Identity is no longer enough: continuous verification of the device for real-time security

Identity remains the backbone of many security architectures, but today that column is cracking under new pressures: advanced phishing, real-time proxyan authentication kits and dispersed work models that multiply risk vectors. A username and password, even validated with MFA, no longer guarantee on their own that the connection is secure.

The problem is not only that authentication fails, but that the signals that validate a session are rarely reassessed during their useful life. A session token issued after overcoming MFA can be intercepted and reused by an attacker; from the service perspective, that token is indistinguishable from the legitimate one. This is why the Zero Trust framework proposed by institutions such as NIST also recommends assessing the position of the device when making access decisions: NIST SP 800-207.

In practice, many organizations remain in the timely validation: verified identity, MFA OK and session started until the end of the token. This approach leaves a post-authentication blind area where changes in endpoint - deactivation of antivirus control, pending patches, unauthorized hardware - can turn an initially legitimate session into an entry door for the attacker.

The empirical evidence reinforces the urgency: incident reports continue to point to stolen credentials as a key factor in a significant proportion of gaps. Verizon, in his annual report, shows how identity abuse continues to dominate the attack surface and why it is necessary to complement identity verification with real-time contextual controls: Verizon DBIR.

The practical solution that goes beyond timely verification is to unite identity and health of the device in continuous access decisions. Continuous verification of the device requires access to depend not only on who is authenticated, but on what is authenticated and in what operational status this device is. Technologies such as continuous access assessment (Continuous Access Evaluation) allow you to revoke or adjust privileges while the session is active: more about CAE.

This has specific implications for security teams: access policies must be able to distinguish between a managed corporate endpoint and a personal or committed endpoint, must integrate EDR / MDM signals with the identity system, and must apply proportional controls that avoid unnecessary blocks without giving up security. Attacking this problem requires integration between identity and endpoint, as well as automation to react in real time.

Not everything is technological: there are operational costs and challenges. Continuous monitoring of device status raises privacy / legal concerns in BYOD environments and requires clear consent processes and telemetry limits. In addition, many legacy applications do not support modern session control mechanisms, which requires hybrid strategies that include network segmentation, microsegmentation and reduced use of unsafe protocols.

For security teams that need to prioritize actions today, practical recommendations include inventing critical applications and their access vectors, deploying continuous testing pilot tests in a controlled subset of users, requiring phishing-resistant authenticators (FIDO2 / WebAuthn) where possible, shortening the life of privileged tokens and connecting EDR / MDM signals to the access decision engine to enable automated responses to endpoint position degradation.

In short, identity is still necessary but no longer sufficient. Modern defense requires that the decision to allow or limit access combine who, how and from what the user is connected, and that that decision be reevaluated throughout the session. Those who adopt a model that integrates identity and continuous verification of the device will significantly reduce the operational value of stolen credentials and intercepted tokens, making life difficult for professional attackers.