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Introduction to Honeypot, Botnet, and Security Measurement

Cliff C. Zou02/07/06

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What Is a Honeypot?

Abstract definition: “A honeypot is an information system resource whose value lies in unauthorized or illicit use of that resource.” (Lance Spitzner)

Concrete definition: “A honeypot is a faked vulnerable system used for the purpose of being attacked, probed, exploited and compromised.”

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Example of a Simple Honeypot

Install vulnerable OS and software on a machine

Install monitor or IDS software Connect to the Internet (with global IP) Wait & monitor being scanned,

attacked, compromised Finish analysis, clean the machine

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Benefit of Deploying Honeypots

Risk mitigation: A deployed honeypot may lure an attacker away

from the real production systems (“easy target“).

IDS-like functionality: Since no legitimate traffic should take place to or

from the honeypot, any traffic appearing is evil and can initiate further actions.

Attack analysis: Find out reasons, and strategies why and how you

are attacked.

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Benefit of Deploying Honeypots

Evidence: Once the attacker is identified all data captured

may be used in a legal procedure. Increased knowledge:

By knowing how you are attacked you are able to enlarge your ability to respond in an appropriate way and to prevent future attacks.

Research: Operating and monitoring a honeypot can reveal

most up-to-date techniques/exploits and tools used as well as internal communications of the hackers or infection or spreading techniques of worms or viruses.

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Honeypot Classification

High-interaction honeypots A full and working OS is provided for being

attacked VMware virtual environment

Several VMware virtual hosts in one physical machine

Low-interaction honeypots Only emulate specific network services No real interaction or OS

Honeyd

Honeynet/honeyfarm A network of honeypots

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Low-Interaction Honeypots

Pros: Easy to install (simple program) No risk (no vulnerable software to be

attacked) One machine supports hundreds of honeypots

Cons: No real interaction to be captured

Limited logging/monitor function Easily detectable by attackers

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High-Interaction Honeypots

Pros: Real OS, capture all attack traffic/actions Can discover unknown attacks/vulnerabilites

Cons: Time-consuming to build/maintain Time-consuming to analysis attack Risk of being used as stepping stone High computer resource requirement

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Honeynet A network of honeypots High-interaction honeynet

A distributed network composing many honeypots “Collapsar: A VM-Based Architecture for Network Attack

Detention Center”, Usenix’04

Low-interaction honeynet Emulate a virtual network in one physical machine Example: honeyd

Mixed honeynet “Scalability, Fidelity and Containment in the

Potemkin Virtual Honeyfarm”, presented next week

Reference: http://www.ccc.de/congress/2004/fahrplan/files/135-honeypot-forensics-slides.ppt

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What Is a Botnet?

A network of compromised computers controlled by their attacker Users on zombie machines do not know

The main source for many attacks now Distributed Denial-of-Service (DDoS)

Extortion Email spam, phishing Ad-fraud User information: document, keylogger, …

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How to Build a Botnet?

Infect machines via: Internet worms, viruses Email virus Backdoor left by previous malware Trojan programs …

Bots phone back to receive command

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Botnet Architecture Bot controller

Usually using IRC server (Internet relay chat) Dozen of controllers for robustness

bot bot

botcontroller

attacker

bot

botcontroller

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Botnet Monitoring

Hijack one of the bot controller DNS provider redirects domain name to

the monitor Still cannot cut off a botnet (dozen of

controller) Can obtain most/all bots IP addresses

Let honeypots join in a botnet Can monitor all communications No complete picture of a botnet

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Security Measurement

Monitor network traffic to understand/track Internet attack activities

Monitor incoming traffic to unused IP space

TCP connection requests UDP packets

Unused IP space

Monitoredtraffic

Internet

Local network

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Refining Monitoring

TCP/SYN not enough (IP, port only) Distinguish different attacks

Low-interaction honeypots (honeyd) Obtain the first attack payload by replying SYN/ACK “Internet Motion Sensor” presented next week

High-interaction honeypots TCP Reset packets

Backscatter from spoofed DoS attack victims “Inferring Internet Denial-of-Service Activity”, presented later

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Remote fingerprinting

Actively probe remote hosts to identify remote hosts’ OS, physical devices, etc OSes service responses are different Hardware responses are different

Purposes: Understand Internet computers Remove DHCP issue in monitored data

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Data Sharing: Traffic Anonymization

Sharing monitored network traffic is important Collaborative attack detection Academic research

Privacy and security exposure in data sharing Packet header: IP address, service port exposure Packet content: more serious

Data anonymization Change packet header: preserve IP prefix, and … Change packet content