Malicious software (“malware”) is one of the most common ways law firm computers and networks are infiltrated and compromised by cyber criminals. The malicious intent behind malware usually involves gaining unauthorized access to computers or networks to steal money, passwords or valuable information, or to cause disruptions or destroy data. Malware can affect individual computers, firm networks and even the operation of the Internet. In many cases, people will not know their computer is infected with malware. Worse yet, removing malware from a computer is often very difficult.

There are many types of malware and they usually do one or more of the following tasks or damaging things:

  • Record your keystrokes to capture usernames, passwords, credit card numbers and other personal information you enter while making purchases or doing online banking. This information is then sent to cyber criminals who will use it to hack your online accounts or systems.
  • Create a “backdoor” that allows hackers to access your computer or network without your knowledge by bypassing normal authentication and security mechanisms.
  • Disable your security settings and anti-malware software so the malware won’t be detected.
  • Use your computer to hack into other computers on your firm’s network.
  • Take control of individual programs and even an entire computer.
  • Use your computer to send email messages to the people in your address book, who will in turn become infected if they click on links or open attachments in these messages.
  • Use your computer to send spam to thousands of people, usually with the intent of infecting them.
  • Steal the data on your computer.
  • Alter or delete your files and data.
  • Display unwanted pop-up windows or advertisements.
  • Slow down your computer or network or prevent access to your firm website.
  • Allow someone to secretly watch you through your webcam.

Malware employs varying mechanisms to self-replicate and infect other computers. Malware often requires some kind of deliberate action by a user to infect a computer or hijack an online account. For example, you can become infected with malware by doing the following things – most of them are common tasks that occur many times a day in every law firm:

  • Opening an infected email attachment.
  • Just visiting a website (no need to click on a link).
  • Triggering a download by clicking on a link on a website.
  • Triggering a download by clicking on a link in an email, instant message or social media post.
  • Plugging an infected USB stick or external hard drive into your computer.
  • Downloading a program to your computer, or an app for your tablet or smartphone.
  • Installing a toolbar or other add-on to your browser.

Documents created on an infected computer can be silently infected, and if those documents are sent as an email attachment, anyone opening them can be infected. USB sticks or external hard drives that are plugged into an infected computer can become infected, and they in turn can infect other computers they are then plugged into.

Once malware gets into a firm network, it will often spread to other computers on the same network. As they often have mixes of people from many different firms or online communities, deal rooms and document sharing sites can be a breeding ground for malware. In some cases the computer user doesn’t have to do anything – some types of malware (e.g., worms) can spread on their own without
any user actions.

While viruses and worms are the most common types of malware, there are many other types which are described in more detail in “Common types of malware”.

For more info on the cybercrime dangers law firms face, and the steps that you can take to avoid them, please see the Cybercrime and law firms issue of LAWPRO Magazine.