Computer Virus and other malware

The term computer virus, coined in 1984, is now well known to the general public. The omnipresence of information technology in the workplace and now in the home, the use of the Internet and, more generally, networks (computer, telephone), and the emergence of connected and communicating objects have confronted almost all users, at least once, with the risk of viruses. However, it turns out that in reality, users' knowledge (in the broadest sense of the term) of computer virology still has many gaps, to the point of increasing rather than decreasing the risks. In fact, the term "virus" itself is improperly used to designate a more general class of programs that have nothing to do with viruses: worms, Trojans, logic bombs, decoys... Moreover, viruses are far more complex than they appear. Numerous sub-categories exist, and numerous viral techniques are involved, all implying different risks, which need to be understood in order to protect and combat them effectively.

In 1999, the ILoveYou worm infected over 45 million computers worldwide. In 2003, the Sapphire/Slammer worm infected over 75,000 servers worldwide, in around ten minutes. In 1998, the CIH Chernobyl virus forced thousands of users to replace their motherboards after destroying the BIOS program. The damage caused by this virus is estimated at around 250 million euros in South Korea alone, compared with several billion euros for a computer worm. According to the FBI, the threat posed by BotNets since 2002-2003 concerns one computer in four worldwide, i.e. almost two hundred million machines infected without the owner's knowledge. The Storm Worm attack, in the summer of 2007, hit over 10 million machines worldwide in less than a month. These figures forcefully demonstrate the importance of taking the viral threat seriously. Since then, attacks have multiplied to such an extent that they are no longer systematically reported in the media. It seems to have become a reality that individuals and businesses alike have realized they have to live with. The case of ransomware is one of the most illustrative examples. The recent attack by the Wannacry virus in June 2017, however, has shaken the world out of its torpor: by giving a second birth to certain codes that were thought to belong to the past, it forcefully confirms that mafiosi and other hackers are no longer the only evil actors using computer viruses. In fact, we now have to include governments, which are making ever more frequent use of them not only in their espionage operations, but also in more conventional warfare: the so-called "cyber" dimension, after the land, air and sea components, has become a sad reality.

In this article, we'll introduce computer viruses and worms and consider them in the general context of today's more realistic computer infections....