The circulation of such lists facilitates several types of cyberattacks:

To mitigate the risk of such leaks, security teams should implement: Use MailItemsAccessed to investigate compromised accounts

: Compromised accounts can be used to send fraudulent invoices or "spearphishing" emails to coworkers, appearing as a trusted colleague.

: Attackers gain full access to private communications, contacts, and sensitive documents.

: Since many users reuse passwords, these "valid" mail credentials may also grant access to the user's financial or social media accounts. Remediation & Defense

: Credential pairs (Email/Password) often formatted as email:password .