Infostealer logs have evolved from an underground commodity into an operational security problem. For defenders, finding an exposed credential is only the beginning. In today’s reality many security analysts start their morning with an alert: an employee’s corporate email address has appeared in a newly collected infostealer log.
The log contains a username and password for a corporate SaaS application. There are browser cookies, meaning live sessions that can be exploited, and several other saved, in files, credentials.
A personal employee computer got infected by Vidar located hundreds of miles from the company’s offices. Now what?
Resetting the exposed password seems obvious. But that may not solve the problem. If the stealer captured an authenticated session cookie, an attacker may already have a way into the application without needing the password or another MFA prompt. If the employee reused corporate credentials on a personal computer, the endpoint that created the exposure may not even be managed by the organization.
And somewhere in an underground Telegram channel, the same information may already be available to an initial access broker, ransomware affiliate, or opportunistic attacker.
