A quick & dirty guide to malware (part 2: viruses)

A dialogue screen shown by Virus:W32/Duts.A

This is the second posting in a three-part series covering common threats a user may encounter.

This series serves as a rough and ready guide, highlighting key features and trends relevant to most users.

The One That Left

Last week I spoke of Trojans, Viruses and Worms as The Big Three. I lied a bit, though. Viruses – as a distinct malware type – probably shouldn’t be on that list any more.

Viruses have always loomed large in users’ minds as the poster child of malicious programs – heck, we even call it the anti-virus industry. In the last 10 years or so however, the number of virus infections has nosedived; our Labs, which once dealt with viruses routinely, now sees a proper virus infection about once or twice a month. Today when people talk of ‘viruses’, more often than not what they’re describing is technically a trojan or a worm, and they’re using the term in a general, ‘any malware will do’ kind of way.

That’s not to say viruses are extinct; we still receive a small, if persistent, number of queries about viruses. This may be because many businesses, households and users (both in developed countries and in recently connected developing ones) still use old, out-dated, unpatched machines or programs, or haven’t yet developed a security-conscious habits.

Whatever the case, virus infections will probably still cling on to life for a weary day after, so let’s take a look at them.

Highlights of a virus

Definition of a virus given by Merriam-Webster online dictionary

The Merriam-Webster online dictionary’s bare-bones definition of a computer virus touches on important elements most users should know, so I’ll just elaborate a bit more on some key concepts:

“usually hidden within another seemingly innocuous program”

Last week I compared a virus to a parasite, because not only does it ‘hide’ in another program, but also depends on its host to function. For the virus to run, the unsuspecting user must actively launch the infected program, which in turn launches the virus.

For this reason, virus writers usually create viruses that infect executable files (especially popular programs such as word processors or media files), which have a higher chance of being run; programs with files that get passed around a lot are extra attractive, since they can affect even more potential victims.

A good example is the Microsoft Office suite which, with their huge community of business and personal users, used to be a popular target for macro viruses. We still see queries related to this virus type, though thankfully far less than previously.

“Produces copies of itself and inserts them into other programs”

If you think of the common cold virus spreading from one person to another, you’ll have a pretty good idea of why this behavior can be so damaging. When a infected file is executed, it searches for and infects new files; if the newly infected files are launched, they find and infect new files in turn, like some evil Multi-Level Marketing operation. At worst, this pattern can lead to every targeted file on the system being infected.

“Usually performs a malicious action”

The damage a virus can do by replicating and infecting new files is bad enough; its payload, a completely separate set of nasty actions, can be worse. The range of actions a virus can take is huge – connecting to a remote site, changing the desktop wallpaper, displaying silly notification messages, deleting data files…it really just depends on the virus author’s imagination and programming skills.

If you’re lucky, they’re not that good and you get failed viruses like Virus:W32/Stardust; if they’re good, then you get really nasty beasts like Virus:W32/Virut or Virus:W32/Sality.AA (one of the few viruses we still find regularly active).

Appending, prepending, cavity…who cares?

A dialogue screen shown by Virus:W32/ZMK

With thousands of unique viruses out in the wild, antivirus companies find it necessary to divide them into sub-types. Unlike trojans though, viruses don’t fall into neat categories reflecting their actions; instead, they naturally fall into groupings based on technical differences in the way they infect a file – which is  basically gobbledeegook to a user not interested in detailed analysis.

Gnerally, viruses can be divided into two groups – system infectors and file infectors. The majority of viruses are the latter and infect programs or data files. System infectors on the other hand write their malicious code to specific, critical sections of the hard disk containing the operating system, so that while the OS is running its normal routines, it’s also unintentionally executing the virus code.

Fortunately, for most users a virus’s classification is largely academic. For better or for worse, the sheer variety of possible effects each unique virus can have on a file or system makes it more practical to take each virus on a case by case basis.

Back to what’s important – why should the user  care?

So let’s go back to the original question that sparked off this series: do you really need to know if it’s a virus – as opposed to, say, a trojan or worm – infecting your computer?

Well, it helps to know because the two malware types tend affect your data and computer in different ways. As a (very) general rule, trojan infections is more about data theft and loss of control over the computer; virus infections tend to result in software disruptions or damage.

Trojans may copy and steal your data, but they don’t usually destroy the data file itself; they may stop programs from running but they don’t destroy the program. A virus on the other hand, insert its own code into a program or data file, and depending on how it does so, may either leave the host completely unharmed and functional, slightly disrupted, or completely non-functional.

Another difference between trojans and viruses that really affects the user involves disinfection. For one thing, a trojan is usually a single, discrete program – getting rid of it tends to be fairly simple, a matter of removing the malicious file and its residuals (registry keys, processes, icons, etc). Removing the trojan also generally doesn’t affect the integrity of other files on the computer.

Viruses are far more nebulous by design – they can be present in multiple files, in different locations. Identifying a virus-infected file may require scanning the entire computer to be sure every affected file is caught. Removing malicious code from an infected file or – if it can’t be saved, deleting the infected file entirely – can also be problematic if the damaged data is important or the program is a critical system component.

And this doesn’t even take into account the virus’s payload, which can produce a whole other set of worries.

If you’re still interested

Still, there is a ray of hope. If current malware trends persist, we may soon see adware or backdoors promoted to being the newest member of The Big Three, and viruses – as a distinct malware type – can finally be relegated to joining 3½” floppy disks in Computer Hell.

In the meantime, here’s some links to other, more in-depth resources on viruses:

Or partially available on Google Books:

  • “Elements of Computer Security” by David Salomon
  • “Cybercrimes: A Multidisciplinary Analysis” by Sumit Ghosh

Next

Coming soon – Worms!

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GameOver ZeuS: The Kind of Game You Don’t Want On Your Computer

Unlike Team Fortress 2 or Doom, two of the most popular PC games of all time, GameOver ZeuS is not a game you can buy online or would willingly download on to your computer. What is GameOver ZeuS? While we’ve talked about banking Trojans before, none have been as detrimental to users as the GameOver ZeuS or GOZ Trojan, which initially began infecting users in 2012. Gameover ZeuS is designed to capture banking credentials from infected computers, and make wire transfers to criminal accounts overseas. It was allegedly authored by Russian hacker Evgeniy Bogachev, who then implanted it on computers all around the world; building a network of infected machines - or bots - that his crime syndicate could control from anywhere. It’s predominately spread through spam e-mail or phishing messages. So far, it’s been estimated to scam people out of hundreds of millions of dollars and it’s only getting worse. It doesn’t stop there; Gameover ZeuS can also be modified by hackers to load different kinds of Trojans on to it. One such Trojan is a ransomware called CryptoLocker, which is a devastating malware that locks a user’s most precious files by encrypting all the files until he or she pays the hacker a ransom. In June 2014, the FBI, Europol, and the UK’s National Crime Agency announced they had been working closely with various security firms and academic researchers around the world and took action under a program dubbed “Operation Trovar.” This initiative temporarily disrupted the system that was spreading the Trojan and infecting computers, allowing a temporary pause in additional computers from being infected. However, computers that were already infected remained at risk, as they were still compromised. What’s next? The disruption of the GameOver ZeuS botnet was a great success in many ways, but it’s not over. Our security advisor, Sean Sullivan, worries that this temporary disruption was actually more dangerous than completely taking it down. “Without arresting Bogachev, Gameover ZeuS is still a huge threat and likely to evolve to become more dangerous. The hackers can just as easily program a future version of the Trojan to initiate a “self-destruct” order (like destroy every file on a computer) if the ransom isn’t paid, or if authorities try to intervene.” What can we do to protect our digital freedom? Beware of malicious spam and phishing attempts — don’t open any attachments within emails unless you are specifically expecting something. Check email attachments carefully, and make sure you don’t open any files that automatically launch, which frequently end in .exe Have an Internet security solution in place and keep it up to date Keep your Windows operating system and your Internet browser plugins updated Back up all of your personal files regularly Also, check your machines to be sure you do not carry the Gameover ZeuS Trojan. For more information on how this powerful Trojan works and how it is spread, check out this this video. [protected-iframe id="888198d18fd45eae52e6400a39fb4437-10874323-9129869" info="//www.youtube-nocookie.com/v/JhiPDbTIsqw?hl=en_US&version=3&rel=0" width="640" height="360"] Have more questions? Ask us here on the blog.  

Sep 20, 2014
Unbenannt-1

16 ways SAFE protects your devices, your family and you

In the early twenty-first century, when hackers were mostly pranksters, having security software on your PC was mostly about saving you some trouble. In 2014, international crime syndicates regularly co-opt millions of computers in order to systematically steal banking information, take identities and hold files for ransom, security isn't about convenience. It's about giving our families the freedom to live our lives online with out the threat of strangers invading our lives, hijacking our time and money. An anti-virus on one PC is a good step. But who just uses one PC now? Many of us three different devices before breakfast. That's why we created F-Secure SAFE -- it's built to protect all the devices and all of the people in your family. The latest update of SAFE is designed to make it easier to install on infected computers for a smoother overall experience. It also gives your tools to keep your devices and family safe wherever they go. 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Protect your home computer in the same way your office computer is protected Your office computer is protected by software that safeguards it against viruses and protects corporate data against theft by criminals. SAFE gives you the same options on your home computer. 3. Limit the time your children spend on the Internet. If you think that your children may spend too much time browsing the internet or playing online games, SAFE will let you decide for how many hours they are allowed to do it every day. You can easily define in which hours exactly they connect to the Internet. If they try to go online during unapproved times, the computer will not connect to the Internet. 4. Online banking protection your bank knows you need Do you know that most banks recommend in terms of security is using paid anti-virus software when banking online? SAFE ensures you meet these recommendations. 5. Safeguard your memories  F-Secure Safe protects the photos and videos of your children or grandchildren against falling into the wrong hands. The built-in anti-virus application and protection against as-yet-unknown threats ensure that all of the memories collected on your computer are fully protected. Your files will never be destroyed, encoded to demand payment for decoding them, or intercepted in order to be published or to gain profit from distributing them. 6. Protect your children against adult content Define which sort of content can be accessed by your children, whether you're monitoring them or not. 7. Shop online without worry Thanks to protection against spyware and browsing protection, your credit card number is invisible to criminals. Now you can relax when shopping online, booking hotels or buying air tickets. Tablets 1. Control which apps your kids can install Keep games that involve virtual violence, sex or gambling off your child's device with a simple setting. 2. Decide which sites your child can visit  Even if they use tablets in their rooms, you can be sure that they visit no websites inappropriate for their age. 3. Protect your device against malware with browsing protection. Protect yourself from phishing scams, ransomware and malicious apps that could be triggered by visiting the wrong site. 4. Keep login data and online banking passwords secure SAFE protects your tablet against spyware that steals your bank login data. Smartphones 1. Find your missing phone. Locate your lost phone and make sure no one can access your data should your device be stolen. 2. Find your child Check the location of your child’s phone from our simple web portal. 3. Avoid surprising charges Are you concerned that your children may install games than require additional payments? F-Secure Safe lets you control which software is installed on their phones. 4. 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Sep 15, 2014
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Why your Apple Watch will probably never be infected by malware

On Tuesday Apple announced its latest iPhone models and a new piece of wearable technology some have been anxiously waiting for -- Apple Watch. TechRadar describes the latest innovation from Cupertino as "An iOS 8-friendly watch that plays nice with your iPhone." And if it works like your iPhone, you can expect that it will free of all mobile malware threats, unless you decide to "jailbreak" it. The latest F-Secure Labs Threat Report clears up one big misconception about iOS malware: It does exist, barely. In the first half of 2014, 295 new families and variants or mobile malware were discovered – 294 on Android and one on iOS.  iPhone users can face phishing scams and Wi-Fi hijacking, which is why we created our Freedome VPN, but the threat of getting a bad app on your iOS device is almost non-existent. "Unlike Android, malware on iOS have so far only been effective against jailbroken devices, making the jailbreak tools created by various hacker outfits (and which usually work by exploiting undocumented bugs in the platform) of interest to security researchers," the report explains. The iOS threat that was found earlier this year, Unflod Baby Panda, was designed to listen to outgoing SSL connections in order to steal the device’s Apple ID and password details. Apple ID and passwords have been in the news recently as they may have played a role in a series of hacks of celebrity iCloud accounts that led to the posting of dozens of private photos. Our Mikko Hypponen explained in our latest Threat Report Webinar that many users have been using these accounts for years, mostly to purchase items in the iTunes store, without realizing how much data they were actually protecting. But Unflod Baby Panda is very unlikely to have played any role in the celebrity hacks, as "jailbreaking" a device is still very rare. Few users know about the hack that gives up the protection of the "closed garden" approach of the iOS app store, which has been incredibly successful in keeping malware off the platform, especially compared to the more open Android landscape. The official Play store has seen some infiltration by bad apps, adware and spamware -- as has the iOS app store to a far lesser degree -- but the majority of Android threats come from third-party marketplaces, which is why F-Secure Labs recommends you avoid them. The vast majority of iPhone owners have never had to worry about malware -- and if the Apple Watch employs the some tight restrictions on apps, the device will likely be free of security concerns. However, having a watch with the power of a smartphone attached to your body nearly twenty-four hours a day promises to introduce privacy questions few have ever considered.    

Sep 9, 2014
BY Jason