Learn about common types of malware and their purposes

Malware is short for malicious software. Malware describes viruses, worms, trojans, spyware, ransomware and other malicious programs.

The cyber criminal’s goal is to cause your computer to malfunction, cause damage, disruption or gain unauthorised access to your information for financial gain.

Different malware programs are designed for different purposes including:

  • monitoring your keyboard strokes to obtain passwords or credit card details
  • monitoring incoming and outgoing emails
  • locking all your files and asking you to pay a ransom to retrieve the key.

Ransomware attacks are becoming more frequent

Worldwide, criminals are distributing a type of malware called ransomware at a prolific rate.

This malicious software is spread using convincing emails such as traffic infringement notices, parcel collection notices, and electricity bills.

Once installed on a computer, ransomware encrypts (locks) all of your files – documents, photo, videos, music – making them completely inaccessible.

It then presents a pop-up window demanding a ransom to be paid in order to regain access to the files.

Unfortunately without the encryption key, it is impossible to regain access to the files.

Put measures in place to prevent attacks

Keep your software up to date

Malware is always changing as criminals get smarter and smarter.

Keeping your operating system, browser and applications up-to-date is essential to help protect your computer. Ensure system updates are set to automatically update.

Visit Microsoft, opens in new window and Apple, opens in new window for further information.

Use anti-virus software

Anti-virus software can help keep your computer and mobile devices safe. Once you have it installed, make sure you keep it up-to-date.

If you’re unsure how, contact an IT professional or contact Microsoft or Apple about setting up automatic updates on your operating system.

We even provide you with a free six month offer of anti-virus.

Create backups

It’s good practice to keep copies of your important files (such as document and photos). These copies are known as a backup. You can backup your important files on a separate device to your computer, such as a USB memory stick, portable hard drive or CD. Make sure you store your backups separately from your computer.

This ensures that if your computer does become infected, you will be able to restore your files after you clean your system.

Learn how to identify a malware attack

While some types of malware such as a keylogger or a trojan may show no obvious signs, there are a few things you can look out for that might be an indication that your computer is infected:

  • Your computer takes longer than normal to start.
  • Your computer keeps crashing.
  • There are new, unfamiliar icons on your desktop.
  • Your computer is running unusually slow (for example, programs take longer than normal to load).

Also look for changes to files like:

  • files that normally should be accessible are suddenly inaccessible
  • files have been edited, though no changes in them should have occurred
  • files appear, disappear or undergo significant and unexpected changes in size.

What to do if you’re affected by malware

If you suspect that you have malware on your computer, the first thing to do is disconnect that computer from the internet and any other devices it’s networked with. This helps ensure the infection doesn’t spread from one device to others.

Confirm that your anti-virus is up-to-date and run a scan immediately.

You can find more information on Windows PCs on the Microsoft website, opens in new window, or for your Mac, check Apple’s website, opens in new window.

Depending on the type of malware, you may be able to clean the infection, or you may need to take more serious measures. If you don’t feel confident to perform these actions to clean your computer, contact an IT professional.

Helpful resources

How we can help

If you’re a NAB customer and you believe your business or personal accounts have been impacted by fraud or a scam, we’re here to help. Explore the immediate steps you can take to protect yourself and discover when you should get in touch with us to make a report.

Learn what to do in the event of fraud or scams

Get updates on the latest fraud alerts


IDCARE is Australia and New Zealand's not-for-profit counselling and support service set up to assist Australians impacted by identity theft and cyber-related crimes.

IDCARE can assist NAB customers to navigate through the process when identity details or credentials have been compromised through fraud or scams. IDCARE is a free service for all Australians.

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Australian Government | Australian Cyber Security Centre (ACSC)

The Australian Cyber Security Centre (ACSC) brings cyber security capabilities from across the Australian Government together in a single location. It’s the hub for private and public sector collaboration and information sharing to combat cyber security threats. ACSC provides topical, relevant and timely information on how home internet users and small businesses can protect themselves from, and reduce the risk of, cyber security threats such as software vulnerabilities, online scams, malicious activities and risky online behaviours.

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Australian Government | ReportCyber

ReportCyber is a secure reporting and referral service for cybercrime and online incidents which may be in breach of Australian law. The ReportCyber website provides a cybercrime reporting mechanism as well as helpful information about cybercrime.

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Australian Competition and Consumer Commission | Scamwatch

Scamwatch provides information to consumers and small businesses about how to recognise, avoid and report scams using publications, videos and other online resources.

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Australian Government | Office of the eSafety Commissioner

The Office of the eSafety Commissioner provides online safety education for Australian children and young people, a complaints service for young Australians who experience serious cyberbullying, and address illegal online content.

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Australian Government | Attorney-General’s Department

The Attorney-General’s Department website provides helpful information and resources about your rights and protections in regards to identity security, freedom of information and cyber security. The Department has developed a range of resources to assist people protect their identity and recover from the effects of identity crime.

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Important information