Account takeover (ATO) is a fraudulent activity where cybercriminals gain unauthorized access to a person’s or organization’s online account, often by stealing login credentials. Once the attacker has control, they can manipulate the account for various malicious purposes, including identity theft, financial fraud, or unauthorized transactions. ATOs can occur through various methods, such as phishing, credential stuffing, or malware attacks. To combat ATO, individuals and businesses should practice strong password management, enable multi-factor authentication, and regularly monitor their accounts for suspicious activity.