Open, Closed and Commercial Intelligence Sources

A mature threat intelligence program combines three complementary types of sources: open sources, such as public forums, social networks and independent researchers' reports; closed sources, such as trusted communities among sector peers or exchanges with government agencies; and commercial sources, paid feeds with curated indicators and additional context produced by specialized vendors. In practice, no category is enough on its own: open sources are free but require a lot of curation and verification effort, commercial ones offer quality and speed but at a cost not every organization can sustain, and closed ones provide unique context about threats targeting the specific sector that rarely appears in public sources. A common mistake is relying exclusively on commercial feeds assuming they cover the whole relevant landscape, when in reality emerging threats or those targeting specific niches are often discussed first in closed communities or specialized forums before appearing in any established commercial feed. Diversifying sources and checking the overlap between them significantly improves the program's real coverage.