What does a Trojan virus do to a computer?

happyviolet

I just recently did a scan for the first time in ages (usually had it scheduled once a week, but never scanned for some reason, so had to do it myself), and realised I had a Trojan virus on it. I removed it quickly, and after running another scan just to be on the safe side, my PC is safe.

But what can a Trojan virus do to a computer? I remember I had a dodgy homepage thing when I had to download to get some software for school and it turn out to be a secret virus, but i got rid of all that. So I really don't know how I got this trojan as I did not click on anything that looked dodgy or not right. It freaks me out that it was there so long.

So what can it do and am I safe now? I have a built-in webcam (that i have taped over now) and I hear how hackers can even hack in the cam to spy on you?! I am really freaked out now.

Overheal

Trojan refers to the vector of attack. Trojans disguise themselves as legitimate pieces of software to get on your PC before causing damage. Worms are self replicating viruses, a root kit will latch itself into the basic levels of your OS and supplant normal system files, etc etc

They can all do some amount of harm. A rootkit can lock your machine down and hold it to ransoms (the Garda/FBI child pornography virus), delete your user data, cause advertisements to appear, change system settings or even log keystrokes and transmit your activity and stored information (credit cards, passwords, photos, documents) to a third party. Some viruses add your machine to a botnet for use in DDoS strikes.

In short any given virus can do a wide range of things. Newer hardware is going to support better layers of security though. For instance Intel Core processors (i7 etc) can detect virus execution at a hardware level an kill processes before they have a chance to attack protected levels of memory

Jonny Blaze

Yeah that sort of thing is possible alright, however I would imagine that the vast majority of trojan viruses out there at the moment would be geared toward entering your machine into part of what is known as a botnet.

These are basically large networks of 'zombie' computers who can be controlled by hackers in order to send spam and engage in other malicious activities.

Realistically most hackers would prefer to use your machine for this type of activity, which has the capacity to earn them money, rather than messing about with your webcam or trying to get data from any particular user which is more finnicky, time consuming and labour intensive.

Webcam hacking i would class as more of a 'recreational' hack that few malicious individuals with criminal intent would be bothered with. More like bored american teens..

Keeping a low profile on your machine and sending out spam would be my guess as to what it was up to.

Regardless, after the scan if it all seems clear then you should be grand, assuming you have decent anti malware.

richierichballs

Overheal wrote: »

Trojan refers to the vector of attack. Trojans disguise themselves as legitimate pieces of software to get on your PC before causing damage. Worms are self replicating viruses, a root kit will latch itself into the basic levels of your OS and supplant normal system files, etc etc

They can all do some amount of harm. A rootkit can lock your machine down and hold it to ransoms (the Garda/FBI child pornography virus), delete your user data, cause advertisements to appear, change system settings or even log keystrokes and transmit your activity and stored information (credit cards, passwords, photos, documents) to a third party. Some viruses add your machine to a botnet for use in DDoS strikes.

In short any given virus can do a wide range of things. Newer hardware is going to support better layers of security though. For instance Intel Core processors (i7 etc) can detect virus execution at a hardware level an kill processes before they have a chance to attack protected levels of memory

I actually got this virus on chrome browser on my macbook pro (mid 2010,)
I had it for a few days and didn't really have time to try remove it.

So Saturday came around, I had a big mug of coffee and was ready to sit down and get rid of this thing and it was gone?

The pop up that wouldn't close had disappeared. I uninstalled the chrome browser and ran a full scan and nothing appeared.

Should I do anything next or just take it that it's gone?

Jonny Blaze

It's weird to have even gotten a virus on a mac in 2010 I would have thought!

The general consensus is that most malware is targeted at windows operating systems as they are used by a much larger percentage of the global population (at least up until relatively recently), add that to the fact that chrome only came out at the end of 2008 and it would seem fairly unlikely.

Unfortunately I rarely ever use a mac so I can't really comment but I would imagine you are safe enough, again providing the scans are showing up all clear and you have decent anti-malware.

richierichballs wrote: »

I actually got this virus on chrome browser on my macbook pro (mid 2010,)
I had it for a few days and didn't really have time to try remove it.

So Saturday came around, I had a big mug of coffee and was ready to sit down and get rid of this thing and it was gone?

The pop up that wouldn't close had disappeared. I uninstalled the chrome browser and ran a full scan and nothing appeared.

Should I do anything next or just take it that it's gone?

Fortysumting

Hi

Can anyone advise me on removing a trojan virus. I have tried to get rid of it using free anti-virus software but it obviously is'nt enough. Any advice on free software that would do the trick??

Many thanks

advertsfox

Fortysumting wrote: »

Hi

Can anyone advise me on removing a trojan virus. I have tried to get rid of it using free anti-virus software but it obviously is'nt enough. Any advice on free software that would do the trick??

Many thanks

Run a Webroot trial, installs in 1 second and will scan your PC in 30-60 seconds.

syklops

Not to be the pedantic weasel of the group but there is a dedicated forum for malware removal.

The general consensus is that most malware is targeted at windows operating systems as they are used by a much larger percentage of the global population (at least up until relatively recently),

Apple has been gaining a greater market share in recent years and so yes, there is malware now targeting iOS. Most Mac users don't employ AV software because they have been lulled into a false sense of security.

add that to the fact that chrome only came out at the end of 2008 and it would seem fairly unlikely.

I don't understand what you mean by that. Vulnerabilities are found in both brand new software and older software. The first version of Chrome that came out there was a zero day for a drive by download online within hours.

uncle_sam_ie

Fortysumting wrote: »

Hi

Can anyone advise me on removing a trojan virus. I have tried to get rid of it using free anti-virus software but it obviously is'nt enough. Any advice on free software that would do the trick??

Many thanks

Once you've been compromised they have to keys the kingdom and can do what they want. The only true way of knowing you're free from infection is to wipe it and reinstalling the OS.

Torqay

uncle_sam_ie wrote: »

Once you've been compromised they have to keys the kingdom and can do what they want. The only true way of knowing you're free from infection is to wipe it and reinstalling the OS.

+1

Never ever trust a system once it has been compromised.

Jonny Blaze

I don't understand what you mean by that. Vulnerabilities are found in both brand new software and older software. The first version of Chrome that came out there was a zero day for a drive by download online within hours.

That's true enough alright, I was merely saying that widespread virus infection as opposed to zero day technical security flaws on a new browser would have come as a surprise to me at least.

syklops wrote: »

Apple has been gaining a greater market share in recent years and so yes, there is malware now targeting iOS. Most Mac users don't employ AV software because they have been lulled into a false sense of security.

That's also true, however according to the w3c website the volume of mac operating systems used to access the web in 2010 was only in the range of 6.8 - 7.3%, whereas now it is up to 9.3%.

I'll definitely agree that these statistics aren't bulletproof either however they are a well regarded source of guiding information on the topic.

creep

Keylogger by the sounds of it. If you use the same password as your yahoo mail on any other site then change the passwords

Bog Standard User

trojan virus mostly steal info...

there are many types but the 3 main ones do the following

1. data miners - these steal personal info about u - passwords - social security info - personal info - websites you frequent

2. denial of services - these lock down certain functions on your pc

3. data encrypters - these are the worst - cryptolocker being the worst this slowly encrypts all your files with a 2048bit encryption key and demands you pay a ransom of $300 within 100 days to unlock your files or it deletes the key locking your files forever (if u have a lot of work files back them up regularly onto dvd or use online cloud backup services such as dropbox or google cloud)

Overheal

Torqay wrote: »

+1

Never ever trust a system once it has been compromised.

To what end?

http://gizmodo.com/government-destroys-170k-of-hardware-in-absurd-effort-708412225