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


Coming soon – Worms!

More posts from this topic


Tricks Not Treats: The 5 Scariest Online Threats

The first known use of the term "trick or treat" was found in a November 1927 edition of Blackie, Alberta's Canada Herald: Hallowe’en provided an opportunity for real strenuous fun. No real damage was done except to the temper of some who had to hunt for wagon wheels, gates, wagons, barrels, etc., much of which decorated the front street. The youthful tormentors were at back door and front demanding edible plunder by the word “trick or treat” to which the inmates gladly responded and sent the robbers away rejoicing. "No real damage" from "youthful tormentors?" Sounds a lot like the early days of hacking. Unfortunately those days are long over. “It’s a business,” F-Secure's Chief Research Officer Mikko Hyppönen told Wired UK. “There’s a whole structure there that’s needed,” F-Secure's "Cyber Gandalf" Andy Patel told ITPRO. “An individual can’t just go in and do this now; it’s not a one man job… these are companies.” The cyber crime "industry" has raked in hundreds of millions and possibly even billions of dollars. And it does it, in general, by counting on people to make mistakes. “People do stupid stuff,” Mikko explained. “You cannot patch people.” The first step to avoiding a threat is knowing it exists. So this Halloween as you search for treats online, look out for these tricks. Ransomware F-Secure Labs has warned about malware that holds your digital files hostage to demand a ransom for most of the last decade. But it's in the last year that the threat has burst into the mainstream and become something you can't go a few weeks without hearing about it on the news. How do you avoid this trick? Keep your system software updated and run security software at all times. Make regular backups of every file that matters on your computer and never click on attachments and links in emails that you weren't expecting. Find My iPhone Scam This scam answers the question, "How can losing your iPhone get any worse?" People who use the "Find My iPhone" app have been targeted by criminals who've gotten ahold of their phones with a scam that allows the crooks to gain access to the device and -- possibly -- the owner's most intimate financial details. How do you avoid this? Check the URL before entering any confidential data. Or as Apple says, "You should never enter your Apple account information on any non-Apple website." Phishing Scams As cyber criminals have gone pro, they've gotten better at using old tactics that we thought had faded away -- like email attachments and phishing scams. Like the trick that gives crooks access to stolen iPhones, a phishing scam just tricks you into entering your private credentials into the wrong site. And it then uses those credentials to hack your email, financial accounts, etc. Checking URLs before entering data is crucial because with the explosion of photo editing software and skills, it's now easier than ever to make a fake site look real. Experts believe that one wrong click to a fake site led the chair of a major presidential campaign to expose his entire inbox to the world. Having someone else leak your password Millions and millions of passwords have been leaked in 2016, some from breaches of data that took place years ago. It might not sound scary that your Yahoo! password from 2005 is now public, except if you are still using that password today on a critical account. This is why you need to use strong, unique password for each important account. Yes, remembering all that is almost impossible. So consider using a tool like F-Secure's KEY to manage your passwords. KEY is free to use on one device. Haunted IoT devices As our homes are getting smarter by connecting almost everything to the internet, they're also getting haunted -- by cyber criminals. A botnet is a network of computers that have been hacked and "enslaved." Security expert Brian Krebs was recently hit by a monster attack on his site that he believes was powered by a botnet powered by "'Internet of Things,” (IoT) devices — routers, IP cameras and digital video recorders (DVRs) that are exposed to the Internet and protected with weak or hard-coded passwords." What can you do? So much of this problem requires manufacturers to improve their security. But you can help by keeping every device updated with the latest software from the manufacturer and always changing your default passwords.  [Image by Daniel Lewis | Flickr]

October 21, 2016
dead end

Should We Stop Thinking of Email As Private?

When he was still working in cyber security for the Finnish government, Erka Koivunen met a NATO diplomat that there was "nothing new" about the era we now live in. Foreign envoys have always lived with the constant awareness that their private communications could be "leaked" for their enemies to exploit. "Anything that was written down could eventually be discovered," Erka, who is now an F-Secure Cyber Security Advisor, told me. "So the most sensitive conversations never took place in writing." Given the massive email leaks that have now hit the worlds of business, with the Sony hacks, and politics, with the leaks of U.S. political figures, is this how we should all start thinking? Does everyone alive in the twenty-first century have to operate like a NATO diplomat? Or a C-level executive who knows any word she types could be subpoenaed? Or the campaign chair of a presidential campaign? The answer, unfortunately, seems to be increasingly clear. "Whatever you write, you may need to defend your position in public," Erka said. Relying on an insecure medium The problems with email begin with the general insecurity of it as a means of communication. It's more like sending a postcard than sending a sealed letter, Erka explains. "As soon as the message goes out of your or your company’s systems, you lose control of it," Erka explained. "This is by far the biggest problem of the good-ole-email. Messages can be eavesdropped, altered, delayed, replayed or dropped altogether without you ever knowing." To actually spy on email as it's being transmitted generally requires legal access to telecommunications infrastructure or extraordinary technical knowhow and resources. Think law enforcement or intelligence agencies. Since these groups have a vested interest in cloaking their activities, they had little incentive to engage in the massive sort of leaking of gigabytes of private data we've seen from Wikileaks. However, we appear to be at the end of the era of "the gentleman's agreement" between countries, as cyber policy expert Mara Tam explained on a recent episode of the Risky.Biz podcast. This agreement went something like: "Gentlemen read each other's email, but they don't leak it to the public." The leaks from former CIA contractor Edward Snowden helped make the public aware of how much information the government potentially could access. But the exposure of a private individual's digital communication to the world presents a stark new reality for anyone who conducts business online. "Personal mailboxes store gigabytes’ worth of conversation history that will be a treasure trove for attackers for multiple reasons," Erka said. "There are sensitive discussions about business strategy, customers, competitors, products. There is also internal gossip, badmouthing and other damaging stuff." Activist Naomi Klein told The Intercept that "this sort of indiscriminate dump is precisely what Snowden was trying to protect us from." And we don't yet have a full sense of the potential ways this mass of data can be used against us. A competitor could use private information to tarnish someone’s reputation and hackers can mine the data to prepare for future cyber intrusions or to gain access to your other accounts through password resets. Letting the public decide what's private Leaks have already cost some executives their jobs and could swing the U.S. presidential election. But in a sense, we're all victims of this new risk to all of our privacy. "Whatever you write in an email you have to consider, are you ready for your boss, your spouse, your business partners to read it?" Erka asked. This new reality leads inevitably to the tragedy of self-censorship. Zeynep Tufekci -- a "techno-sociologist" -- ‏has been doing a running commentary on the Wikileaks revelations and is very disturbed by what she's seeing. "People gossiping in internal conversation is not a scandal—but destroying public/private boundaries will paralyze dissent, not the powerful," she tweeted. Wikileaks is releasing more documents than it could ever sift through in the hopes that the newsworthy information will be discerned by interested researchers around the world. But along with potentially relevant items, intensely private information has been revealed. "For example, a suicide attempt was publicized through Podesta indiscriminate dump (Wikileaks tweeted it out)," she noted. "Who will want to be political?" This makes the loss of email seem dire, but perhaps it speaks to a not just a flaw in the medium's security but the medium itself. "The deeper problem with email is that it has never quite settled on a social mode," The New York Times Farhad Manjoo wrote. "An email can be as formal as a legal letter or as tossed off as drive-by insult. This invites confusion." What can you do? So, should you be like that NATO diplomat content to keep all of your deepest secrets out of writing? Can you expect yourself to remove all snark and potentially offensive thoughts from your emails? Should you assume that your email box is like a box of letters in your attic, vulnerable to anyone who can get access to it? These answers are ultimately up to you and how you use -- or don't use -- email. F-Secure security advisor Sean Sullivan has found that young people he's interviewed are increasingly abandoning email as communication tool. "They only have an account -- typically Gmail -- in order to sign up for stuff," he said. If this continues, email is on its way out, whether it's private or not. For now, lawyers, doctors and other professionals with explicit legal responsibilities, email has a much more defined role that cannot be easily abandoned or circumvented. As far as your work email goes, consult your IT staff for guidance as you may be under legal obligation to preserve your data. But for your personal email, Erka suggests you have to at least be aware of how likely you are to be a target and what you can do to contain any potential damage -- besides using a strong unique password for every email account you have and only entering your account information on the secure webpage of your email provider. If you are involved in international politics, for instance, there's no question. You are a target. Hackers are either after your emails or are trying to get access to powerful people in your contacts. If you're someone with no power, no tumultuous relationships and no interest in politics, you're likely not to be on anyone's radar... yet. The problem is no one knows where you'll be in a few years and our inboxes are big enough to last a lifetime. "When everyone is using cloud-based emails like Gmail, there's no need to save space," Erka said. "That's the whole selling point of those services: Never delete anything." If you see the potential for enough damage, you many want these recent leaks as an inspiration to launch a serious spring cleaning of your personal online inboxes, including email and social media. "You may want to delete the messages you don't need and sort the stuff you do want into folders that you take off the web and can store on a secure backup," Erka suggested. Yes, you will lose the convenience of being able to search your Gmail box through a simple interface, but so will potential hackers. He also recommends sharing documents through sharing platforms and cloud services such as Sharepoint, Salesforce or Dropbox. "These links can require separate authentication upon opening and the sender can control how long it will be valid," Erka said. "If the email gets stolen and leaked years later the chances are the link will be invalid by that time." For quick conversations, Sean suggests Wickr, which offers self-destructing messages through a mobile app or a desktop client with easy encryption, something that just doesn't exist for most email. "For professionals, Wickr has a paid service which will retain messages for a legal requirement, and will then securely delete them post-requirement," he said. Regardless of policy, employers have a vested interest in moving their staff away from an over-reliance on email for more than privacy reasons. "Actual phone calls and face-to-face discussions that get out of your chair are probably more useful than email or chat threats," Sean said. "So rather than swap from one to the other – just learn to better utilize what you work with best." These leaks offer a sobering reminder that email is not secure. But, perhaps, the more important message is that it as a means of communication, it was never very smart. [Image by Alan Levine |Flickr]

October 20, 2016

5 Things You Need to Know About the Threat of Election Hacking

Cyber security is playing an starring role in the drama surrounding the question of who will be the next president of the United States. "The security aspect of cyber is very, very tough," Republican nominee for president Donald Trump said, when asked about securing American secrets from cyber attacks during the first debate. "And maybe it’s hardly do-able." Even the integrity of the election has been put into doubt by the threat of hacking -- which may be exactly the point. The questions about cyber intrusions into the electoral system and the wild speculations those intrusions provoke can be hard to put in perspective. So here are five basic premises to help you assess the situation as this historic election transpires. It would be almost impossible to hack the entire U.S. election. The biggest reason this U.S. presidential election is unhackable is that most of it doesn't depend on computers. More than three out of four Americans will vote on a paper ballot this November 8, Techcrunch's Ben Dickson reports. And the fact that all Americans don't vote in the same manner points to the biggest reason you probably couldn't hack the election. Each state has its own system, with some federal guidance. Nearly every state lacks sufficient funding to fully upgrade their systems, hence the reliance on outdated technology. So while voting machines are definitely vulnerable to hacking, hitting just the right ones in a systematic way that just happens to sway the electoral college vote in favor of one candidate would involve both a massive investment of time and money and an even larger serving of luck. But that doesn't mean an election can't be "hacked." “To ‘hack’ a US presidential election, all you need to do is to obviously tamper with one county’s system, then leak that the tampering occurred,” our security advisor Sean Sullivan told Dickson. “Many people will rush to assume that all of the other typical issues that occur may also be the result of hacking — and thus, you’ll end up delegitimizing all of the results.” A delegitimized election equals a  delegitimized winner. You don't even have to hack an election to hack an election. The hacks of the Democratic National Committee and Hillary Clinton's campaign chair John Podesta could end up being far more consequential in swaying the election than hacking either voting processes or actual vote counts -- especially if the resulting leaks end up revealing something extraordinarily damaging to the candidate in the documents being dripped out by Wikileaks. “Owning an election is gold; being able to influence it is silver; knowing the outcome in advance is bronze,” F-Secure cyber security advisor Erka a Koivunen explained. It's pretty clear that someone is at least after the silver in this election. Someone has definitely poking around in the U.S. election system. The United States has been clear that it believes that Russia is trying to hack this election. This month U.S. officials have explicitly stated that the Russians are behind the hack of a contractor that works on the electoral system of the key swing state of Florida. Similar hacks were reported by the states of Arizona and Illinois. U.S. intelligence also believes Russia is behind the hack of Podesta's emails and a security firm believes it found evidence that the nation led by President Vladmir Putin was behind the hack of the DNC. Russian Foreign Minister Sergei Lavrov told CNN that the accusation that it was behind the Podesta hack "flattering." When pressed to confirm or deny his nation's involvement, Lavrov said, “No, we did not deny this, they did not prove it." Trump himself questioned whether the hack actually happened in the second debate and if he's concerned about Russian hacking, he doesn't seem to be showing it. At one point he even -- jokingly, he said later -- asked Russia to hack his opponent's missing emails. Election technology needs to improve quickly. It's safe to say that no matter who is hacking the U.S. elections, the U.S. is probably hacking them, too. The richest nation on Earth is just not engaging, as far as most people can tell, in the leaks that have followed the recent U.S. hacks. In this new era of cyber attacks backed by nation-states or "privateers" employed by nation-states the rules of cyber espionage are unclear and the fog is thick. No matter what happens in 2016, digital technology will play ever-increasing role in both campaigns and election, and the U.S. needs to take steps to ensure the integrity of its elections. Sullivan believes that the Department of Homeland Security should go through with its proposal to declare voting system critical infrastructure and then adapt its defenses to catch up with the threats. “Network monitoring is rapidly becoming a requirement,” he told Techcrunch's Dickson. And voting must be made to feel at least as secure as using your credit card to buy a coffee. “Smartcard technologies are available in several European countries for online identity authentication,” Sullivan said. “They aren’t widely used. If a country such as the United States were to get serious about rolling out such tech, it would be a game changer.” All of this focus on the security of election systems means that there are “more people checking stuff.” The question now is who is putting in more resources -- the attackers or the people doing the checking. [Image by Maryland GovPics | Flickr]

October 13, 2016