Work in pairs. Share opinions about

2) boot sector viruses;

3) multipartite viruses;

4) alogic bomb;

5) macro viruses;

6) Trojan horses;

7) computer worms.
Text II

Anti-Virus Software and Other Preventative Countermeasures
EXERCISEEXERCISE 1

Read and translate the text using the list of words and word combinations after the text.

There are two common methods to detect viruses. The first, and by far the most common method of virus detection is using a list of virus signature definitions. The second method is to use a heuristic algorithm to find viruses based on common behaviors. This method has the ability to detect viruses that anti-virus security firms have yet to create a signature for.

Many users install anti-virus software that can detect and eliminate known viruses after the computer downloads or runs the executable. They work by examining the content heuristics of the computer's memory (its RAM, and boot sectors) and the files stored on fixed or removable drives (hard drives, floppy drives), and comparing those files against a database of known virus "signatures". Some anti-virus programs are able to scan opened files in addition to sent and received emails 'on the fly' in a similar manner. This practice is known as "on-access scanning." Anti-virus software does not change the underlying capability of host software to transmit viruses. There have been attempts to do this but adoption of such anti-virus solutions can void the warranty for the host software. Users must therefore update their software regularly to patch security holes. Anti-virus software also needs to be regularly updated in order to gain knowledge about the latest threats.

One may also prevent the damage done by viruses by making regular backups of data (and the Operating Systems) on different media, that are either kept unconnected to the system (most of the time), read-only or not accessible for other reasons, such as using different file systems. This way, if data is lost through a virus, one can start again using the backup (which should preferably be recent). If a backup session on optical media like CD and DVD is closed, it becomes read-only and can no longer be affected by a virus. Likewise, an operating system on a live CD can be used to start the computer if the installed Operating Systems become unusable. Another method is to use different operating systems on different file systems. A virus is not likely to affect both. Data backups can also be put on different file systems. For example, Linux requires specific software to write to NTFS partitions, so if one does not install such software and uses a separate installation of MS Windows to make the backups on an NTFS partition (and preferably only for that reason), the backup should remain safe from any Linux viruses. Likewise, MS Windows can not read file systems like EXT3, so if one normally uses MS Windows, the backups can be made on an EXT3 partition using a Linux installation.

Once a computer has been compromised by a virus, it is usually unsafe to continue using the same computer without completely reinstalling the operating system. However, there are a number of recovery options that exist after a computer has a virus. These actions depend on severity of the type of virus.
EXERCISEEXERCISE 2