The most common one is supposedly from a friend in distress abroad, requesting urgent financial help. Do not be fooled by this and always telephone your friend (don’t email, as the hijacker could intercept and confirm the request), where you will probably find him sat at home with his feet in front of the fire.
There are two main ways that hackers use to get access to your address book, the first is by sending you a phishing email or virus link to gain access to your computer, advice on how to spot these emails can be seen at http://www.microsoft.com/en-gb/security/online-privacy/phishing-symptoms.aspx. The second method is by capturing your email login details, this usually happens if you create an account on a website, which could be for online shopping or any other site and use your email address and email password as the login details. Many people use the same password for everything to make it easier to remember, but you should avoid using the main email password for anything else, if a hacker gets these two pieces of information they can send anything they like appearing to come from you.
If you are the unfortunate victim of this form of hacking, which you will probably learn about whilst sat at home in front of the fire when a friend calls to check the validity of the email supposedly received from you, your immediate actions should be:
1. Change your email password as soon as possible - your email provider will usually provide an account maintenance website to allow you to do this.
2. Run a full virus scan of your computer(s) to make sure they are not infected, and remove any infection.
3. Only when these steps are completed can you safely email your contacts and warn them of the scam. If you have not completed the clean up first you could end up passing on the infection.
To avoid being a victim yourself always make sure you keep your antivirus software up to date. If you don’t have antivirus software you are very vulnerable and should install straight away. Free basic versions are available from Comodo https://antivirus.comodo.com or AVG (via filehippo) http://www.filehippo.com/download_avg_antivirus_32
Another useful piece of software is Malwarebytes, https://www.malwarebytes.org which will detect and delete many of the invisible nasties which have crept onto your computer. The free version will run a one-off scan of your computer and zap Viruses, Worms, Trojans, Rootkits, Diallers and Spyware. You can run it as often as you like.
Apple users should also be warned – it is a myth that viruses, phishing, and all the other insidious features of the internet don’t affect them - and they too should ensure adequate protection at all times.