A computer worm refers to a self-replicating computer program. It relies on computer network to send copies of itself to other computers on the network in an automatic manner. Worms are known to exploit a zero-day vulnerability that allows them to execute their copies within the same network (Effects of Malware Infections: Avoid the Dangers of Malware Programs ). There are several types of worms these are: The internet Relay Chat worms that exploit the Internet Relay Chat (IRS) unlike the Instant messenger worm that exploit the IM channel. The web or internet worm spreads via user access to a web page, file transfer protocol or by use of other internet sources. We also have the file-sharing (Peer-to-peer) worm that copies itself into a shared folder, it then use its peer-to-peer mechanism to make its existence known with the hope that a user will download it. As for the flash form these refers to the theoretical worms that spread within seconds upon activation to all vulnerable hosts on the internet.
A Trojan horse is a non-self-replicating type of malware that tends to perform normal beneficial functions for the user though it facilitates unauthorized access to the user’s computer system. Recently Trojan horse is released as payloads by computer worms that give the attackers full control of the victims’ personal computer (Effects of Malware Infections: Avoid the Dangers of Malware Programs ). There are several factors that make Trojans dangerous, first of all Trojans are not visible in the traditional process viewer. including windows and task managers, this coupled with the fact that most virus and Trojan scanners find it difficult detecting the Trojan code. Also the Trojan code is very difficult to unload hence making it hard cleaning it. The most common type of Trojan is the proxy Trojan that once it attacks the victims computer it turns it into a proxy server (Zombie) which then operates on behalf of the remote attacker. This makes it even more difficult tracing the attack to the attacker as the trail often leads to the victim in most cases. A rootkit is a software system that is composed of several of one or more computer programs that are designed to hide the fact that a computer system has been compromised. Usually an attacker