Katz Stealer: The Silent Thief Lurking in Trusted Apps

Katz Stealer is a stealthy, malware-as-a-service threat that surfaced in 2025, designed to make credential theft easy and effective even for unskilled attackers. Delivered through phishing emails and fake software, it silently infiltrates systems, using clever tricks like hiding code in images, exploiting trusted tools like MSBuild and cmstp.exe, and hijacking apps like Discord to stay hidden and maintain access. Once active, it targets browsers to steal passwords, cookies, tokens, credit card details, and even crypto wallets, decrypting sensitive data by mimicking legitimate browser behavior. Its reach spans email, VPNs, FTPs, gaming accounts, and over 150 crypto wallet extensions, all exfiltrated via encrypted channels to attacker-controlled servers.