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Virus and antivirus

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Virus and antivirus

  1. 1. VIRUS , ANTIVIRUS & FIREWALL  Group Members:  Somesh Mahale  Tejas Patil  Harshal Joshi  Samiran Amrutsagar  Umesh More
  2. 2. VIRUS • Computer viruses are small software programs designed to transfer from one computer to another. “A virus is simply a computer program that is intentionally written to attach itself to other programs and replicate whenever those programs are executed ”. • Viruses can easily spread by e-mail attachment or instant messaging messages. • Virus can be spread by downloading unnecessary files from Internet. • Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files.
  3. 3. HISTORY  The creeper virus was first detected on ARPANET, in early 1970s  Propagated from TENEX operating system.  The first pc virus was a boot sector virus called “brain”, created by Basit and Amjad Farooq Alvi, in 1986, Lahore, Pakistan.  This virus copies itself from the software.
  4. 4. TRADITIONAL COMPUTER VIRUSES  First widely seen in the late 1980s,  Technology development encouraged virus creation.  Development of personal computers.  Due to the internet.  Development of floppy disks.
  5. 5. HOW VIRUS WORKS?  When we run infected program it loads into the memory and stars running as well. It also has an ability to infect other programs.  When virus runs unidentified programs it adds itself to it.  When we transfer some programs and files to our friend either through email, cd, and floppy disk, our friend’s computer can also be affected as well.
  6. 6. TYPE  Trojan horses – A Trojan horse is a simple computer program. The program damage when we run it. It can even damage hard disk. Trojan horses can’t replicate automatically.  E-mail viruses – An e-mail virus travels as an attachment to email- message and usually replicates itself by automatically mailing itself to the entire contact list on our email address book. Some e-mail viruses don't even require a double- click. If we hit once, it directly passes to system.
  7. 7. SAFETY MEASURES FOR VIRUSES  Run a secure operating system like UNIX.  Buy virus protection software and install in PCs.  Avoid program from unknown sources (INTERNET).  Use commercial software.  For Microsoft application, Macro Virus Protection should be enabled.  Never download unknown email attachment.  Block receiving and sending executable codes.  Solution is Antivirus software
  8. 8. ANTIVIRUS-SOFTWARE  Softwares that attempt to identify and eliminate computer viruses and other malicious software (malware).  Sophisticated - But virus creators are always one step ahead.  Detection - This is the key to antivirus software.
  9. 9. DETECTION TECHNIQUES  Scanning  Integrity Checking  Scanning is the most commonly used technique in antivirus software.
  10. 10. SCANNING  Also known as Virus Dictionary Approach.  Scanner scans the hard disk, memory, boot sector for code snippets.  If code snippet in a file matches any virus in the dictionary, appropriate action is taken.
  11. 11. SCANNING  Advantages - Viruses can be found before execution. - False alarms are rare. - Quick at detecting known viruses.  Disadvantages - Polymorphic Viruses. - Virus executes at least once. - Continuous updates necessary.
  12. 12. What is a firewall? A firewall is a device (or software feature) designed to control the flow of traffic into and out-of a network. In general, firewalls are installed to prevent attacks.
  13. 13. Edge Firewall An edge firewall is usually software running on a server or workstation. An edge firewall protects a single computer from attacks directed against it. Examples of these firewalls are: ZoneAlarm BlackIce IPFW on OSX
  14. 14. Firewall Appliance An appliance firewall is a device whose sole function is to act as a firewall. Examples of these firewalls are: Cisco PIX. Netscreen series.
  15. 15. Router/Bridge based Firewall A firewall running on a bridge or a router protects from a group of devices to an entire network. Cisco has firewall feature sets in their IOS operating system. Computer-based Network Firewall A network firewall runs on a computer (such as a PC or Unix computer). These firewalls are some of the most flexible. Many free products are available including IPFilter (the first package we tried), PF (the current package we are using found on OpenBSD 3.0 and later) and IPTables (found on Linux). Commercial products include: Checkpoint Firewall-1. Apple OSX includes IPFW (included in an operating system you gotta purchase). Network Firewall
  16. 16. Protect a wide range of machines from general probes and many attacks. Provides some protection for machines lacking in security. Why use a firewall ?
  17. 17. Blocks packets based on: Source IP Address or range of addresses. Source IP Port Destination IP Address or range of addresses. Destination IP Port Some allow higher layers up the OSI model. Other protocols (How would you filter DecNET anyway?). Common ports 80 HTTP 443 HTTPS 20 & 21 FTP (didn’t know 20 was for FTP, did you?) 23 Telnet 22 SSH 25 SMTP

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