A computer will get too slow after being infected by a Trojan. Undesirable web pages open by themself, CD ROM sound get noisy and sometime open and close automatically, inverted images and error messages are the sign of Trojans. Sometime it may eat your RAM and hard drive if certain cautions and measures are not taken. In easy words Trojans are Computer Program that secretly send your computer Data to a Remote PC. All activities on your computer including Paypal and credit card or any type of credentials you use in your PC can secretly fly to the host computer. A trojan is installed by keylogger.exe or server.exe or many other names. The best known Trojans are Back Orfice, and Netbus Trojans. Another Type of Trojan are Data sending Trojans that obtains Credit card information as well as Chat log and address list .Google ads can be used for such purposes. If you click on ads, they will not only open secure or insecure website and who knows what is written as Program on the web page.
Many people receive Trojans when they download anything from website or open an attachment from email.
Hackers, who use data sending techniques, use free email services to receive information from victim machines. Trojans work like a bomb; they wait in the system and start spying or other dangerous functions when activated. Purpose of dangerous Trojans are to destroy important system related file that can corrupt or disable your operating system to use anymore.
It can also be designed as a denial of service attacks, if a large number of users are connected to some machine or website than its internet bandwidth starts to decrease after this attack and cause shutdown of certain website or machine that can’t be useful anymore to users.
Proxy Trojans turn your computer to proxy server. Hacker use victim’s system to steal data, credit card info and all illegal activities. Even victim’s own information and his network’s all information goes to hacker machine and then use victim PC for all illegal activities and in the end Victim’s IP Address and whole network (may be Victim’s company) can be traced back by foot printing methodologies.
It can be removed by several software but in several cases it doesn’t help. However initial levels of rats can be caught by these software.
Zero popup Trojans:
Many a times, while downloading a file, users are urged to download popup blockers and other software which can be a front for Trojans. Using these software from unsecure links can be a reason of allowing Trojans into your system.
Injecting Trojans on Remote PC :
Outside the network it’s not so easy to inject on remote PC , However you can send virus program or .exe file by attachment in some email , inside email their might be some images, some links that on click can download or install or run on the target PC. Search any RATS on Google better to purchase good one rather than to use free version or if you are good programmer you can write your own shell or dangerous Virus depending upon your programming skills but be aware that these Trojans can damage your PC too because obviously these Trojans will send Important data from victim computer to your PC, these data can bind to your PC
Some rats are cybergate Rat , winVNC , downtroj, Nuclear rat Trojan, poison IVY etc. It’s better to write your computer program at least you will be familiar to the danger zone of these Trojans.