Cookie Bite Attack: Microsoft 365 Session Hijacking
The source describes the “Cookie Bite” attack, a novel method where malicious browser extensions steal authentication cookies like ESTSAUTH and ESTSAUTHPERSISTENT from users of Microsoft 365 and Azure Entra ID. By leveraging these cookies, attackers can bypass Multi-Factor Authentication (MFA) and hijack legitimate sessions, gaining unauthorized access to services like Outlook, Teams, and SharePoint. This attack is particularly dangerous because it operates within the browser and does not require system-level compromise, making it difficult to detect through traditional security measures. The article highlights the risks of this attack, including data exfiltration and internal impersonation, and outlines mitigation strategies such as monitoring risk-based sign-ins, implementing browser-level protections, and limiting session persistence. It also introduces Technijian’s security services as a solution to protect against this and similar threats.
