Cookie Bite Attack: Hijacking Sessions Through Stolen Cookies

A Cookie Bite attack is a form of session hijacking where cybercriminals steal authentication cookies from a user’s browser to impersonate them without needing credentials. These attacks often exploit insecure connections, poorly configured cookies, or browser vulnerabilities. Once an attacker obtains a valid session cookie, they can bypass login procedures—even MFA—and gain full access to the account until the session expires. Common delivery methods include man-in-the-middle attacks, XSS, and malware. To defend against Cookie Bite attacks, implement secure cookie flags (HttpOnly, Secure), use HTTPS, enforce session expiration policies, and monitor anomalies. Proactive security hardening is crucial for mitigating this threat.

“Cookie Bite” Entra ID Attack Exposes Microsoft 365

“Cookie Bite” Entra ID Attack Exposes Microsoft 365: A Critical Cloud Security Wake-Up Call

Ravi Jain
“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. ... Read More