Browser credential theft is the extraction of usernames, passwords, cookies, autofill data, or session tokens saved by a web browser. Infostealers commonly target browser profile files and local storage because many users let the browser remember logins for convenience. Once stolen, this material can let an attacker sign in without knowing the password, bypassing some MFA steps if a live session cookie is reused.
This technique matters because it often turns a single infected endpoint into broad account compromise. In real attacks, stealers search for Chromium- and Firefox-based browser data, then exfiltrate it to a command-and-control server or a criminal market. Defenders reduce risk by hardening endpoints, limiting saved credentials, using encrypted enterprise password managers, revoking active sessions after compromise, rotating passwords, and monitoring for unusual browser-profile access and token reuse.