Know More About Trojans and Backdoors

A Trojan horse is an unauthorized program contained within a legitimate program. This unauthorized program performs functions unknown (and probably unwanted) by the user.




■It is a legitimate program that has been altered by the placement of unauthorized code within it; this code performs functions unknown (and probably unwanted) by the user.

■Any program that appears to perform a desirable and necessary function but that (because of unauthorized code within it that is unknown to the user) performs functions unknown (and definitely unwanted) by the user.

Working of Trojans

■Attacker gets access to the trojaned system as the system goes online

■By way of the access provided by the trojan attacker can stage attacks of different types.

Various Trojan Types



■Remote Access Trojans

■Password Sending Trojans

■Keyloggers

■Destructive

■Denial Of Service (DoS) Attack Trojans

■Proxy/Wingate Trojans

■FTP Trojans

■Software Detection Killers

Modes of Transmission



■Attachments

■Physical Access

■Browser And E-mail Software Bugs

■NetBIOS (File Sharing)

■Fake Programs

■Un-trusted Sites And Freeware Software

Backdoor Countermeasures



■Most commercial ant-virus products can automatically scan and detect backdoor programs before they can cause damage (Eg. before accessing a floppy, running exe or downloading mail)

■An inexpensive tool called Cleaner (http://www.moosoft.com/cleanet.html) can identify and eradicate 1000 types of backdoor programs and trojans.

■Educate your users not to install applications downloaded from the internet and e-mail attachments.