There has been in the past.
Which exact Mac do you have?
So we know more about it...
At the Apple Icon at top left>About this Mac, then click on More Info, then click on Hardware> and report this upto but not including the Serial#...
Model Name: iMac
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 6 GB
Bus Speed: 800 MHz
Boot ROM Version: IM71.007A.B03
SMC Version (system): 1.21f4
Flashback - Detect and remove the uprising Mac OS X Trojan...
In order to avoid detection, the installer will first look for the presence of some antivirus tools and other utilities that might be present on a power user's system, which according to F-Secure include the following:
If these tools are found, then the malware deletes itself in an attempt to prevent detection by those who have the means and capability to do so. Many malware programs use this behavior, as was seen in others such as the Tsunami malware bot.
The most current flashback removal instructions are F-Secure's Trojan-Downloader:OSX/Flashback.K.
Do you use any "Social" sites, I think some can use your iSight, forget which ones.
I vaguely remember some browsers having a setting or maybe not.
I have never seen reports of a trojan/virus that does what you describe.
• Restart your Mac and see if the problem remains.
• Some apps, including iChat, Apple Remote Desktop, Finder's Screen Sharing, and some third party software can allow others to remotely operate your Mac if they are configured to do so. However, unless you have given someone access, whether by choice or by failing to keep your Mac secure, it is unlikely that anyone else is controlling your iSight.
• You can check your Mac's Activity Monitor utility to see whether any of the apps you have that can use iSight are running when your light comes on. If not, consider the suggestions below. If you do find any third-party apps that you do not want in the list, you can either force quit the app from Activity Monitor or follow the developer's instructions for how to uninstall the application(s).
• You can check your > System Preferences > Users & Groups > Login Items to see whether anything that could use your iSight is starting automatically whenever you login. If so, you can delete the app from the Login Items list.
• If your problem persists, try resetting the SMC as suggested inhttp://support.apple.com/kb/HT2090
• If all else fails, ask your Apple Authorized Service Provider to check your iMac to be sure it is working properly.
I noticed a couple times that the green light has been coming on for my webcam on my iMac. Are there any known trojans/viruses that can do this?
Is there a way to determine if this is indeed ocurring?
Google is capable of activating that.
Removal/prevention of Google cookies:
In the past there was also this issue
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Lion 10.7.3)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images." No, Seriously