A leak market is a place where exposed data is posted, sold, or redistributed after a breach, theft, or accidental disclosure. These markets may exist on dark-web forums, messaging channels, or other hidden services, and the material can include documents, credentials, personal records, source code, or internal business files.
In cyber security, leak markets matter because they turn raw exposure into reusable criminal material. Once data is organized, attackers can search it for passwords, identity details, account numbers, or documents that support phishing, impersonation, fraud, and extortion. Defenders watch leak markets to assess risk, confirm whether sensitive data is circulating, and respond with account resets, fraud monitoring, takedowns, and customer alerts. A leak market is therefore not just a storage place: it is a distribution channel that increases the reach and value of stolen data.