How To Explain A Trojan Horse To A Five-year-old

Paul Briault, senior director, solution sales, Security at CA Technologies

“A Trojan Horse is something that you may download on your computer by accident, that does harmful things. It will trick you into thinking that it’s a computer game or a movie so that you open it and then it will start doing horrible things to your computer – it may delete all the pictures from your holiday or try to steal your mum’s bank account password. You won’t know it’s happening because it may not do those bad things straight away – it may wait days or weeks to do them – at a time when you least expect it to happen.”

Scott Tyson, director global sales at Mailprotector

“Imagine your house has a leaky tap in the kitchen and your parents call a plumber to come in and fix it. They don’t know any plumbers, so call a number they found in a brochure that was popped through the letterbox.

“The plumber comes round and starts looking at the tap, but as he does that, he starts asking questions as to how long your mum and dad have lived there, do they work, do they go out a lot, what do they have planned this week, and so on. He then starts looking round the house saying he needs to check all the taps and where the pipes go. All the while, he is not actually a real plumber, but a pretend one – he’s really a robber who is making sure he knows what good stuff you have in the house, how he can get in and when he can break in while you’re all out. His real reason for being there is to steal from you and your family.”

Greg Iddon, security consultant at Sophos

“Think of your computer as a big city, with you the king, and it’s full of money, fun, and wonderful things. People outside want in – it looks like an awesome place! Sadly, there are scoundrels who will get up to no good if they get inside!

“Thankfully your city has gargantuan walls and a single gate where your guards scrutinise the identification of everyone coming in. City engineers work hard to repair any flaws in the walls – this means that those pesky outsiders look for other ways in.

“One day, outside your gates, is a free copy of the latest computer game with choirs of angelic voices enticing you to give it a go. It’s a trap – a Trojan Horse! See, those pesky outsiders have hidden an army of bandits inside (it’s a really big box…pretend it’s the 90s) waiting for you to take it inside to play. But when you do, they’ll burst out, steal your wallet, set fire to the upholstery, and more chaos *shakes fist*.

“This is why we should give our guards scanners and x-ray vision (i.e. antivirus) to ensure those troublemakers get caught red-handed and burned at the stake. Long live the king!”

Mark James, security specialist at IT Security Firm ESET

“A Trojan horse is a computer program that pretends to be one thing on the outside but is actually something else on the inside. It’s like a chocolate egg with broccoli inside, once this Trojan horse has managed to get onto your computer it turns into something nasty with the intention of making bad things happen to your device. These things may include installing a virus or stealing your precious data. Bad software will often use these techniques in an attempt to deceive or lie to you about its true identity. We should always be very careful about what software we install, always check with your parents or guardian before downloading new games or software especially if they are free.”

Mike Westmacott, cyber consultant at Thales UK

“Imagine that you, Susie, have a birthday, and your clever but mean older brother gives you the SINGING ANNA FIGURE FROM FROZEN! All day long may you sing ‘Let it go’ in duet, much to the delight of your parents. Alas though, your mean brother found on the Internet a way of changing the song after it has played a number of times – and so his plan ultimately comes to fruition – and in front of your much anticipatory friends does dear Anna suddenly announce, at full volume, ‘Susie smells of wee’. Repeatedly. The present that initially gave much joy and mirth has suddenly become a thing of fraternal war…”

Mike Spykerman, vice president of product management at OPSWAT

“Imagine someone delivers a big package to your door. Excitedly you take it inside and unwrap it. It is a giant cuddly bear. You decide to wait until your Dad gets home to take it out of the box. In the meantime, you go and play upstairs. While you are out of the room, a person climbs out of the bear, steals all your toys and takes off. You come back later, only to discover that you have been horribly tricked.”

Ian Trump, security lead, LogicNow

“Trojan computer programs are like hide and seek with a surprise! When you hide in a closet and then Mummy or Daddy reaches in for something and you leap out and wave your hands and make a big noise, you scare them. Well, bad people play hide and seek too – with computers.

“They send Mummy or Daddy a file and they click on it. Sometimes the surprise is invisible and now the bad guys are in the computer and maybe they will use the computer for bad things and make Mummy or Daddy upset. You can protect Mummy or Daddy by telling them to never click on email files from people they don’t know. You can help by reminding them to keep their computer up-to-date and have anti-virus.

Andy Green, senior digital content producer at Varonis

“Once upon a time in a far off land, the Greeks were laying siege to Troy in order to get back their beautiful princess. It was not going well. So to get into the castle, the Greeks crammed an entire army into a giant wooden horse, which they gave to the Trojans as a gift. The Trojans loved presents, opened the castle gates, and accepted this magnificent horse. That night the hidden army came out of a secret door in the horse, defeated the surprised Trojans, and took back the princess. Nowadays, Geeks, not Greeks, may be offering free applications on the Internet. However, similar to the horse, the Geeks have crammed evil malware into this software gift. When you launch a Trojan Horse app on your laptop, the bad code is released, and it will steal your credit card numbers and passwords The moral: Beware of Geeks Sharing Free Appware.”

Simon Mullis, security expert at FireEye

“Sarah is new in your class at school, she comes from a long way away and tells some fantastic stories. She seems really nice and is very funny. She tells jokes and shares her sweets with you and she never minds when she is “it” first when you’re playing tag. Mrs. Baxter, your teacher, likes her too because she is very polite and seems to do exactly what she is told. She could be your best friend! However, secretly and without you knowing, Sarah is whispering bad things about you behind your back to your friends and copying your answers to the maths quiz when you’re not looking. She isn’t really a nice friend at all.

“This is what we mean when we say ‘Trojan Horse’. When talking about computers, a Trojan Horse is a programme that pretends to be useful or nice but is actually horrid and does bad things like trying to steal your passwords or take pictures of you with your webcam without you knowing. You have to be careful when you run or install new programs just in case they secretly do bad things.

Tony Anscombe, senior security evangelist, AVG

“Imagine it’s Christmas Day and this year you’ve been really good and asked for a brand new board game. You unwrap one of your presents and see the box of the game you asked for, but when you open the box up it’s full of smelly socks! What a horrible trick! It looked like the game you wanted from the outside, but inside it was not what you wanted at all.
The same thing can happen when you go online – this is called a Trojan Horse. Just like the board game box, the Trojan Horse appears good on the outside, gains your trust and makes you want to open it up – once you’ve opened it, the Trojan Horse can do all sorts of bad things (much worse than a box of smelly socks!) to your computer.”

Kane Hardy, vice president of EMEA at Hexis Cyber Solutions

“A Trojan Horse is the name that we give to a secret message that some unkind grown-ups use to trick other people so that they can break into their computers.

“It works like this; the naughty grown-ups might send a message to someone’s computer that shows a picture of something very nice, like a new toy or delicious sweets. Then, if the person clicks on the nice picture of the toy or the sweets, the naughty people can break their computer or take things from it that they shouldn’t.

“This is a nasty plan and the message that the naughty people send is called a Trojan Horse.”

Richard Brown, director of EMEA Channels & Alliances at Arbor Networks

“Trojan horses are like villains wearing masks, hiding themselves as something fun like a game and when you play them they cause damage to your computer or collect your personal information for naughty purposes. The next step up is a more evil version where a villain goes to your house dressed as your best friend to trick you, so you don’t realise they are stealing your stuff.”

Javvad Malik, security advocate at AlienVault

“Imagine that you had been fighting with a friend for a very long time, and then that friend gave you a present to make up and told you that you’d won. That present was a beautiful wooden horse named Trojan. You’d be pleased, wouldn’t you? But what you didn’t know was that inside the horse were a load of ants that seeped out of the wooden horse and got into your computer. They got into your keyboard and recorded everything you typed, they got into your webcam and recorded everything they saw.

“If you’d been telling another friend your secrets on chat, they could tell everyone and embarrass you. The ants could also delete all the high scores off your favourite games so that your friend would be on top of the leader board, instead of you. These Trojan ants would let your friend see inside your computer without you realizing that anything was wrong. The moral of the story is that you shouldn’t accept a present if it looks suspicious!”

Jonathan French, security analyst at AppRiver

“Trojan Horse malware is when a user tries to install software that looks like it will be helpful, but it turns out to be bad. Malware authors use this method because it works on many people and victims willingly install malware under the assumption its software that does something else. So, let’s say you love cake. There’s all sorts of cake you like and all sorts of bakeries you go to and get cake from. One day, you go get your cake like normal. You eagerly swallow a bite of the cake. But unfortunately, you notice too late that instead of sugary icing and strawberry filling, your cake this time was covered in shaving cream and filled with peppers. While you did willingly eat that cake, it was under the assumption it was going to be delicious. In this case you were victim of a Trojan Horse Cake, where you thought the cake was going to be something you wanted, but ended up being gross.”

Joe Evans, technical manager, Barracuda Central

“A Trojan Horse is a baddie in disguise that tries to attack your computer. He pretends to be a regular email or programme and then – when you least expect it – gives your computer a virus. A Trojan Horse can be hard to spot because they are good at making you believe they are harmless. To avoid falling for their tricks you must think twice before opening any email attachments or installing any programmes to your computer. Remember, a Trojan Horse may look like your friend or convince you he is trying to help, but when you invite him into your computer he can turn nasty and cause some serious damage.”

Sian John, chief security strategist EMEA, Symantec

“Just like Mystique in XMen disguises herself as another person to fool people into thinking she is their friend, a Trojan horse does something similar and changes its appearance to get on your computer. A Trojan might disguise itself as an app or game you have played before so that you will click on it and download it onto your computer. Only once you have downloaded it will the Trojan horse reveal its true identity and can steal information about you and access your personal files.”

Csaba Krasznay, product manager at Balabit

“Do you remember for those monsters in your closet? You don’t really know how they got inside your furniture but you knew that they did bad things and they scared you. And you don’t understand why your parents chose that wardrobe with the ugly thing inside it.

“Trojan horses are very similar to this. It’s like your parents have downloaded something from the internet that seemed to be beautiful. But they didn’t count on the “little surprise” in it that would do bad things with the computer. These so called malware will also let other nasties onto the computer.

“Think of it like in the movie Monsters, Inc,, you might have your own private monster, but there are several others in the factory. Your parents might have a private Trojan horse which will let the others in. And I can assure you, your parents will be REALLY scared when they realise their monster in the closet, I mean, on the PC.”

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