Virus and their identity

Posted by prateek on December 19, 2011

virus

Virus is a term usually used for any type of Mal ware, Spy ware or Ad ware.A virus can multiply itself without the user knowing it.It makes copies of itself and attaches itself to executable programs with extensions such as .exe, .sys, .bat,etc.

Viruses are of two types:

Boot Sector/Partition Table Viruses:Boot Sector viruses infect the Boot Sector of the disk.A Boot Sector of a disk is the place where the instructions of booting the computer resides.These Viruses replace the bootstrap code in the boot sectors.It replaces the boot code with its own code for either the DOS boot sector or the Master Boot Record (MBR). The MBR is a small program run every time your computer starts.It controls the boot sequence and determines which partition the computer boots from. The MBR generally exists on the first sector of the hard disk. The Boot Sector Virus is extremely dangerous because every time the computer starts up, MBR executes.So from residing into the primary memory, it can spread wide to all the disks that the system reads.

File Infecting Virus:File infecting virus attaches itself to executable files with extensions like .exe, .sys ,etc.Whenever the infected file is executed the virus stays in the main memory even after the execution of file is over.Then it attaches itself to other programs executed thereafter.Hence, it keeps on attaching itself to other files and spreads.It keeps on infecting in the similar manner.As it spreads, it slows down the computer speed by capturing the primary memory.

Effects Of Viruses

It Slows down the system and may lead to computer crash.
It can delete,change,edit or create files and directories.
It makes copies of itself,therefore reducing the storage memory.
It can result in system hang ups.
It can spread to other computers on your network or by means of Secondary Storage Device (SSD).
It can stop system from booting and working as usually it works.
It cannot infect hardware but affect their performance.