Understanding and Recognising Malware: Threats, Signs, Defences
Malware (malicious software) comes in many forms, each designed to harm your devices or steal your information. Recognising potential signs of infection is key.
- Common Types of Malware:
- Viruses: Attach themselves to clean files and spread, infecting other files.
- Worms: Self-replicating malware that spreads across networks without human intervention.
- Trojans (Trojan Horses): Disguise themselves as legitimate software to trick users into installing them. Often create backdoors for attackers.
- Ransomware: Encrypts your files or locks your device and demands a ransom payment for their release.
- Spyware: Secretly gathers information about your online activity, keystrokes, and personal data.
- Adware: Displays unwanted advertisements, often in pop-ups or by redirecting your browser.
- Botnets: Networks of infected computers (bots) controlled by an attacker to perform malicious activities like Distributed Denial of Service (DDoS) attacks or sending spam.
- Rootkits: Designed to gain administrative-level control over a system while remaining hidden.
- Fileless Malware: Operates in memory without writing files to disk, making it harder to detect.
- Signs of a Malware Infection:
- Sudden Slowdown: Your computer or internet connection becomes unusually slow.
- Frequent Crashes or Freezes: Applications or the entire system crash or become unresponsive more often.
- Unwanted Pop-ups and Advertisements: Excessive pop-ups, especially those that are difficult to close or lead to suspicious websites.
- Browser Homepage or Search Engine Changes: Your browser's homepage or default search engine changes without your consent.
- New Toolbars, Extensions, or Icons: Unfamiliar toolbars, extensions, or icons appear in your browser or on your desktop.
- High Network Activity: Unexplained high network usage even when you are not actively using the internet.
- Antivirus Software Disabled: Your antivirus or security software suddenly stops working or cannot be updated.
- Files Modified, Deleted, or Encrypted: You find files are missing, have been changed, or you receive a ransom note.
- Unusual Account Activity: Friends report receiving strange messages from your email or social media accounts.
- How Malware Spreads:
- Email Attachments and Links: Opening malicious attachments or clicking on links in phishing emails.
- Malicious Downloads: Downloading infected software from untrusted websites or P2P networks.
- Exploiting Software Vulnerabilities: Malware can exploit unpatched vulnerabilities in your OS or applications.
- Infected Removable Media: Plugging in an infected USB drive or external hard drive.
- Malvertising: Clicking on malicious advertisements on legitimate websites.
- Prevention Measures:
- Install and maintain reputable antivirus/anti-malware software.
- Keep your OS and all software updated.
- Exercise caution with emails, downloads, and links (as detailed in other guidelines).
- Use a firewall.
