Malware Viruses: How to Detect a Virus?

Malware Viruses: How to Detect a Virus

Malware viruses are one of the most pervasive cyber threats organisations and individuals face. So much so, that malware viruses are one of the first things to come to mind when most people think about cyber attacks in general. 

In this post, we take a look at malware viruses, the various symptoms of malware, and how to know if your computer has a virus.   

What is malware and how does it differ from a virus?      

Malware is an umbrella term for all types of “malicious software”, including viruses, ransomware, rootkits, and Trojan horses. A virus, conversely, is a type of malware. People often refer to malware as viruses because they’re more familiar with the term (because viruses occur in nature) than malware.     

How to know if your computer has a virus? Look for these signs 

Let’s take a look at some of the most common symptoms of malware.

Unusual pop-ups or error messages 

Consistently seeing strange messages and notifications on your PC, especially when browsing the web, indicates you’ve been infected by malware. This may be a virus, but it could also be an adware or scareware infection.  

Adware is a form of malware that allows malicious actors to bombard your device with unwanted pop-up ads from which they make revenue. Scareware, conversely, is malicious software that causes fraudulent error messages to pop up on your device continually. The objective of scareware is to make you alarmed or concerned enough to click on a link – which attempts to convince you to buy bogus software that purports to fix the “problem” on your device. Alternatively, the scareware links can take you to a website that infects your device with more malware viruses. 

Slow or unresponsive computer performance 

A slow device is another sign you’ve been infected with malware viruses. There’s a chance that the virus is multiplying itself as it infects more files and applications on your device, increasingly sapping system resources. Alternatively, you may be suffering from a denial of service attack (DoS) or a distributed denial of service attack (DDoS) attack executed by a botnet.  

Subsequently, if your device frequently freezes or crashes, this is another sign your computer has a virus. Often, viruses can alter, delete, or corrupt crucial system files, compromising the operating system’s stability and preventing specific applications from executing properly.  

Suspicious emails or downloads 

If your computer has a virus, cast your mind back to any suspicious emails you may have opened and on which you clicked on links. Similarly, if you attempted to download any software, particularly if it was trial software or presented itself as a free version of an application you’d usually pay for, that could result in a malware virus infection.   

On a similar note, if you discover that suspicious emails have been sent from your email account to people on your contact list, that’s another indication you’ve been infected with a malware virus.  

Changes in your system settings or homepage 

Because malware viruses can attack your system settings, particularly in an effort to avoid detection or disable anti virus software, you must look out for changes to your system configurations. Worse still, if you notice files have been deleted, you may have been infected with an overwrite virus that can delete your files and replace them with infected replicas.   

Additionally, changes to your browser homepage are another symptom of a malware virus infection. Browser hijackers are a form of malware that change your browser settings to redirect you to malicious sites where they can serve ads, get you to click on phishing or pharming links, or, naturally, infect your device with more malware. Another clue that you might have picked up a browser hijacker is a change to your preferred search engine. If, for instance, you usually use Google and find that your web searches are giving you Yahoo search results, scan for malware viruses immediately.  

What to do if you suspect your computer has a virus 

Scan your device with anti virus software 

Anti virus software is one of the most efficient ways of detecting if your computer has a virus, so running a full scan of your device or network is the first thing to do if you suspect a malware infection. The scan will detect all malware viruses on the device and allow you to quarantine them for further analysis (by cyber security teams to gather new threat intelligence) or eliminate the threat altogether.  

Remove suspicious programs or files 

You should remove any unfamiliar or suspicious files that appear on your device, namely on your downloads folder, desktop, and program files, where malicious programs often end up by default. You should be especially wary of .exe files: executable files that can contain programs that deploy malware and determine its effects. Fortunately, a good anti-virus solution will usually automatically identify and remove suspicious and potentially malicious files during a scan.  

Additionally, if you notice strangely-named running processes when you run Task Manager, that could be a virus – especially if it uses a strange amount of system resources and/or has multiple instances.  

Change your passwords and secure your accounts 

As it’s possible you were infected with malware because a hacker got ahold of your access credentials, you must reset your passwords to prevent further unauthorised access. Similarly, if you found you’ve been logged out of certain applications and services, you could have been hacked or infected with malware viruses. As a security and preventative measure against future computer virus infections, you should reset your passwords – ensuring they’re markedly different from your previous ones.   

What should I do if I suspect my personal information was stolen due to malware or a virus?  

If you suspect that your sensitive data has been stolen as a result of a virus or malware infection, you should: 

1. Run a scan for malware viruses 
2. Restore your system to a backup prior to when you suspect your data was stolen 
3. Remove any offending files or software 
4. Reset your passwords and, where possible, turn on multi-factor authentication.  

Ideally, to be extra certain you’ve eliminated the threat, you should wipe your device and then reinstall the operating system – provided you have an uncorrupted backup.

How to protect your device from malware viruses 

Keep your anti virus software up-to-date 

Consistently keeping your anti virus solution up to date is essential for protection against malware viruses. As malicious actors are constantly developing new malware viruses and refining existing forms to be increasingly dangerous and undetectable, anti virus software developers have to constantly update their database of known viruses. Subsequently, they push these enhancements out through updates, which is why applying every patch, fix, and update put out by the developer is essential.  

Be careful when clicking on links or downloading files 

Clicking on enticing malicious links is one of the most frequent methods of malware viruses finding their way onto a device. Commonly, this results from the user attempting to download a file, such as a movie or software, which instead turns out to be malicious software. Similarly, a user may have been watching a TV show on an illegal site and absentmindedly clicked on a pop-up ad that then infected their device.  

Unfortunately, however, you don’t even have to click on a link to be infected with malware viruses, as they could end up on your device as a result of a drive-by download. Instead of requiring some action from the user, drive-by downloads capitalise on vulnerabilities within a device’s hardware or applications to install malware or viruses.  

Use a firewall and secure your WI-FI network 

A firewall inspects incoming traffic, proactively protecting you from malware viruses by prohibiting suspicious-looking data. Firewalls also prevent connection to websites known to contain malicious code.   

However, it’s also essential to secure your Wi-Fi network to prevent actors from accessing your IT infrastructure and infecting it with malware viruses. This includes, first and foremost, changing the default passwords of your routers, switches, etc., and replacing them with strong passwords, which you change frequently as per your access control policies.  

Is it possible for malware or viruses to affect my mobile devices? 

It is indeed possible for malware, including viruses, to infect your mobile device, with a growing amount of malicious code designed specifically to attack smartphones and tablets. Common forms of mobile malware include viruses that attack banking apps and digital wallets, ransomware that locks devices, and rootkits that give hackers remote control over your device.

How RiskXchange can help you identify symptoms of malware viruses and protect your IT Infrastructure

We can help you identify if you’ve been infected by malware and identify which parts of your IT infrastructure and current cyber security controls and policies leave you most vulnerable to the growing threat of malware.  

Contact us for your free cyber risk score assessment and begin strengthening your company’s cyber security posture today.