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2 What is security? Computer Security deals with the prevention and detection of, and the reaction to, unauthorized actions by users of a computer system or network.

3 Attacks/Threats Physical Access Modification Denial of Service Invasions of Privacy

4 Physical Attacks Hardware theft File/Information Theft Information modification Software installation

5 Access Attacks Attempt to gain information that the attacker is unauthorized to see Password pilfering An attack against confidentiality Snooping Eavesdropping Interception

6 Modification Attacks An attempt to modify information an attacker is not authorized to modify An attack against information integrity Changes Insertion Deletion

7 Denial-Of-Service Attacks Deny the use of resources to legitimate users of a system Denial of access to information Denial of access to applications Denial of access to systems Denial of access to communications

8 Privacy Attacks Collection of information about you your computer configuration your computer use your surfing habits

9 Malware Trap Door Logic Bombs Trojan Horses Worms Bacteria Viruses Mobile Code

10 Malware – collection of techniques/programs that produce undesirable effects on a computer system or network Differentiate based on Needs host program Independent Replicate Don’t replicate

11 Malware Needs Host Program Independent Logic Bomb WormsBacteriaTrapdoor Trojan Horse Virus

12 Worms Programs that use network connections to spread from system to system Once active on a system can behave as another form of malware Propagates Search for other systems to infect Establish connection with remote system Copy itself to remote system and executes

13 The Great Worm Robert Morris released the most famous worm in 1988 Crashed 6000 machines on the Internet (10%) Exploited bug in fingerd program Bug in worm crashed machines which prevented the worm from spreading Estimated damage $100 million Three years probation, 400 hrs community service, $10,500 fine

14 Bacteria Programs that do not explicitly damage files Sole purpose is to replicate themselves within a system Reproduce exponentially taking up Processor capacity Memory Disk space

15 Viruses Infect other programs by modifying them First one written in 1983 by USC student Fred Cohen to demonstrate the concept Approximately 53,000 exist Modification includes copy of virus

16 How Virus are spread Peer to peer networks Via attachments Via media FTP sites Chat and instant messaging Commercial software Web surfing Illegal software

17 Types of Viruses Parasitic Traditional virus and most common Attaches itself to executable files and replicates Memory resident Lodges in memory as part of OS Infects every program that executes

18 Boot sector Infects master boot record or boot record Spreads when system boots Seldom seen anymore Stealth Designed to hide itself from detection by antivirus software

19 Polymorphic Mutates with every infection Functionally equivalent but distinctly different bit patterns Inserts superfluous instructions or interchange order of independent instructions Makes detection of signature of virus difficult Mutation engine creates random key and encrypts virus Upon execution the encrypted virus is decrypted and then run

20 Macro Viruses Make up two thirds of all viruses Platform independent Word documents are the common vehicle rather than executable code “Concept” 1995 first Word macro virus Easily spread

21 Melissa Virus March 1999 Spread in Word documents via Once opened virus would send itself to the first 50 people in Outlook address book Infected normal.dot so any file opened latter would be infected Used Visual Basic for applications Fastest spreading virus ever seen

22 Antivirus software Some of the common methods used are checksumming and signature based scanning. Now a days antivirus softwares use a method called Heuristics. Limits ability of virus to update files The common antivirus softwares available in the market are

23 Virus Detection and Prevention Tips Do not open an from an unknown, suspicious or untrustworthy source Do not open any files attached to an Turn off preview pane in client Enable macro virus protection in all your applications Beware of pirated software Don’t accept files while chatting or messaging

24 Do not download any files from strangers. Exercise caution when downloading files from the Internet. Turn on view file extensions so you can see what type of file you are downloading Save files to disk on download rather than launch application Update your anti-virus software regularly. Back up your files on a regular basis.

25 Privacy Cookies Spyware

26 Cookies A cookie is a piece of text-based information transmitted between a Web site (server) and your browser Saved on your hard drive Netscape – cookies.txt IE – separate files in cookies folder

27 Sent by Web site for future retrieval Used to maintain state Can be Persistent and have expiration date Session only Third party Transferred via HTTP Headers JavaScript Java Applications with HTML content

28 How to disable cookies in MS Internet Explorer V6 – Default

29 Spyware

30 Spyware Spyware is software/hardware that spies on what you do on your computer Often is it employs a user's Internet connection in the background (the so- called "backchannel") without their knowledge or explicit permission. Installed without the user’s knowledge with shareware/freeware

31 Spyware Capabilities Record addresses of Web pages visited Record recipient addresses of each you send Record the sender addresses of each you receive Recording the contents of each you send/receive Corporations to monitor computer usage of employees Computer crackers to capture confidential information Parents to monitor use of family computer Advertising and marketing companies to assemble marketing data to serve personalized ads to individual users Who uses SPYWARES?

32 What haven’t we covered? Security in the wireless environment Authentication systems and their vulnerabilities Operating systems configuration Network security Security Appliances privacy

33 Thank you for attending BY DWITIKRUSHNA NAYAK 24I&E/2K