OSINT (open-source intelligence)
open-source intelligence · open source intelligence · passive reconnaissance · public-source intelligence · renseignement en sources ouvertes
Collecting and analysing publicly available information (websites, social media, public registers, published leaks) to understand a target.
In practice
Attackers almost always start here: organisation charts, email address formats, suppliers, software named in job ads, photos of badges posted online. These details make spear phishing or CEO fraud highly convincing. Defenders, journalists and investigators use the same methods, quite lawfully, to measure an organisation’s exposure. Running the exercise on your own company regularly is one of the cheapest security measures there is.
Fictional case: in one hour, an auditor rebuilds a mid-sized company’s finance team from public professional profiles, guesses the email format from a press release and spots, in a job ad, the name of the accounting software in use. Enough to write a very convincing fake supplier email.
How to protect yourself
- Have what the company and its staff expose online audited regularly, and remove what is not needed (detailed org charts, software versions, photos of badges).
- Require two-person approval for any change of bank details or unusual transfer.
- Monitor credential leaks under the company’s name and force a reset of exposed passwords.
