“Malware,” is a combination of the words “malicious” and “software,” and is used as an all-encompassing term for threats to a computing environment (such as viruses, spyware, adware, and other potentially harmful software installed without a user’s consent or knowledge). A report issued by Internet Security teams at Symantec and Verizon revealed that nearly one million new malware threats are released daily. There are a number of methods whereby these types of software can get into your system, including:
- Links in email, social media websites, or instant messages
- Clicking on popup ads
- Downloaded software, including mobile apps
- Infected email attachments
- Infected removable storage media (e.g. portable drives)
Some categories of malware are:
- Viruses are a kind of self-replicating software that can slow down or cripple systems, and steal, destroy or alter data.
- Computer Worms spread over computer networks by exploiting operating system vulnerabilities. Computer worms can be classified as a type of computer virus.
- Adware displays annoying pop-up ads. Some adware is solely designed to deliver advertisements, but it is not uncommon for adware to come bundled with spyware (see below) that is capable of tracking user activity and stealing information.
- Spyware is software that spies on computer users’ activity to steal personal information (passwords, online banking credentials, etc.). A “keylogger” records what you type and sends it back to a cyberthief.
- Ransomware typically spreads like a normal computer worm (see above) ending up on a computer via a downloaded file or through some other vulnerability in a network service. The ransomware restricts user access to the computer either by encrypting files on the hard drive or locking down the system and displaying messages that are intended to force the user to pay the malware creator to remove the restrictions and regain access to their computer.
- Scareware mimics a legitimate antivirus or anti-spyware service (usually in a pop-up form), saying that a computer has been infected, then encouraging users to download (and pay for) a fake security solution. The downloaded software is usually spyware.
- Bot/Botnets A bot is a software program created to automatically perform a specific operation. Bots can be used in botnets (networks of infected computers) which may be used for illegal activities, such as sending spam emails, scraping server data, distributing malware, or for “denial of service” attacks.
Symptoms of a Malware Infection
Computers that are infected with malware may exhibit any of the following strange computer behavior (not all inclusive):
- Increased CPU usage
- Slow computer or browser speeds
- A lot of pop-up windows or unexpected messages on screen
- Unexpected appearance of browser toolbars or change in browser home page
- Problems connecting to networks
- Freezing and/or crashing
- Modified and/or deleted files
- Sudden appearance of programs, icons, or files with unknown names
- Programs running, turning off, or reconfiguring themselves on their own (malware will often turn off antivirus or firewall programs)
- Emails being sent automatically without user knowledge
Malware Removal and Prevention
If you suspect infection, you should:
- Download the most recent definitions for your antivirus and anti-spyware software
- Run a full scan using both tools (this will usually be much more in-depth and will take longer than the regular monitoring scans)
- Follow the software’s instructions to remove suspected malware
- Reboot your computer, if necessary
If removing malware this way doesn’t work, or if the malware returns when you reboot your computer, you should seek professional help.
There is no guaranteed way to keep malware out, but there are several best practices that organizations and individual users should follow to prevent malware infection:
- Install and run anti-malware and firewall software. Choose a program that offers tools for identifying, quarantining, and removing many types of malware (viruses, spyware, adware, Trojans, worms).
- Keep software and operating systems up-to-date with vulnerability patches.
- Be very careful when downloading files, clicking on links, opening attachments. If something comes from a strange source, do not open it.