Hi Cornelia,

A Trojan Horse is a type of malware that pretends to be something useful, helpful, or fun while actually causing harm or stealing data. Trojans are often silently downloading other malware (e.g. spyware, adware, ransomware) on an infected device as well. One of the most dangerous Trojans is Zeus.

Trojan viruses often are spread via an infected email attachment or a download that hides in free games, applications, movies or greeting cards. Your computer will often slow down because of the burden on the processor. The best way to identify if you have been infected is to use a Trojan scanner, found in any Trojan removal software.

It's best to use a trojan remover that can detect and remove any Trojans on your device. The best, free Trojan remover is included in Avast Free Antivirus. When removing Trojans manually, be sure to remove any programs from your computer that are affiliated with the Trojan.

• Avoid opening unknown files attached to email. These have extensions such as .exe, .vbs, and .bat.
• Maintain up-to-date antivirus protection, preferrably with a firewall.

Protect yourself against Trojan horse viruses

There is no better way to recognize, remove and prevent Trojan horse viruses than to use an antivirus with an anti-trojan component, the best of which is provided by Avast.

Knowing whether your phone has been infected can get tricky, but certain Android virus symptoms stick out like a sore thumb. Here’s what you should look out for…

• Apps that crash...a lot — Some apps tend to crash from time to time. However, if you find multiple apps crashing far too frequently, you might be dealing with an Android phone virus.
• Increased data usage for no apparent reason — Finding your data limit has dropped far more than expected after bingeing on a GOT season is understandable. But what if the same happened after your phone has been just sitting in your pocket the whole day? Might be time for a checkup.
• Ads keep popping up — Those annoying ads can be blocked easily with browsers like Opera. But if they start popping up when there are no apps running, then the ugly truth may be that you have an adware infection.
• Battery drains in no time at all — Since most mobile viruses are not optimized, they tend to drain your battery faster than most other apps.
• Your phone bill is through the roof — Similar to high data usage, a sudden, unexplainable increase on your phone bill is a perfect Android virus warning.
• Unfamiliar apps — Many of us do not usually bother running a check to see if that cool new app is legit or not. Such an oversight can prove costly as you might inadvertently give a fake app the keys to your phone kingdom

So, your worst fears have been confirmed, and all signs point to a virus infection. Your phone isn’t doomed just yet! Here are some methods that will help you rid it of that pesky pest in no time.

Run a trusted Antivirus Scan

Hop on to Google Play and download an antivirus application. But do your homework first. Keep in mind that antivirus apps are a dime a dozen, and there might be virus-ridden malware applications hiding inside them. Only install apps from reputed developers, and if you ever have even an inkling of a doubt the app might be a fake, Google to see if it is.
Also look at third-party labs like AV-TEST and AV-Comparatives. These organizations independently test antivirus apps and publicly post the results. (The free Avast Mobile Security for Android always earns high marks.)

I hope this helps.

Regards,
Lokesh