Malware: The Many Faces of Malicious Software

The 30-second explanation

Malware is unwanted software doing something you never agreed to: stealing information, locking your files, watching what you do, or handing control to a stranger.

How it works

1. 1

   1. Delivery

   An attachment, a download or an unpatched flaw brings it onto the device.

2. 2

   2. Execution

   The code runs, usually disguised as something ordinary.

3. 3

   3. Persistence

   It sets itself up to survive the next reboot.

4. 4

   4. Objective

   It steals, spies, spreads, or locks the system down.

Malware has to get onto a device before it can do anything. Common routes in include a fake attachment, a dodgy download, a malicious advert, or a flaw that was never patched. Once running, it gets to work: a trojan disguises itself as something useful, an infostealer copies saved browser passwords, ransomware locks files wholesale, a worm spreads itself unassisted, and a remote access tool lets an attacker sit at the keyboard from anywhere. Good defence stacks updates, cautious habits, and software that watches behaviour rather than just file names.

Real-world example

How to spot it

• Software from unofficial sources

  Cracked or 'free' versions of paid programs are a favourite hiding place for a payload.

• A device that suddenly slows down

  Unexplained CPU use or unfamiliar programs starting up on their own.

• Security tools turned off

  Malware frequently tries to disable whatever protection it finds first.

• Unexpected pop-ups or new browser extensions

  Anything showing up that you never actually installed.

What to do

1. 1Install software only from official sources, and keep both the system and its apps updated.
2. 2Run reputable endpoint protection, and resist the urge to switch it off just to get something to run.
3. 3If you suspect an infection, disconnect from the network and get help before typing in more passwords.