To use the victim’s computer as an FTP server for pirated software.To use the victims’ computers for storing archives of illegal materials, such as child pornography.Important company projects, including presentations and work-related papers.Account data such as e-mail passwords, dial-up passwords, and Web service passwords.Credit card information, which can be used for domain registration, as well as for shopping.To steal sensitive information, such as:.Trojans are created for the following reasons: The packets are encapsulated in IP datagrams. It is used to provide error messages to unicast addresses. ICMP (Internet Control Message Protocol) is an integral part of IP, and must be implemented by every IP module. Another example is the Goner worm, detected in December 2001, that deleted antivirus files. An example is the infamous Bugbear virus that installed a trojan on the machines of infected users and disabled popular antivirus and firewall software. After these programs are disabled, the attacker can easily attack the victim’s system. These trojans are designed to disable antivirus software or firewalls. These trojans open port 21, which is used for FTP transfers, allowing the attacker to connect to the victim’s system via FTP. This can lead to legal trouble for the victims, because the victims are responsible for their network or for any attacks launched from it. If the authorities detect illegal activity, the footprints lead to innocent users and not to the attacker.
The attacker has full control over the user’s system and can also launch attacks on other systems from the affected user’s network. Generally, it is used for anonymous Telnet, ICQ, or IRC in order to purchase goods using stolen credit cards, as well as other such illegal activities. This makes the computer accessible to the specified attacker. These trojans convert the user’s computer into a proxy server. The basic idea behind this kind of attack is that if there are more than 150 infected ADSL users on the network and the victim is attacked simultaneously by each user, it will generate heavy traffic that will eat up bandwidth, causing the victim’s access to the Internet to shut down. This type of trojan empowers the attacker to start a distributed denial-of-service (DDoS) attack. They can be activated by the attacker or generated on the basis of a fixed time and date. These trojans are destructive because they can delete core system files such as. The sole purpose of writing this type of trojan is to delete files on the target system. An example of this is the Badtrans.B e-mail virus (released in December 2001) that could log the user’s keystrokes.
The captured data can be sent to the attacker via e-mail, or by connecting to the attacker’s Web site by using a free Web page provider and submitting data via a Web form.
Trojans that install keyloggers can record keystrokes and send them back to the attacker. A keylogger is a piece of software or hardware that records keystrokes or mouse movements. Data-sending trojans can also install a keylogger on the victim’s system. This type of trojan provides attackers with passwords or other confidential data such as credit card numbers and audit sheets. Examples include the Back Orifice and NetBus trojans. Attackers in the same network located behind the firewall can easily access the trojans. The remote access trojan acts as a server, and listens on a port that is not supposed to be available to Internet attackers therefore, if the user is behind a firewall on the network, there is less chance that a remote attacker would be able to connect to the trojan. Remote access trojans provide attackers with full control over the victim’s system, enabling them to remotely access files, private conversations, and accounting data on the victim’s machine. Understand Working Of Trojans Identify The Different Types Of TrojansĪ command shell Trojan is intended to provide a backdoor to the system that you Overt channels are legitimate communication channels used by programs across a system or a network, while covert channels are used to transport data in unintended ways. A Trojan is software that appears to perform a desirable function for the user prior to running or installing it, but instead performs a function, usually without the user’s knowledge, that steals information or otherwise harms the system (or data).