Viruses, Worms and Trojans Explained

Viruses, Worms and Trojans

Everyone has heard of viruses, worms and trojans but very few people a clear idea of what they are or actually do, unless of course they have been badly stung by an infection. As a set, these are called malware, which literally just means malicious software, there are further dangers which are known as Spyware and Adware, but these tend to be far less damaging.

So what’s the difference?

A virus generally attaches itself to a program and usually comes in through email; when the program is clicked on, then the virus is executed and spreads through email, attaching itself to the mail that you have sent.

Worms arrive in a similar way to viruses but have the ability to spread over networks and self-propagate. They do this by emailing everyone in your address book and can be much more damaging than a virus. They are however, often easier to spot as they sometimes damage the operating system (OS) and programs that are installed on your machine.

This may cause programs to shut down automatically as soon as they’re clicked upon, which is something of a giveaway. However, it should be borne in mind that no malware currently exists that can damage the hardware of your computer – malware infections are curable and far too many people believe that their computer is damaged beyond repair. This isn’t the case, in many cases they can be cleaned by a computer technician without losing date (which should be backed up anyway) or a reinstallation of the OS.

Trojans have become much more prevalent in recent years and are often installed with genuine looking programs, quite often ones which include browser toolbars. Although they don’t self-propagate, trojans can open a ‘back door’ to your machine and allow others to control it, collect information and often download further malware onto your machine.

Why do they exist?

Put simply, to make criminals money – although they’re now being utilized around the world to perform cyber-espionage and state-sponsored cyber-attacks. Whilst the fight against malware has been going on for decades, security experts always seem to one step behind, playing catch-up as new strains are created every day.

There are a number of reasons your computer may become infected including:

·       To create a botnet

·       To steal financial information

·       To perform a DDos attack

·       To trick you into stealing your money

·       Identity theft

Early beginnings

Hackers used to be regarded as professionals who tested networks and software to ensure that it was secure and unable to be accessed by third-parties. Now, a hacker is thought to be some young computer nerd that devote their lives to causing problems, stealing info and bragging about it to other ‘script kiddies’, as they used to be known. Whilst professional hackers still exist, they rarely make the news like the new hacker does; there are also groups known as hacktivists who attack large corporations for political reasons.

Early viruses had the ability to actually damage the hardware on your computer, but this is no longer the case (so please do ignore the email that circulates as a virus that will damage your hard drive, it’s a hoax).

Why use security software then?

Because whilst your machine may be fixable, if you become infected with malware then a number of things can still affect you personally. Banking trojans are very common and have become more and more sophisticated, tricking you into thinking that you’re logging into your online banking, whilst all the time you’re typing your info into a dummy page that looks like the real deal.

This, of course, enables them to empty your accounts, at best; trojans collate information such as credit card details too. So, a trojan may include a keylogger which allows the controller to access every keystroke you make on your machine, thus finding credit card and social security numbers and more. Think about what you type and then ask yourself why you need protection.

Many security vendors now sell security suites, which scan links to ensure they’re not malicious, protect your identity and much more. It’s vital that these are installed and kept up to date.

Alongside this, especially if you are one of the many Windows users in the world, it’s vital that you not only allow the OS to perform automatic updates, but it’s also important that your browser is always updated along with third-party software such as Adobe, Java and Office products.

This is because as cybercriminals find new ways to exploit software, security experts are constantly plugging that hole with updates to protect you from threats that have been recently discovered.

Botnets and DDoS attacks

Botnets are used for a variety of reasons; sending out large amounts of spam or performing Distributed Denial of Service (DDoS) attacks on websites. Basically, a botnet is constructed from a large number of infected machines known as ‘drones’ or ‘zombies’; these machines are controlled by criminals via a Command and Control (C&C) server.

Spam is sent via drones automatically, without the user knowing it’s happening (unless they keep an eye on their bandwidth). DDoS attacks serve a different purpose; the drones are all sent a command to send traffic to a specific website, causing it to become overloaded and go down.

Often, this is done for the purpose of blackmail; imagine how much money gambling sites make in an hour, if they went down for any length of time they would lose millions.

A recent, highly publicized botnet has been DNSChanger; this was dismantled in November by the FBI, but because of the way the malware redirected machines to its own servers, the FBI had to set up alternative servers to give infected machines time to clean up.

However, last week when the FBI finally shut down their servers, it was thought that 300,000 machines worldwide were infected. The majority of these were in the USA, with European countries not far behind. DNSChanger is simple to fix and currently ISPs are stepping into the breach with their own servers so that more people can still get online and clean up. For more information and a fix-tool, the FBI has a section on its website about how to remove the malware and more information on it.   

I use a Mac, so I can’t get infected right?

Wrong. Whilst the Windows platform is still by far the most attacked, Macs recently suffered a botnet attack thought to have infected 600,000 computers worldwide. For many years Mac users have thought themselves invulnerable, supported by Apple’s advertising, this is no longer the case and you should ensure that you have security software installed.

Windows has taken the blame for the state of the cybercriminal underworld, now worth more than the drugs trade in monetary terms. This is because many of the products that Microsoft bring out have vulnerabilities which have yet to be patched and criminals exploit these.

It’s thought that Linux-based systems such as Ubuntu are the most secure as they have included security measures from the beginning which are continuously updated by the extensive open source community that are involved with the Linux project.

Social media – the newest threat

Social media sites represent one of the biggest threats online today; this is due to a term known as ‘social engineering’ which tricks users into sharing hoaxes, spam and malicious photos and videos.

These often have sensationalist headlines involved celebrities or saying things such as “look what this dad walked in on his teenage daughter doing”. This tempts people to click or share and often lead to either malicious websites, malware infection due to hidden code overlaying an image with a transparent layer, or the most common, survey scams.

Survey scams invite you to view the content they are offering once you have filled in a survey or 10; this results in at best, unwanted sales calls, or at worst, being signed up to premium rate services that charge a lot of money for each SMS you receive from them.

If in doubt, don’t click – Google the title and details and you will know in seconds if it’s a hoax, scam or spam that you are innocently sharing with friends. A brilliant resource for checking all types of spams, viruses and more is Hoax Slayer, this man has been working tirelessly to reveal every scam going since 2002.

Hoaxes that pull on your heartstrings are very common on Facebook, but don’t be fooled, that picture of a sick child which promises that Facebook will donate a cent for every like is nothing more than an individual who trolls for likes and shares. The families of these children often have no idea that the image of their child is being used in this way, let alone given permission.

The bigger picture

The threat represented by malware to the internet is much more than a personal one though, it’s something that every nation is becoming wise to as a means for cyber-attacks on national infrastructure, terrorist attacks and cyber-espionage.

The Stuxnet worm was created, for example, to attack an Iranian power plant and make its main engine spin out of control. Duqu, often dubbed ‘the son of Stuxnet’ also attacked Iran, but was less potentially damaging as it collected industrial and governmental information.

Further to this, a serious attack could take out national power grid and emergency services, if you consider how much of our society now relies on technology and the internet, then it’s easy to see why it’s so necessary to protect both your machine and the rest of the internet.

This week both the US and the UK have highlighted the issue in the media, governments are waking up to the threat that cyber-attacks pose and there’s little doubt that the attacks on Iran were state-sponsored. Bearing this in mind, the public also need to wake up, learn how to protect themselves and help security experts start to win the cyber war that they have been losing for decades.

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