This isn't theoretical. The data is specific.
CrowdStrike's 2025 Global Threat Report found that 79% of detected intrusions in 2024 were malware-free. No malicious payload. No virus to match against a signature database. Attackers used stolen credentials, legitimate system tools, and hands-on-keyboard techniques to move through environments without ever triggering traditional antivirus.
Signature-based antivirus compares files against a known database of malware. If the file matches a known signature, it gets blocked. That works against commodity malware. It does nothing against an attacker who logs in with a stolen password, uses PowerShell to enumerate your network, and moves laterally to your design file server using tools that are already installed on every Windows machine.
For an electronics manufacturer, that attack path looks like this. A phishing email lands in an engineer's inbox. They click a link. The attacker gains access to the workstation. No malware is deployed. The attacker uses the engineer's legitimate credentials to access the design file server. They exfiltrate Gerber files, schematics, and BOM data over an encrypted connection. Antivirus never fires because there was nothing for it to detect.
EDR catches this. It monitors behavior, not just files. An unusual login pattern. A process that shouldn't be running. A large data transfer at 2 AM. Credential access from an unexpected location. These behavioral signals trigger detection and response, whether or not a malware signature exists.

