One of the most commonly asked questions by newcomers to linux is about the need for antivirus.
The majority mailing list opinion is this -
- Linux viruses may be a theoretical possibility, of debatable impact. Practically speaking, there just aren't any you are likely to find. Don't install A/V to protect your Ubuntu system. The possiblity of it doing harm is higher than the possibility of it helping you.
- Windows viruses can be passed along by Linux boxes via email or file shares etc. without affecting the Linux system. If you want to protect your friends using Windows, tell them to use Linux. If that doesn't work, and you still want to help them, you could install A/V to scan your file shares.
Clam AV. is the most popular open source application for anti-virus.
- Commercial products (free of charge and for payment) are available from companies like Grisoft (AVG), Bitdefender and others. Go ahead and Google for your favourite if you are so inclined.
Please note that not requiring an anti-virus product doesn't mean you can ignore all common security issues in Linux. That's just one of a large numbers of nasties that can bite you. It's still very important you keep your system up to date with security patches, only install software from trusted sources, and use common sense on the internet.