Malware, trojans and threats

Most PCs are now connected to the Internet and networks, making easier the spread of malicious software (malware), which includes trojans (also known as trojan horses), viruses, worms, spyware, adware, rootkits and other malicious or unwanted programs.

Like spyware and adware, trojans can get onto your computer in a number of ways, including from a web browser, via e-mail, or in a bundle with other software downloaded from the Internet.  You may also inadvertently transfer malware via a USB flash drive or other portable media.  It is possible that you could be forced to reformat your USB flash drive or other portable device in order to eliminate the infection and avoid transferring it to other machines.  (You don’t want to be the one who infected your network at work because you were bringing in some music to listen to.

Unlike viruses or worms, trojans do not replicate themselves but they can be just as destructive. On the surface, trojans appear benign and harmless, but once the infected code is run, trojans kick in and perform malicious functions to harm the computer system without the user’s knowledge.

For example, waterfalls.scr is a waterfall screen saver as originally claimed by the author, but it can be associated with malware and become a trojan to unload hidden programs and allow unauthorized access to the user’s PC.

Some typical examples of threats by trojans are as follows:

  • Erase, overwrite or corrupt data on a computer
  • Help to spread other malware such as viruses (by a dropper trojan)
  • Deactivate or interfere with anti-virus and firewall programs
  • Allow remote access to your computer (by a remote access trojan)
  • Upload and download files without your knowledge
  • Gather e-mail addresses and use them for spam
  • Log keystrokes to steal information such as passwords and credit card numbers
  • Copy fake links to false websites, display porno sites, play sounds/videos, display images
  • Slow down, restart or shut down your computer
  • Re-install themselves after being disabled
  • Disable the task manager
  • Disable the control panel

To minimise the threats, most PC users will need an effective anti-malware program to remove trojans along with other malware.

Anti-malware and anti-trojan programs

As more computer security developers are extending their product capabilities to address more than one type of malware, the boundary between different types of anti-malware programs is no more a clear cut and has become blurred.

For example, an anti-virus program such as AVG Anti-Virus covers not only viruses, but offers protection against spyware, adware and others. An anti-spyware program such as SuperAntiSpyware not only detects spyware, but removes trojans, rootkits and other threats. Likewise an anti-trojan program can offer to remove viruses, spyware and other types of malware.

More appropriately, these security products are to be classified as anti-malware programs rather than to be grouped by the name of the products.

In this respect, anti-malware products which are designed to detect and remove trojans more effectively than the others will be reviewed in this category.

How many anti-malware programs need to install?

Do you still need an anti-virus program plus an anti-spyware program and an anti-trojan scanner?
“For the majority of average users the answer is no. A single competent broad spectrum anti-malware product is enough.”
“Of course, not everyone is an average user. Users who engage in high risk activities, like sourcing their software from P2P services, should load up their PC with all the protection they can get. Similarly, there are users for whom the best possible protection is paramount, regardless of cost or performance implications. Finally, users of freeware scanners who cannot afford [or unwilling to pay for] a premium product may be well advised to use more than one signature-based scanner.”
– excerpted from Gizmo Richards’ Support Alert Newsletter Issue 156 April 2008.

Disclaimer

Despite their ratings in this review, some anti-malware programs in certain cases are able to detect more malware than the others depending on their designs, online databases and the infections on computers.

Discussion
a-squared Freea-squared Free is a good choice to scan and remove malware, especially trojans, from your PC. It removes reliably the trojans containing backdoors, keyloggers, dialers and other destructive pests which make it dangerous to surf the web.

Other than trojans, it also can be used to recognize and remove spyware, adware, tracking cookies, worms, viruses and other malware from your PC.

Designed for ease of use, this program combines a-squared Anti-Spyware and the Ikarus Anti-Virus engine in the latest version to cut down on unnecessary double detection routines for one and the same malware.

Features such as quarantine, online updates and heuristic scan for unknown malware are included. As disclosed by a-squared Free, its malware database consists of more than 500,000 malware signatures.

However, this free program does not provide other features such as background guard, automatic updates and scheduled scans.
ThreatFireIf you prefer background guard, PC Tools ThreatFire is a good choice. It provides proactive defense against both known and unknown threats by trojans as well as viruses, worms, spyware, rootkits and other malware.

ThreatFire provides real-time behavior-based malware protection against new or unknown threats without scanning, but running constantly in the background, light on system resources.

ThreatFire automatically quarantines known and unknown threats detected for your protection. After quarantining, you can choose to permanently delete the threats from your system.

The program interface shows you a world map of prevalent threats, either trojans, worms, viruses, or other malware. Further, ThreatFire provides ThreatExpert Reports on the latest 200 findings of threats, more often with more than 30% of them related to trojans.

ThreatFire comes with a feature which allows you to help identify new threats and provide feedback to its Secure Community while you receive automatic updates from them. If you opt out of the Community, automatic updates will not be supported.
Malwarebytes' Anti-MalwareMalwarebytes’ Anti-Malware is another alternative which can be used to scan and remove trojans, along with other malware such as viruses, worms, rootkits, dialers and spyware.

MalwareNET, which is Malwarebytes’ online database, revealed that nearly 20% of the total objects detected by Anti-Malware were related to trojans.

Other features of this program include multiple-drive scanning, quick scanning, ignore list, quarantine to hold threats and restore them, context menu integration to scan files on demand, extra utilities to help remove malware manually, and settings to enhance performance of the program. It works together with other anti-malware utilities as well.  This program has been proven to work very well in removing trojans from an infected system.

However, real-time protection and scheduler are only available to the pay version.
SUPERAntiSpywareSUPERAntiSpyware is worth a try as well. In addition to its focus on detecting and removing spyware infections, this program deals with trojans and other types of threats such as dialers, keyloggers, worms, rootkits, etc.

It supports a quick scan, complete system scan or custom scan with trust items and exclude folders. It also provides an option to check for latest definition updates before scanning to protect you from the threats. On its Threat Research, some typical threats by about 100 trojans are listed here, while the same by about 150 spyware items and other malware items are listed as well.

Among other features, it includes Hi-Jack Protection to prevent other application, except for Task Manager, from terminating the program.

On the down side, the free version of this program does not support real-time blocking, scheduled scanning and some other features.
Other Related Products
These are a number of other free trojan scanners and removers which were brought up in comments here or noted from other sources. As they are not rated in this review, I am listing them here with brief descriptions and links to their sites for ease of reference.
  • Rising PC Doctor comes with a scanner for trojans and spyware, and an option to enable automatic protection such as Trojan Interceptor, Trojan Download Blocker along with some other protections. Other tools such as start up control, process manager, service manager, file shredder, etc., are also included.
  • SDFix is a free trojan removal program written by AndyManchesta to remove trojans along with other malware such as worms, rootkits and others. It requires rebooting the system into safe mode to run the program.
  • Trojan Killer is a malware removal application to remove various types of malicious or unwanted programs such as hidden dialers, adware, spyware, etc. Dangerous items are highlighted in red after scanning and can be removed with a right click. Current database has relatively fewer signatures as compared to a-squared Free.
  • Comodo BOClean Anti-Malware features automatic detection of trojans and other malware in the background with daily database updates. It covers approximately 70,000 trojans in the current database as shown in the list produced by the program with a click on the “Covered Trojans” button

http://www.securitydirectory.asia/articles/best-free-trojan-scanner-trojan-remover-22.html