Most infostealer infections happen on unmanaged or personal devices — outside the visibility of antivirus, EDR, or SIEM. Once credentials and session tokens are stolen, they’re quietly uploaded to criminal marketplaces and Telegram channels.

These “logs” are often sold within hours. Each one may include:

• Credentials for corporate email, VPNs, and admin tools

• Live session tokens that bypass MFA

• IP addresses, OS versions, and browser metadata

• Sensitive local files or documents

• URLs and cookies tied to internal systems

Since the infection typically happens off-network, the most effective way to detect it is by monitoring stealer marketplaces directly — before attackers act on the stolen access.

Passguard continuously monitors active infostealer markets and leak channels. If logs tied to your domains or internal tools appear, you’re alerted — even if the infection originated from a device you don’t control.