatic Alerts Using Honeynet Data Master’s Thesis Seminar Presentation 9.8.2005 Esko Harjama
Contents • Background • Problem statement & Methodology • Introduction • Alerting issues • Automatic Isolation Function • Evaluation • Prototyping • Results & Conclusions
Background • Supervisors • Prof. Jörg Ott (Netlab), • Prof. Guillame Urvoy-Keller (Eurecom) • Instructor • M.Sc. Idar Kvernevik (F-Secure Oyj) • Carried out as a project for F-Secure
Problem Statement • Honeynets gather information on illicit network traffic and attacks against Honeynet computers • These attacks need to be recognized and investigated • Since 24/7 system monitoring is not practical, an effective alerting system is required to complement monitoring processes • The problem is • How to implement alerting • Where to deploy it • What information and rules should be used to decide when to trigger alerting • Is there need to isolate the computer in addition to alerting and in what cases
Methodologies used • Literature study • IDS, Honeypot and alerting background • Investigation of existing tools and methods for alerting • Evaluation • Evaluation of the pre-selected tools based on criteria • Prototyping • Prototyping the selected solution in the reference environment • Analysis of the results
Introduction: Intrusion Detection Systems, Honeypots • IDS • Monitors network traffic and reports on specified behavior • IDS process: capture, analysis, classification, report, reaction • Example: Snort, a popular open-source IDS based on pattern-matching • Honeypot • Computers placed in the network to ”lure” attackers • Networks of Honeypots form ”Honeynets” • Offer information on specific attacks and statistics • Example project: Honeynet.org alliance
Alerting issues • Alert response processes • Push/Pull ideology • False positives/negatives • Alerting approaches • Log file vs. database monitoring • Information sources • Snort alerts, gateway syslog/iptables logs, upstream end-user data, remote Honeynets • Alerting tools • Snort tools; reporting, configuration, ”alerting” • Log-monitoring applications • Alerting methods • Log, email, SMS, etc
Automatic Isolation Function • Reasoning • Prevents further attacks from the compromised computer against 3rd parties • Prevent the attacker from erasing any attack methods and details from the computer • Prevent undesired actions inside the Honeynet • Conditions for isolation • Trend increase in the number of attacks/packets • Specific, defined attack behavior • Possible points of isolation • Gateway • Host
Selected tool: Simple Event Correlator (SEC) • Selected because of flexibility in configuration, features suit our needs well, lack of GUI is the only downside. • SEC is a perl program for log-monitoring, run from the shell • Flexible rule structure based on regular expressions • Complemented with PigSentry for new alert and trend increase monitoring • Output can be piped also to log, email and SMS
Prototyping • At the moment, SEC and PigSentry have been running in the reference setup for a couple of weeks, monitoring Snort and Pigsentry logs • Alerts on: • Snort high priority alerts • New alerts and trend increases (Pigsentry) • Especially trend increases are useful • Special alert conditions can also be added • Looks like alerting requires thresholding in all cases, in case of a compromise, alerts quickly escalate and create lots of alerts
Results & Conclusions (so far) • The selected method works for alerting purposes and is pretty flexible for using all kind of data and different output methods • Definition of the monitoring processes and the conditions for triggering alert conditions are problematic • External alerting features are useful in the Honeynet setup, but the tuning of the alerting rules is important • Isolation function depends also on the definition of thr triggering conditions, needs more investigation. • More information on the Honeynet events is needed to better configure the set of rules test period ongoing