I think that I may have a computer virus. Can anybody help?

Get an anti-virus program—- AVG free is my recommendation.

Do it now. Yes you are infected, IMO.

This has happened to me several times. You may have the virus if you didn’t stop the download quickly enough. Check your computer programs to see if any strange Anti-virus programs have appeared that you don’t recall downloading yourself, and that are recent (the date this happened).
I recommend Norton.
I had McAfee, and it didn’t catch the virus that really shut down my computer, but Norton always catches the same virus that has infected your computer (and my computer) before it caused any damage.

Google “Comodo” Download the free firewall+anti-virus.

If you don’t know whether or not you have an antivirus program, then find out. If you don’t know how, get someone to help you.
If you are already infected it is too late to install an antivirus program. Since you can’t know at this point whether or not your computer is compromised, you must assume that it is. Therefore you need to find and antivirus program which can run at boot, before your system starts. Your best bet will be a CD that boots into a “live” environment. There are a wide variety of Linux-based CDs of this type, and if you have a verified copy of Windows you can make a Windows-based one. Parted Magic should work, as it comes with the ClamAV antivirus program.
I will leave it to others to recommend specific antivirus products, as I’m not familiar with the field these days.

First off, @koanhead is 120% correct; if you don’t know if it’s infected, assume it is.

As for specific AV programs, here are the detection rates for some popular anti-virus programs according to AV-Comparatives

Avast – 98.4%
Avira – 97.5%
Kaspersky – 97.0%
McAfee – 96.8%
Microsoft Security Essentials – 95.8%
Symantec (Norton) – 95.5%
AVG – 91.4%

I think you can see why the only two I trust that people may even have heard of are Avast! and Avira. And those who trust AVG are bound for the same fate I suffered when I was that naive; the only virus I ever got was with AVG guarding the gates.

Thanks @jerv – I will remember this when next I venture into Windows land.
Also I will stop recommending MSSE in favor of Avast.

My computer is stuggling after either a virus or a bad upgrade from MicroSoft.
My Bit Defender antivirus didn’t catch it.
At the moment, it appears I have lost all pictures and personal documents. Quite the heartbreaker.

You can download microsoft’s free malicious software removal scan run it and when complete and threats removed, select, download, and install a free AV program.
Good free ones include MS Security Essentials, AVG Free. Avast! and others. Some safe sources are cnet and majorgeek

Go into CONTROL PANEL then click on SECURITY CENTER.. Go down to MALWARE PROTECTION and open this drop-down.. Here it will inform you whether or not you have virus protection and (if so) exactly what brand it is.. If you have none then follow koanheads advice then jrev and anartist’s suggestions. Free virus protection is okay for a clean system but if you want realtime protection then you need to spend a few bucks.. Also get two.. One bought that operates automatically and a free one that you can use manually to confirm that all if fine.. I use it this way and feel very protected.

Unless you gave the application root access (I.e. Typed in your username and password for the app to install itself), then your computer is perfectly fine.

@Silence04 not true

Why wouldn’t the first thing you do not be get an antivirus proggy?

@XOIIO
I figured… Well, it’s a mac, man!

@jellyfish3232 Sure, Macs are less affected by viruses because PC’s are set up with a different system, plus businesses and offices all run PC’s, Macs are more for artsy and producing stuff, not paperwork and stuff like that. You should still get an anti virus though, because more are coming out for macs.

@Silence04 Just because the user didn’t explicitly give privs to the process doesn’t mean it didn’t get root by some other method. Root exploits do exist for BSD.

@jellyfish3232 It would have helped a bit if you’d mentioned at the beginning that it was a Mac, but it doesn’t really change anything. As @XOIIO says you still should have antivirus and I say you should still run a scan if for no other reason than to reassure yourself.
Your computer shouldn’t be “automatically downloading” things. Sometimes websites will pop up a fake file download dialog window, but it usually has Windows-style window decorations and doesn’t actually download anything unless you explicitly interact with it. The script could easily adapt the appearance of the window using a technique called “browser sniffing” (most browser UA strings contain OS information), but they should not be able to get your computer to automatically download something (unless it’s an Windows machine running IE and it’s an ActiveX script).
The fact that there was a file on your desktop for you to delete makes me suspicious that something might be very wrong.
What browser were you using at the time? What version OS?

@koanhead

I was using safari. OS version 10.4.11.

yeah there have been JVM exploits (not top level bsd exploits) that would allow root access, however all known exploits of that kind have since been patched. And no known Mac virus has used JVM exploits as an injection method.

It seems silly to run a antivirus software constantly In the background, using up many resources of such an old machine with very little risk of any virus. Keeping a regular back up of data seems like the simplest solution.

@Silence04 You are quite correct, and I’m not asking that @jellyfish3232 run antivirus constantly in the background. However, there is reason to think that an exploit of some type has occurred, and it’s best to try to find out what happened rather than to assume that everything is ok (even if that is the most likely scenario.)

What I’m advocating is a one-time comprehensive scan of the unmounted filesystem from a live environment. Now that I know it’s a Mac I will recommend the use of ClamXav since it’s the only free Mac antivirus I found in a quick search.

@jellyfish3232 You have been keeping regular backups, RIGHT?

@Silence04 The way I see it, if my old 200MHz Pentium with 48MB of RAM could handle a resident AV program, any machine built in this century had more than enough resources to run one without bogging.
As for the risk, I have managed to infect a clean install of Windows within seconds of connecting to the internet without even firing up any applications. If I got one just during there, imagine how much more likely it is for someone who surfs or installs stuff to get infected.

@jerv That’s why I DL an antivirus installer on a PC with antivirus that way I don’t get one while trying to get one.

@koanhead
Well, I’ve been keeping all of the important files on my flash drives. So, yes.
I love my flash drives. I keep them on a necklace and wear them with me.

@jellyfish3232 That’s good! That means in the worst case, you can just reinstall your OS and not lose your important files.
Have you made any progress in determining whether or not your system was compromised?

@XOIIO From what I have read MACs used to be safe but aren’t anymore. In fact windows might be safer since it has been working on improving its security over the years whereas MAC has ignored it.

@raven860 probably true, peoPle have had a long time to develop effective viruses for macs

@koanhead
Yep. I ran a full system scan… I’m clean!

The virus can be downloaded through your IP address automatically. If I were you I would do a complete scan after getting some good virus software.

The only virus I ever had was contracted within seconds of connecting and I didn’t even open up anything like a browser. It was due to an exploit in the Messenger service of WinXP (not to be confused with MSN Messenger, which is something else entirely), and a blind spot in AVG’s coverege.

After a full night of four clean installs and re-infections, I finally figured it out, hacked the Services list and Registry before connecting to the ‘net, and only after disabling a useless part of WinXP that is enabled by default was I able to connect without getting infected within seconds.

The first thing I did after that was find a better anti-virus program :P