I have a 4 yr. old iMac. I recently got a trojan on it that sent out emails to my address book. I got Norton Internet Security for Mac, and now my Mac is running slow, with way too many spinning beach balls of death. Was it a mistake to install Norton?

Yes, a big mistake. You did not likely have a trojan. Just an email scammer.

Helpful Links Regarding Flashback Trojan and Virus Protection

An excellent link to read is Tom Reed's Mac Malware Guide.

Also, visit The XLab FAQs and read the FAQ on malware.

A link to a great User Tip about the trojan: Flashback Trojan User Tip.

To check for the trojan: Anti Flashback Trojan 2.0.4.

A Google search can reveal a variety of alternatives on how the remove the trojan should your computer get infected. This can get you started. Or the preferred method is to use Apple's protection tool: Flashback Malware Removal Tool 1.0.

Or, open Software Update. If you do not have the Apple protection software installed it will download and install it via Software Update. If no update appears that means you either already have it installed or it isn't needed for your system. The software is only available for Leopard, Snow Leopard, and Lion versions of OS X.

Also see Apple's article About Flashback malware.

For general anti-virus protection I only recommend using ClamXav.

You need to upgrade OS X to avoid any earlier infections. Backdoor.Cycbot is a Windows trojan.

yankeecat wrote:

... The name of it was Backdoor.Cycbot.

What is that?

Here you go:

http://www.microsoft.com/security/portal/Threat/Encyclopedia/Entry.aspx?name=Bac kdoor%3AWin32%2FCycbot.B

When executed, Backdoor:Win32/Cycbot.B copies itself to c:\documents and settings\administrator\application data\microsoft\svchost.exe.

The malware modifies the following registry entries to ensure that its copy executes at each Windows start:

To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
or subkey: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Adds value: "svchost"
With data: "c:\documents and settings\administrator\application data\microsoft\svchost.exe"

The malware creates the following files on an affected computer:

• c:\documents and settings\administrator\application data\microsoft\stor.cfg
• c:\documents and settings\administrator\application data\microsoft\windows\shell.exe
• c:\documents and settings\administrator\local settings\temp\dwm.exe

These files store configuration and logging information for the malware.

When you find the Registry entries on your C: drive let me know.