Learn 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.