Some of you may remember the virus wallpaper calendars that we published in previous years, listing a selection of significant events in the history of the IT security industry.

Well, we're posting new versions for 2013.

April's wallpaper is here.

clickable!

But be sure to check our calendar page each month as we'll be adding new wallpapers as we go through the year.

We hope they'll be an interesting background for your desktop, as well as highlighting key security events from the past.

There are just 11 days to go until the opening ceremony of the Summer Olympic Games in London. With the games fast approaching, now's a good time for us to issue a gentle reminder about security.

I'm not thinking here about the security of the games themselves. It's possible, of course, that someone might try to disrupt the systems used to support the games - for example, defacing web sites, tampering with scoreboards, or planting malware on official games web sites. But the UK government has put in place a team to try to minimise the risk of direct attacks on London 2012 systems.

But I'd like to highlight two possible dangers that might affect visitors to the games.

First, there's the risk of being tricked into visiting a fraudulent web site that, at first glance, seems to be a legitimate site, e.g. 'www.london2o12.com'. It's possible that scammers might try and cash-in on the last-minute scramble for tickets. This could be done to sell bogus tickets, or simply to trick people into entering personal information. And phishers don't just use e-mail to drive people to such sites. These days, cybercriminals are just as likely to use instant messaging, or messages in social networks.

Second, there's the risk associated with accessing unsecured wi-fi networks. In an 'always-on' world, wi-fi offers a way of staying connected; and you can find a wi-fi hot-spot nearly everywhere you go now. But if it's an unknown, untrusted wi-fi network, it's possible for someone to intercept the data you transmit. So if you're using a laptop or tablet, make sure you have a secure connection by always using 'https'; and use a unique, complex password for every online account (i.e. one that mixes letters, numbers and symbols and is more than eight characters). If you're using a smartphone, don't use an untrusted wi-fi network for any online transaction where you need to type in confidential data - this includes banking, shopping and social networking. And if you have to use public wi-fi (for example, for work), it's best to use VPN functionality, whichever operating system you use - Windows, Mac OS, Android or iOS.

So if you're looking to buy tickets for the games, or just planning to be in London this summer, be vigilant and stay safe.

* Wenlock and Mandeville are the official mascots of the London 2012 Summer Olympics.

As some of you may remember, during 2011 we published a malware calendar wallpaper for each month of the year.

We're doing so again this year, with updated information from 2011. However, we've decided to take a slightly different approach this year and publish all 12 wallpapers in one place. You can find them all here.

We hope you like this year's designs and find the data interesting.

Here's the latest of our malware calendar wallpapers.

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Christmas brings many more people online since the Internet provides a quick and convenient way to buy Christmas gifts. This makes it the perfect time for cybercriminals to cash-in on online activity. So it's also a good time for a reminder about the basic things you can do to reduce the risk of cybercriminals spoiling your Christmas.

1. Install Internet security software and keep it updated.
2. Keep Windows and other applications up-to-date.
3. Backup your data regularly to a CD, DVD, or external USB drive.
4. Don’t respond to email messages if you don’t know the sender.
5. Don’t click on email attachments if you don’t know the sender.
6. Don’t click on links in email or IM (instant messaging) messages. Type the address directly into your web browser.
7. Don’t give out personal information in response to an email or other message, even if it looks official.
8. Only shop, bank or socialise on secure sites. Make sure the URL starts with ‘https://’.
9. Use a different password for each web site or service you use. Don’t recycle them (e.g. ‘jackie1’, ‘jackie2’). Don’t make them easy to guess (e.g. mum’s name, pet’s name). Don’t tell anyone your passwords.

Here's the latest of our malware calendar wallpapers.

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This month's calendar includes a fairly typical mix of cybercrime references. However, I'd like to highlight one in particular - the arrest of a Dutch teenager for stealing furniture from the Habbo Hotel virtual world.

To some people, the idea of having a virtual life seems strange. It may seem even stranger for the police to take an interest in the theft of something that's not real. There are, of course, reasons why they would. For one thing, the virtual theft was carried out by stealing the login credentials of members of Habbo Hotel - essentially a real-world phishing scam like any other. For another, the theft and sale of virtual property can be as lucrative as any other type of cybercrime: in this case, the stolen goods had a real-world price-tag of more than €4,000.

This case underlines the fact that *any* kind of online transaction, if it can be used to make money illegally, if of interest to cybercriminals. So we all need to remain vigilant and take care to safeguard all our online activities.

Here's the latest of our malware calendar wallpapers.

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This month's wallpaper highlights the worldwide nature of cybercrime.

Here's the latest of our malware calendar wallpapers.

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This month marks the anniversary of the arrest of the alleged author of the CIH virus (also known as Chernobyl). This virus was designed to erase the flash BIOS of PCs running Windows 9x, making the machine unbootable - something that was particularly nasty on notebooks, where hardware components like flash memory are built into the motherboard. CIH also had another payload - to overwrite the hard disk with garbage.

This virus was responsible for damage to a large number of computers in South Korea in 2000, three years after its first appearance.

Today the threat landscape is dominated by malware-for-profit, in contrast to the cyber-vandalism of the 1990s. However, CIH provides a reminder that even cyber-vandalism could have a serious financial impact on its victims.

Here's our malware wallpaper for August, highlighting some notable malware-related events from the past.

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Here's the latest of our malware wallpaper calendars.

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As usual, we’ve highlighted some of the notable malware-related events from years gone by.

Here's the latest of our malware wallpaper calendars.

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This month marks the anniversary of the appearance of Cabir, the first malware for mobile phones. This worm - a proof-of-concept worm created by 'Vallez', a member of the virus writing group 29A - was designed to infect devices running the Symbian operating system and to spread using Bluetooth.

Mobile malware has come a long way since then.

• There are now thousands of mobile threats.
• Mobile malware is no longer proof-of-concept.
• Like PC-based malware, most of today's threats are designed to steal money.
• There are threats targeting most mobile operating systems. But the majority are cross-platform, Java-based threats.

On top of this, the use of smartphones has increased massively. And we're all doing so much more with them - at home, at work, or both. As a result, they hold so much more confidential data; and the risk of data leakage from lost or stolen handsets is far greater than at any time in the past.

We all need to be very clear: that's a computer in our pockets or bags - not just a telephone!