VIRUSES
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New and more threatening viruses appear daily. They spread globally because they travel in the form of an executable email message and newsgroup article attachments. On clicking the attachment, the virus automatically infects the computer.
On a network, viruses do not affect OSI/RM Layer 1 and 2 devices. Cables, NICs, bridges, repeaters and hubs are immune to viruses. Viruses usually affect programs running at the Application Layer - Layer 7.
MACROS
Small programs written in macro code for word processing or spreadsheet applications, such as Word or Excel. When the infected file is opted, the macro is executed.
Small programs written in macro code for word processing or spreadsheet applications, such as Word or Excel. When the infected file is opted, the macro is executed.
EXECUTABLE
These attach themselves to executable programs and are activated when the user launches the program.
These attach themselves to executable programs and are activated when the user launches the program.
BOOT SECTOR
These copy themselves to the boot sector of the hard drive, allowing them to be loaded into the memory each time system is started. Once in the memory, it may replcate itself to other drives and may completely erase the drive it accesses.
These copy themselves to the boot sector of the hard drive, allowing them to be loaded into the memory each time system is started. Once in the memory, it may replcate itself to other drives and may completely erase the drive it accesses.
STEALTH
Avoids detection by redirecting hard drive read requests from the virus scanning software or by manipulating director structure information. This causes the virus scanning program to miss the stealth virus in its scanning process, leaving the virus on the system.
Avoids detection by redirecting hard drive read requests from the virus scanning software or by manipulating director structure information. This causes the virus scanning program to miss the stealth virus in its scanning process, leaving the virus on the system.
POLYMORHIC
The most difficult virus to detect. It has programming code enabling it to execute differently each time it is run, and avoids being detected by virus scanning software.
The most difficult virus to detect. It has programming code enabling it to execute differently each time it is run, and avoids being detected by virus scanning software.