Trojan Horse

Description
A Trojan Horse is a program that uses malicious code masqueraded as a trusted applications. The malicious code can be injected on benign applications, masqueraded in e-mails links or sometimes hidden in JavaScript pages to make furtive attacks against vulnerable internet Browsers.

Other details can be found on Man-in-the-browser attack.

The 7 main types of Trojan Horse

1.Remote Access Trojan (RAT)

Designed to provide the attacker full control of the infected machine. Trojan horse usually masqueraded as a utility.

2.Data Sending Trojan

Trojan horse that uses keylogger technology to capture sensitive data like passwords, credit card and banking information, IM messages, and send back to attacker.

3.Destructive Trojan

Trojan horse designed to destroy data stored on victim’s computer.

4.Proxy Trojan

Trojan horse that uses the victim´s computer as a proxy server, providing attacker opportunity to execute illicit acts from the infected computer, like banking fraud, and even malicious attacks over the internet.

5.FTP Trojan

This type of Trojan horse uses the port 21 to enable the attackers to connect to the victim´s computer using File Transfer Protocol.

6.Security software disabler Trojan

The Trojan horse is designed to disable security software like firewall and antivirus, enabling the attacker to use many invasion techniques to invade the victim´s computer, and even to infect more the computer.

7.Denial-of-Service attack Trojan

Trojan horse designed to give the attacker opportunity to realize Denial-of-Service attacks from victim´s computer.

Symptoms

A list of common symptoms is described in this section.

•Wallpaper and other background settings auto changing

•Mouse pointer disappear

•Programs auto loading and unloading

•Strange windows warnings, messages and question box, and options being displayed constantly

•e-mail client auto sending messages to all user´s contacts list

•Windows auto closing

•System auto rebooting

•Internet accounts information changing

•High internet bandwidth being used without user action

•Computer´s high resources consumption (computer slows down)

•Ctrl + Alt + Del stops working

Risk Factor
High

A Trojan horse can break througt all the security polices in a network, because a attacker can get access to a WorkStation that can have network credentials stored in. With this credentials a attacker can compromise all the network.

Likelihood of exploitation
Medium to High

Examples
A Javascript Trojan Horse example can be found on: http://www.attacklabs.com/download/sniffer.rar.

An iframe pointing to a javascript which downloads malware: http://isc.sans.org/diary.html?storyid=2923&dshield=4c501ba0d99f5168ce114d3a3feab567

External References

 * [| Ajax Sniffer]


 * [| Trojan Infection Symptoms]


 * [| The Difference Between a Virus, Worm and Trojan Horse]

Related Threats

 * Category:Client-side Attacks

Related Attacks

 * Spyware
 * Phishing

Related Vulnerabilities
TBD

Related Countermeasures
TBD