Trojans
Unlike viruses spreading on their own, a Trojan horse is a program distributed by people. This program has some other names, namely Trojan program, Trojan horse etc.
Such interesting name the program owes to its principle resembling the Trojan horse from the ancient legend about the fall of Troy. A seemingly innocuous wooden horse was filled with enemy warriors who secretly opened the city gate and let the invaders in at night. A Trojan program also masks as a useful application provoking users to install them to the computer.
A Trojan horse is considered to be one of the simplest malicious programs. Its complexity depends entirely on the disguise means it uses and the tasks it has.
How does a Trojan mask?
A Trojan usually masquerades as an innocuous and helpful program impelling users to install it on their computer. It can also be a nice image or a file. A Trojan can also use ports opened by other applications to mask itself.
Usually a Trojan program consists of 2 parts: a Server and a Client. However, there might be some exceptions like, say, Trojans fulfilling some scheduled tasks (for example, data theft) without any interference. As to the Trojan server Client then in this case a user is helping the fraudster even being unaware of that. When the s Trojan server part detects an access to the Internet it informs the fraudster about the IP address of the infected computer as well as a port for penetrating into the system.
The swindler should remain anonymous, that's why the Trojan doesn't use direct messaging. It resorts to methods allowing the Trojan to launch automatically as a system part when the computer starts.
Here are some examples of Trojan horses:
- Alpha Cleaner
- NetBus
- Pinch
- SpyShredder
- Trojan.Genome.BUY
- Zlob
- CyberGate
2 common ways of Trojan spreading:
- Downloading to user computer performed by fraudsters
- User's downloading a Trojan masquerading as a safe program
Sometimes Trojans are used just as a part of hacker attack at computers and recourses. All Trojan principles are studied thoroughly and these programs can be detected and removed with the help of anti-virus or anti-spyware programs as any other malware.