Directory Virus Directory viruses (also called Cluster Virus/File System Virus) infect the directory of your computer by changing the path that indicates the location of a file. When you execute a program file with an extension .EXE or .COM that has been infected by a virus, you are unknowingly running the virus program, while the original file and program is previously moved by the virus. Once infected, it becomes impossible to locate the original files. Hideout: It is usually located in only one location of the disk, but infects the entire program in the directory. Examples: Dir-2 virus Protection: All you can do is, reinstall all the files from the backup that are infected after formatting the disk. Polymorphic Virus Polymorphic viruses encrypt or encode themselves in a different way (using different algorithms and encryption keys) every time they infect a system. This makes it impossible for antivirus software to find them using string or signature searches (because they are different in each encryption). The virus then goes on to create a large number of copies. Examples: Elkern, Marburg, Satan Bug and Tuareg Protection: Install a high-end antivirus as the normal ones are incapable of detecting this type of virus. Companion Viruses Companion viruses can be considered as a type of file infector virus, like resident or direct action types. They are known as companion viruses because once they get into the system they accompany the other files that already exist. In other words, to carry out their infection routines, companion viruses can wait in memory until a program is run (resident virus), or act immediately by making copies of themselves (direct action virus). Hideout: These generally use the same filename and create a different extension of it. For example: If there is a file Me.exe, the virus creates another file named Me and hides in the new file. When the system calls the filename Me, the file gets executed (as has higher priority than .exe), thus infecting the system. Examples: Stator, Asimov.1539 and Terrax.1069 Protection: Install an antivirus scanner and also download Firewall. FAT Virus The file allocation table (FAT) is the part of a disk used to store all the information about the location of files, available space, unusable space, etc. Hideout: FAT virus attacks the FAT section and may damage crucial information. It can be especially dangerous as it prevents access to certain sections of the disk where important files are stored. Damage caused can result in loss of information from individual files or even entire directories. Examples: Link Virus Protection: Before the virus attacks all the files on the computer, locate all the files that are actually needed on the hard drive, and then delete the ones that are not needed. They may be files created by viruses. Multipartite Virus These viruses spread in multiple ways possible. It may vary in its action depending upon the operating system installed and the presence of certain files. Hideout: In the initial phase, these viruses tend to hide in the memory as the resident viruses do; then they infect the hard disk. Examples: Invader, Flip and Tequila Protection: You need to clean the boot sector and also the disk to get rid of the virus, and then reload all the data in it. However, ensure that the data is clean. Web Scripting Virus Many web pages include complex codes in order to create an interesting and interactive content. This code is often exploited to bring about certain undesirable actions. Hideout: The main sources of web scripting viruses are the web browsers or infected web pages. Examples: JS.Fortnight is a virus that spreads through malicious e-mails. Protection: Install the microsoft tool application that is a default feature in Windows 2000, Windows 7 and Vista. Scan the computer with this application. Worms A worm is a program very similar to a virus; it has the ability to self-replicate and can lead to negative effects on your system. But they can be detected and eliminated by an antivirus software. Hideout: These generally spread through e-mails and networks. They do not infect files or damage them, but they replicate so fast that the entire network may collapse. Examples: PSWBugbear.B, Lovgate.F, Trile.C, Sobig.D, Mapson Protection: Install an updated version of antivirus. Trojans Another unsavory breed of malicious code are Trojans or Trojan horses, which unlike viruses, do not reproduce by infecting other files, nor do they self-replicate like worms. In fact, it is a program which disguises itself as a useful program or application. ▶ Beware of the fact that these viruses copy files in your computer (when their carrier program is executed) that can damage your data, and even delete it. The attacker can also program the trojans in such a manner that the information in your computer is accessible to them. Logic Bombs They are not considered viruses because they do not replicate. They are not even programs in their own right, but rather camouflaged segments of other programs. They are only executed when a certain predefined condition is met. Their objective is to destroy data on the computer once certain conditions have been met. Logic bombs go undetected until launched, the results can be destructive, and your entire data can be deleted! Viruses Affecting Palm OS The initial launch of Palm OS in 1996 and then the stable release in 2007 made way for attackers to write new malicious codes. The viruses known till date that affect this type of OS are: Liberty Crack: It is a Trojan horse that deletes all your files and applications from your PDA. PEMagic: It allegedly deletes the ROM. Phage: It deletes your files. Vapor: It deletes your files. With all said and done, there is no real threat to your PDAs as regards to virus attacks. There is still no evidence showing the amount of damage these viruses can cause. Viruses Affecting Symbian OS Symbian OS also has no proven virus threats. The only virus that is said to affect the smartphones is the Cabir virus. However, this virus runs in the background and drains the battery power. The fact that these viruses spread via Bluetooth has also proven to be a myth. Read more at Buzzle: buzzle/articles/different-types-of-computer-viruses.html
Posted on: Wed, 19 Mar 2014 13:14:42 +0000
Trending Topics
Recently Viewed Topics
© 2015