Antivirus vs Data Stealing Malware

TL;DR

Yes, antivirus software can detect data stealing malware, but it’s not guaranteed. Modern malware uses tricks to avoid detection. Keeping your antivirus updated, being careful about what you click, and using extra security measures are important.

How Antivirus Software Works

1. Signature-based Detection: Antivirus software keeps a database of known malware ‘signatures’ (unique code patterns). When it scans your computer, it looks for these signatures.
2. Heuristic Analysis: This looks at how files behave. If something acts suspiciously – like trying to connect to unknown websites or modifying important system files – the antivirus might flag it as malicious even if it doesn’t recognise the signature.
3. Behavioural Monitoring: Similar to heuristics, but more focused on real-time actions. It watches what programs are doing as they run.

Why Data Stealing Malware Can Bypass Antivirus

1. New Malware: Brand new malware won’t be in any signature database yet. This is called a ‘zero-day’ threat.
2. Polymorphism: Malware can change its code slightly each time it infects a computer, making the signature different.
3. Obfuscation: Malware authors hide their code to make it harder for antivirus software to understand what it’s doing.
4. Encryption: Malware can encrypt parts of itself or the data it steals, so the antivirus doesn’t see anything suspicious until it decrypts it (which might be too late).
5. Living off the Land: Malware uses legitimate system tools (like PowerShell) to carry out its attacks. This makes it harder to distinguish from normal activity.

Steps to Improve Detection

1. Keep Your Antivirus Updated: This is crucial. Updates include the latest signatures and improved detection methods.
   • Most antivirus programs update automatically, but check your settings to be sure.
2. Run Regular Scans: Don’t just rely on real-time protection. Schedule full system scans at least once a week.
3. Be Careful What You Click: Phishing emails and malicious websites are common ways to deliver malware.
   • Don’t open attachments from unknown senders.
   • Hover over links before clicking to see where they lead.
   • Look for HTTPS in the address bar (the ‘s’ means it’s a secure connection).
4. Use a Firewall: A firewall blocks unauthorized access to your computer.
   • Windows has a built-in firewall. Make sure it’s enabled.
5. Enable Real-Time Protection: Ensure your antivirus is actively scanning files and websites in real-time.
6. Consider Additional Security Tools:
   • Anti-Malware Software: Programs like Malwarebytes can find threats that traditional antivirus might miss.
   • Endpoint Detection and Response (EDR): More advanced tools used by businesses, but some home versions are available. They provide deeper analysis of system activity.
7. Keep Your Operating System Updated: Updates often include security patches that fix vulnerabilities malware can exploit.
   • Windows: Go to Settings > Update & Security > Windows Update.

Checking if Your System is Compromised

1. Look for Unusual Activity: Slow performance, unexpected pop-ups, or changes to your homepage can be signs of infection.
2. Check Task Manager: Look for processes you don’t recognise.

   tasklist

3. Use a Scan Tool: Run a scan with your antivirus and an anti-malware program.