Computer Viruses & Anti Virus

Presented by,Manoj S. Dongare (4R-45)

Malware

● Malware is a software designed to harm or secretly access a computer system without the owner's informed consent.

● Malware, short for malicious software,also known as pestware.

● In general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code

Types of Malware

● Trojan Horse

● Worms

● Spyware

● Adware

● Backdoor

● Virus

Malware Categories

Trojan horses

● A Trojan horse is simply a computer program. The program claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard disk). Trojan horses have no way to replicate automatically.

Worms

• A worm is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well.

Spyware

● Spyware is malicious computer program that does exactly what its name implies Eg:, spies on you.

● After downloading itself onto your computer either through an email you opened, website you visited or a program you downloaded, spyware scans your hard drive for personal information and your internet browsing habits.

● Some spyware programs contain keyloggers that will record personal data you enter in to websites, such as your login usernames and passwords, email addresses, browsing history as well as sensitive banking and credit information.

Adware

● Adware is any software that, once installed on your computer, tracks your internet browsing habits and sends you popup containing advertisements related to the sites and topics you've visited.

● While this type of software may sound innocent, and even helpful, it consumes and slows down your computer's processor and internet connection speed.

● Additionally, some adware has keyloggers and spyware built into the program, leading to greater damage to your computer and possible invasion of your private data.

Backdoor

● A backdoor is a method of bypassing normal authentication procedures.

● Once a system has been compromised one or more backdoors maybe installed in order to allow easier access in the future.

● Backdoors may also be installed prior to malicious software, to allow attackers entry.

● Crackers typically use backdoors to secure remote access to a computer, while attempting to remain hidden from casual inspection.

● A computer virus is a type of malware that, when executed, replicates by inserting copies of itself (possibly modified) into other computer programs, data files, or the boot sector of the hard drive; when this replication succeeds, the affected areas are then said to be "infected".

● Viruses often perform some type of harmful activity on infected hosts, such as stealing hard disk space or CPU time, accessing private information, corrupting data, displaying political or humorous messages on the user's screen, spamming their contacts, or logging their keystrokes.

Virus

World’s 1st Computer Virus

● The first ever computer virus was developed in 1986 by two Pakistani brothers in Lahore Pakistan.

● It was named “Brain” and was designed by Amjad Farooq Alvi and Basit Farooq Alvi with the intention of discouraging the piracy of a software written by them.

Types Of Computer Virus

• Boot sector virus

• Master Boot Record (MBR) virus

• File infector virus

• Macro virus

BOOT SECTOR VIRUS: Boot sector viruses generally hide in the boot sector, either in the bootable disk or the hard drive. It attaches itself to the primary active partition of the hard disk that is read by the computer upon boot up.

MASTER BOOT RECORD VIRUS: MBR viruses are memory-resident viruses that infect disks in the same manner as boot sector viruses. However it, infects the MBR of the system, gets activated when the BIOS activates the Master boot code. MBR infectors normally save a legitimate copy of the master boot record in an different location.

Types Of Computer Virus

File Infector Virus: File Infector viruses infect program files. Normally infect executable code, such as .COM, .SYS, .BAT and .EXE files. They can infect other files when an infected program is run from floppy, hard drive, or from the network. Many of these viruses are memory resident. After memory becomes infected, any uninfected executable file that runs becomes infected.

Types Of Computer Virus

Types Of Computer Virus

Macro Virus: Macro are mini-programs which make it possible to automate series of operations so that they are performed as a single action, thereby saving the user from having to carry them out one by one. Macro viruses infect files that are created using certain applications or programs that contain macros.They are platform-independent since the virus itself are written in language of the application and not the operating system. They infect documents created from Microsoft Office Word, Excel, PowerPoint and Access files.

Solution to Computer Viruses

An antivirus software is a computer program that identify and remove computer viruses, and other malicious software like Worms and Trojans from an infected computer. Not only this, an antivirus software also protects the computer from further virus attacks.

We should regularly run an antivirus program to scanand remove any possible virus attacks from a computer.

AntiVirus

They can provide real time protection against the installationof spywares on the computer. This type of spyware protectionworks the same way as that of anti-virus protection. It scansand blocks all incoming network threats as it comes across. It can be used solely for detection and removal ofSpyware that has already been installed into the computer.Anti spyware scans the contents of the windows registry,operating system files, and installed programs on computerand will provide a list of any threats found.

Anti-Spyware

Using dictionary Approach:

•The antivirus software examines each and every file in a computer and examines its content with the virus definitions stored in its virus dictionary.

•A virus dictionary is an inbuilt file belonging to an antivirus software that contains code identified as a virus by the antivirus authors.

How an AntiVirus Works…

How an AntiVirus Works…

Using Suspicious Behavior Approach:

•Antivirus software will constantly monitors the activity of all the programs.•If any program tries to write data on an executable file, the antivirus software will flag the program having a suspicious behavior, means the suspected program will be marked as a virus.•The advantage of this approach is that it can safeguard the computer against unknown viruses also.•The disadvantage is that it may create several false alerts too.

Popular Anti-Virus And Anti-Spyware Softwares

Anti-Virus & Anti-Spyware Is The Bodyguard Of Your System It Is Us Who Rules, Not Malwares

• http://www.tech-faq.com/history-of-computer-viruses.html• http://spamlaws.com/history.html• http://en.wikipedia.org/wiki/Computer_virus#History• http://www.infoplease.com/ipa/A0872842.html

References

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