DEFENSE AGAINSTBOTNETS

Botnets :- IntroductionTypes of BotnetsReal World Scenarios

Defense :-Detection of BotnetsCounter Measures

STRUCTURE

INTRODUCTION

RoBot Network consists of a software stealthily installed on many computers(zombies) remotely controlled by a central authority.

Bot Net

IRC BotnetsHTTP BotnetsPeer-to-Peer Botnets

TYPES OF BOTNETS

Internet Relay Chat(IRC) is a type of a messaging service.

IRC Botnets use IRC servers to issue commands.

IRC BOTNETS

IRC BOTNETS

IRC BOTNETS

IRC BOTNETS

IRC BOTNETS

IRC BOTNETS

HTTP BOTNETS

HTTP BOTNETS

PEER-TO-PEER BOTNETS

How can botnets be used :-• Distributed Denial of Service Attacks (DDoS)• Spamming• Sniffi ng Traffi c & Key logging.• Identity Theft• Attacking IRC Chat Networks• Hosting of Illegal Software• Google AdSense Abuse & Advertisement Addons• Manipulating online polls

REAL WORLD SCENARIO

PassiveData gathered through observation.• Packet Inspection• Analysis of flow records• Analysis of SPAM Attacks

ActiveDetection by being involved i.e. interacting with the botnet.(drawback)Can result in DDOS attack against the analyst, changing of ip’s, protocols etc.• Sink holding• Infiltration• Peer-to-peer botnet enumeration

DETECTION TECHNIQUES

Packet InspectionInspect network data packets

• Match various protocol fields.• Match payload against a predefined pattern of

suspicious content.

Drawbacks:-• Wouldn’t scale• Only known patterns are detected

PASSIVE DETECTION

Analysis of flow recordsTracing network traffi c at an abstract level.Instead of inspecting individual packets communication streams are considered in aggregate form.We look into:- • Source, destination address• Related port no’s• Duration of session• Cumulative size and no of transmitted packets.• Protocol used inside packets.

Advantage:- higher amount of traffi c can be monitored.Eg. ‘Net Flow’ protocol from cisco.

PASSIVE DETECTION

Analysis of SPAM attacks• Spam mails are analyzed and similar templates are

grouped.• These templates can then be matched to a

corresponding botnet.

For this special Honey pots called honey tokens are used .

PASSIVE DETECTION

Honeypot:- It is a trap to detect, deflect or in some manner counter act an attempt at unauthorized use of Information system.

Honey Token:- Spam traps consisting of email addresses with no productive function other than to receive unsolicited emails.

PASSIVE DETECTION

Other Techniques:-• Analysis of log fi les.• Evaluation of anti-virus software feedback.• DNS based approaches.

PASSIVE DETECTION

Sink Holding • Technical countermeasure for cutting off a malicious

control source from rest of the botnet.• Eg. By changing the targeted malicious domain name

so that it points to machine controlled by a trusted party.

ACTIVE TECHNIQUES

Infi ltrationAims to take control of the botnet.

• Hardware- if ip address is known all communications can be wiretapped with the help of hosting company.

• Software- Imitating the communication mechanisms used by the botnet.

ACTIVE DETECTION

Peer-to-peer botnet enumerationRepeatedly querying peers for their neighbor list.

This includes reverse engineering.• Creating a implementation of the botnet to perform

the enumeration task.

ACTIVE DETECTION

Blacklisting• Block all traffi c from included addresses.• Search engine or browser can fi lter or mark such

websites.

Distribution of fake/traceable credentials.• Populate fake data into our records like credit card

details.• Fake data lowers quality of stolen information• Generate mistrust among criminals.

TECHNICAL COUNTERMEASURES

BGP Block holingNull routing malicious hosts to deny traffi c from or to their network.Null-Routing:- It is a process of silently dropping the packets originated from or destined for such addresses.

DNS based countermeasure• Malicious domains can be shut down.• Require court warrant.• Sometimes twitter and rss feeds are used to give

commands, doesn’t work in that case.

TECHNICAL COUNTERMEASURES

Port 25 Blocking Spam mails would not be sent.

Peer to peer counter measurePollute the peer-to-peer listResults in• Loss of overall connectivity• Due to size limitations older original peers will get

replaced by fake peers.

TECHNICAL COUNTERMEASURES

Dedicated laws.User awareness.Use of anti-virus software etc.

SOCIAL COUNTERMEASURES

QUERIES

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THANKS…

STAY SECURE!!!