Trojans are not new in the cyber crime world. However, they remain one of the most effective ways of achieving the spread of malicious software thanks to their design. Like the Trojan Horse that infiltrated the City of Troy, Trojan viruses come masquerading as a piece of completely harmless data or programming. Once inside a network a Trojan can start deleting and blocking data, modifying and copying it, as well as disrupting machine or network performance. Unlike a virus – whose purpose is to infect files and then spread itself – Trojans don’t need to spread themselves or corrupt the files they come across as they can cause havoc simply with their presence alone.
The consequences of a Trojan
Thanks to the disguise element of the Trojan, it often enters a user’s computer as a result of something that the user themselves has done. For example, it may appear to be an attachment in an email that promises positive results, useful information or looks like it has come from an official source, such as an employer HR department or a bank. Once the Trojan is opened it has access to everything that happens on the machine it has arrived in and this information can be sent back to a server specified by the Trojan. So, every piece of sensitive information typed into email login or online banking can be collected and stored by the hacker. Trojans can even be used to create ‘zombie’ computers, which hackers then remotely operate to carry out further cyber attacks.
How can you protect yourself?
- Choose your sites carefully. Avoid browsing websites that you know are spammy or which may be full to the brim with adware. If you don’t know that an ad has been created by a trusted source then don’t click on it.
- Maintain up to date systems. It is an ongoing battle for vendors to provide patches in their products for holes that have been exploited by hackers and if you don’t keep systems up to date then you don’t have access to these fixes and you remain vulnerable.
- Use an antivirus software or Trojan remover. These can automatically scan your operating system to make sure that it’s Trojan free.
- Don’t subscribe to anything from an untrusted source. If you’re downloading software then be sure to uncheck the boxes for ‘extra programs’ unless you know what you will get.
- If you think that you have a Trojan then get rid of it before rebooting the machine as the reboot can be the trigger for the Trojan taking over your system.