Can a computer give a cell phone a virus?

it is certainly possible. A lot of digital picture frames came loaded with a virus right from the factory. I believe some viruses can transfer from one device to another very simply. And it would be worse if you had a phone and a computer running sibling operating systems.

Technically, yes. However, it is unlikely that that virus would actually infect the phone as the operating systems are quite different, so one system or the other would merely become a carrier.

Also, such a virus would have to be coded for a specific operating system combination, so it would only affect, say, Macs hooked to Android phones. As virus writers tend to want to go for the widest spread with the least effort, that also limits things a bit. Linux and Mac OS X are relatively uncommon, so such a combination is unlikely to be worthwhile. And combination involving the Linux OS for PCs would have a very short lifespan, so it would almost have to be Windows-exclusive. You might get around that by coding the virus into a cross-platform document, but it wouldn’t be hard for any competent anti-virus software to check for and block those as well.

As for which phone OS to infect… Android is a bad choice since whenever you install an app, it displays a screen telling you a permissions list detailing what the app can/can’t do. Granted, many people ignore blatant warnings like that, but it does make things more difficult and those that wind up infected really have nobody to blame but themselves. And PalmOS and Blackberry are fairly minor players, so the easiest (and thus, most likely) combo is Windows/iOS 4 to nail iPhone owning Windows users. So that is the combo I would be most wary of.

@jerv unless you’ve jailbroken the iPhone or have opened up your phone for developer testing purposes (you would know this if you did because it’s involved), you won’t be able to install 3rd party software on it without going through the App store.

There have been viruses on jailbroken iPhones, but to the best of my knowledge there has never been one on a non-jailbroken one—that is one (arguably the only) benefit of the walled garden Apple app-store approach. What phone and what kind of computer do you have? I think it’s fairly unlikely that you could get a virus, but it’s certainly not completely impossible.

@gorillapaws Comparing the number and frequency of app crashes and system hangs I had with my iPod Touch versus the number or Force Closes and such I’ve had on my Droid X, I would almost say that viruses are a moot point and disprove the alleged safety of a “walled garden”, but I don’t feel like starting an argument.

I will say that Apple is a bit more open than they were and may have to open up even more to counteract one of the biggest complaints people have about the iPhone vs Android if they want to stop getting outsold the way they have been lately, and that may change things.

What some call “impossible”, others see as “a challenge”... and I mean that in more ways than one. The truth is that there are ways to attack and infect any system, even a non-jailbroken iPhone. Security researchers have proven it possible even now with the current “walled garden”, so I see it as I see it as only a matter of time before someone else finds a way and actually distributes it in the wild, especially given the animosity many have towards Apple. People go after Windows because it’s easy, but they go after Apple out of sheer visceral hatred, and that motivation can make them dangerous, especially to a crowd who considers themselves immune and thus don’t protect themselves. (My Droid X has anti-virus software installed; I may suffer some delusions, but the delusion of safety isn’t one of them.)

For the moment though, you are entirely correct, and that is the reason that I generally (though not always) get my apps from the Android Market while eschewing alternative sources. Too many people get into trouble with their computers by trusting the wrong people and catching more infections than ten low-rent hookers..

In principle any interconnected digital devices are capable of this.

Definitely, Yes! Because a lot of cell phones (especially intelligent ones) installed hundreds of softwares and stored a lot of files. When it’s connected to computer, virus can spread from computer to cellphones.