When “Enabling MFA” Isn’t Enough

Multi-factor authentication (MFA) has become a popular security measure for protecting sensitive enterprise information. And while any implementation of MFA is better than none, many customers we talk to realize that MFA is not always enabled as it should be, but not all MFA methods are created equal.

Despite its security benefits, MFA implementation alone can still be vulnerable to session token interception, where a threat actor gains unauthorized access to a user's session token and then uses it to impersonate the user and access protected information. The impact of this type of incident on enterprise security is significant, and organizations must have effective threat mitigation strategies in place to detect and prevent such incidents.

Understanding MFA Session Token Interception Techniques

Session token interception is a cyberattack technique employed by threat actors to gain unauthorized access to a user's session token, which is used to authenticate system users. By intercepting a legitimate MFA session token, the attacker can leverage the stolen session token to cause the following incidents:

●      Man-in-the-middle (MitM) incidents: Threat actors intercept communication between a user and a system, allowing them to access and steal the session token.

●      Session hijacking: A threat actor can hijack a user's session by intercepting the session token, usually stored in a cookie, and using it to access the system as the user.

●      Session prediction: In a session prediction incident, threat actors use information about the system's session token generation process to predict a valid session token and access the system.

Understanding the Impact of MFA Session Token Interception

The rapidly evolving nature of today’s cyber threat landscape requires proactive threat mitigation strategies to maintain resilience. As a result, security controls deployed last year may not be adequate to defend against tomorrow’s threats: traditional security measures, such as firewalls (host-based or network-based) or antivirus offerings, may not be enough to protect against MFA session token interception.

The impact of MFA session token interception on an organization's cybersecurity posture can be significant, particularly regarding systems confidentiality, integrity, availability, and privacy. If successful, threat actors can leverage token interceptions to access the system and sensitive information.  Unfortunately, they may be undetected for an extended period, exacerbating the attack’s impact.

A successful MFA session token interception incident can undermine the confidence of users and customers, potentially damaging an organization’s reputation and leading to business losses. Thus, impacting the legal and regulatory threshold surrounding security and privacy standards and regulations could lead to violating laws and legal consequences for the organization.

Below are some ways an MFA session token interception attack can impact an organization’s threat mitigation strategies and overall security posture:

●      Increased risk of data breaches: Unauthorized access to sensitive information increases the risk of data breaches, which can have severe consequences for the organization and its clients or customers.

●      Decreased trust: The interception of an MFA session token could erode the trust of clients and customers in the organization, leading to loss of business and incurring reputational damage.

●      Costly remediation: The organization may need to spend significant resources to remediate the attack’s consequences, including rebuilding and restoring systems.

Organizations must consider implementing proactive threat mitigation strategies, such as regularly reviewing their network for vulnerabilities and conducting penetration testing to identify potential weaknesses. In addition, ensuring that employees receive regular security awareness training contributes to a resilient security posture.

Further Securing Your Enterprise

Mitigating the risk of MFA session token interception requires a multi-layered approach. To do so, encrypting communications between users and systems is critical - this prevents threat actors from easily eavesdropping on sensitive information. Additionally, organizations can implement secure communication protocols by deploying SSL/TLS encryption protocols - deploying TLS 1.3 for end-to-end encryption of web sessions is highly recommended, but specifically blocking TLS 1.0/1.1 is a great start.

In most organizations, the SSL/TLS conversation revolves around legacy applications and is separate. If that applies to your organization, then implementing session management controls, such as session timeouts and management logs, will help to detect and prevent session token interception on an operational security basis. Session timeouts, for example, can automatically log a user out of a system after a specified period of inactivity and reduce the risk of session hijacking.

Adding hard tokens / PAW for users with sensitive roles and responsibilities is a small expense and is worthy of a conversation. Still, ironically administrator accounts are typically last to have an extra layer of security added, especially in outsourced environments.

From an identity access management (IAM) and computing perspective, deploying the most secure MFA authentication via Microsoft’s Authenticator app vs. text message, and if possible, deploying Windows Hello for Business (WHfB) adds an extra layer of security against session token interception.

Are you looking to assess your organization’s risk exposure to MFA session token interception or unsure where to start? Schedule some time to discuss!