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HoneyNets, Intrusion Detection
Systems, and Network Forensics
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Introduction
• Definition of a Honeynet• Concept of Data Capture and Data Control• Generation I vs. Generation II Honeynets• Description of the Georgia Tech Campus Network• Current Vulnerabilities on the Internet• Current Tools to Protect Networks
Firewalls Intrusion Detection Systems (IDS)
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Shortcomings Associated with Firewalls
1. The firewall cannot protect against attacks that bypass it, such as a dial–in or dial-out capability.
2. The firewall at the network interface does not protect against internal threats.
3. The firewall cannot protect against the transfer of virus–laden files and programs
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Shortcomings Associated with Intrusion Detection Systems
1. Increase Complexity of Security Management of Network
2. High Level of False Positive and False Negative Alerts
3. Must Know Signature or Anomoly Detection Pattern
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Definition of a Honeynet
• Network Established Behind a Reverse Firewall
• Captures All In-Bound and Out-Bound Traffic
• Any Type of System
• Network is Intended To Be Compromised
• All Honeynet traffic is suspicious
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Data Capture and Data Control
• Data Capture Collect all information entering and leaving the
Honeynet covertly for future analysis
• Data Control Covertly protect other networks from being
attacked and compromised by computers on the Honeynet
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Generation I vs. Generation II
• GEN I Honeynet Simple Methodology, Limited Capability Highly effective at detecting automated attacks Use Reverse Firewall for Data Control Can be fingerprinted by a skilled hacker Runs at OSI Layer 3
• GEN II Honeynet More Complex to Deploy and Maintain Examine Outbound Data and make determination to block,
pass, or modify data Runs at OSI Layer 2
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Georgia Tech Campus Network• 15000 Students, 5000 Staff, 69 Departments • 30000-35000 networked computers on campus• Average data throughput 600Mbps/4 terabytes per
day• NO FIREWALL BETWEEN CAMPUS &
INTERNET! Why? Requirement for Academic Freedom, high
throughput However, individual enclaves within Georgia Tech use
firewalls
• IDS is run at campus gateway Out of band monitoring and follow-on investigation
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Establishment of the Honeynet on the Georgia Tech Campus
• Established in Summer of 2002
• Uses Open Source Software
• Initially Established As One Honeynet Machine behind the firewall
• IP Address Range Provided by Georgia Tech Office of Information Technology (OIT)
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Georgia Tech Honeynet
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Hardware and Software
• No Requirement for State of the Art Equipment (Surplus Equipment)
• No Production Systems• Minimum Traffic• Use Open Source Software (SNORT,
Ethereal, MySQL DB, ACID)• Use Reverse Firewall Script Developed by
Honeynet.org
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Intrusion Detection System Used with HoneyNet
• SNORT Open Source Signature-Based, with Anomaly-Based Plug-in
Available Can Write Customized Signatures
• Run Two Separate SNORT Sessions One Session to Check Against Signature Database One Session to Capture All Inbound/Outbound Traffic
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Analysis Console for Intrusion Detection (ACID)
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Logging and Review of Data
• Honeynet Data is stored in two separate locations Alert Data is stored in SQL database Packet Capture Data is stored in a daily archive file
• Data Analysis is a time consuming process In our Experience: One hour/day to analyze traffic One hour of attack traffic can result up to one week of
analysis
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Ethereal Analysis Tool
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Exploitations Detected on the Georgia Tech Honeynet
• 36 possible exploited machines have been detected at Georgia Tech in previous 9 months (through June 2003)
• A report is made to OIT on each suspected compromise
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Identification of a System with a Compromised Password
• Previously Compromised Honeynet Computer Continued to Operate as Warez Server
• Another Georgia Tech Computer Connected to the Warez Server
• Investigation Revealed that Password had been Compromised on Second Georgia Tech Computer
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Detection of Worm Type Exploits
• GEN I Honeynet Well-Suited to Detect Worm Type Exploits Repeated Scans targeting specific ports Analyze captured data for time lapses
• Ability to Deploy Specific Operating System on Honeynet
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Exploitation Pattern of Typical Internet Worm
• Target Vulnerabilities on Specific Operating Systems
• Localized Scanning to Propagate (Code Red) 3/8 of time within same /16 network 1/2 of time within same /8 network 1/8 of time random address
• Allows for Quick Infection Within Internal Networks with High Concentration of Vulnerable Hosts
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Georgia Tech Honeynet Gen II
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Initial Observations of Gen II Honeynet
• Configuration is more complex than Gen I
• Must use variants of Linux 2.4 kernel in order to run Sebek keystroke logger capability
• Data must continue to be monitored on a daily basis
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Honeynet Portscan ActivityPort 1434 (MS-SQL) scans
0
200
400
600
800
1000
1200
Jul_
31
Aug_06
Aug_29
Aug_21
Sep_09
Sep_17
Sep_24
Oct
_12
Oct
_04
Oct
_28
Oct
_20
Nov_
08
Nov_
09
Nov_
19
Nov_
21
Nov_
29
Dec_
05
Dec_
13
Dec_
21
Dec_
29
Jan_06
Jan_14
Jan_22
Jan_28
Feb_05
Feb_13
Feb_20
Feb_27
Mar_
07
Mar_
13
Mar_
19
Mar_
27
Apr_
04
Apr_
12
Apr_
20
Jun_10
Sep_10
Series1
• Date Public: 7/24/02 Date Attack: 1/25/03
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Honeynet Portscan Activity
• Date Public: 7/16/03 Date Attack: 8/11/03
Port 135 (MS-BLASTER) scans
0
500
1000
1500
2000
2500
3000
3500
Series1
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Honeynet Portscan Activity
• Date Public: 8/15/2003 Date Attack: 8/22/03
Port 554 (RTSP) scans
0
5
10
15
20
25
30
35
40
5/2
0/2
003
5/2
7/2
003
6/3
/2003
6/1
0/2
003
6/1
7/2
003
6/2
4/2
003
7/1
/2003
7/8
/2003
7/1
5/2
003
7/2
2/2
003
7/2
9/2
003
8/5
/2003
8/1
2/2
003
8/1
9/2
003
8/2
6/2
003
9/2
/2003
9/9
/2003
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Conclusions on HoneyNets
• Honeynet Assists in Maintaining Network Security
• Provides Platform for Research in Information Assurance and Intrusion Detection
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IDS - Purpose
• Misuse detection
• Anomaly detection
• Conduct forensics
• Network traffic recording and analysis
• Intellectual property protection
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IDS Strategies
• Signature-based (misuse detection) pattern matching cannot detect new attacks low false positive rate
• Anomaly-based (statistical-based) activity monitoring has the ability to detect new attacks higher false positive rate
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IDS Deployment
• Network-based Inspect network traffic Monitor user activity (packet data)
• Host-based Inspect local network activity OS audit functionality Monitor user activity (function calls)
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Example IDS:Snort
• Sniffer
• Packet logger
• IDS
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Snort Rules
Example 1: “log tcp traffic from any port going to ports less than or equal to 6000”log tcp any any -> 192.168.1.0/24 :6000
Example 2: RPC alert call
alert tcp any any -> 192.168.1.0/24 111 (rpc: 100000, *,3; msg:RPC getport (TCP);)
see Snort Users Manual for more information
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Defeating the IDS
• Encryption• Insertion/evasion attacks (requires complete
reassembly of packets and knowledge of end system exception handling)
• DoS attack (CPU, memory, bandwidth, false positives)
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Signs of Intrusion
• Unaccountable disk utilization
• Unaccountable file system modification
• Unaccountable CPU utilization
• Network saturation
• Unknown process using sockets
• Abnormal network/system activity
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Forensics
• After the attack• Obtain:
Attacker(s) IP(s) Time of attack Victim IP, OS, and targeted service Attacker’s activity Attacker’s objective Damage assessment
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Forensic Guidance
• Photograph complete system• Take detailed notes• ID and secure all compromised systems• Preserve evidence (UNIX)
who (who logged on) ls (list of files) ps (list of processes) lsof (open file handles) find (modified files)
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Forensic Guidance
• System operations can lie (rootkits)
• Retain a provable chain of custody for evidence
• Make bit-image copy of hard drive and verify it
• Analyze