TDM stands for text and data mining: the automated analysis of large volumes of digital content to find patterns, extract facts, or classify material. In cyber security, TDM is important because the same techniques used for legitimate analysis can also be used to mass-scan documents, logs, code, or web content for sensitive data, malware indicators, or training material. That makes access control, data labeling, and provenance tracking critical.
Defenders use TDM to process security telemetry, detect anomalies, and enrich threat intelligence at scale. Attackers use similar automation to scrape exposed files, enumerate targets, or build datasets for phishing and model training. In the EU, TDM also has a legal meaning: mining is generally allowed on lawfully accessible works unless rights are reserved. For security teams, the practical lesson is that machine-readable rules, audit trails, and reliable metadata matter because automated systems will act on whatever signal they can parse.