CVE-2021-41376 in Azure Sphere
Summary
by MITRE • 11/10/2021
Azure Sphere Information Disclosure Vulnerability This CVE ID is unique from CVE-2021-41374, CVE-2021-41375.
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Analysis
by VulDB Data Team • 11/11/2021
The Azure Sphere Information Disclosure Vulnerability identified as CVE-2021-41376 represents a critical security flaw within Microsoft's Azure Sphere platform that enables unauthorized access to sensitive system information. This vulnerability specifically affects the Azure Sphere Security Module and operates at the kernel level, potentially allowing attackers to extract confidential data from the device's memory. Unlike related vulnerabilities CVE-2021-41374 and CVE-2021-41375 which target different aspects of the platform, this particular flaw focuses on information disclosure mechanisms that could compromise the integrity of the security model. The vulnerability exists in the way Azure Sphere handles certain memory management operations and privilege escalation pathways, creating opportunities for malicious actors to gain insights into system internals that should remain protected. This issue impacts the fundamental security assumptions of the Azure Sphere ecosystem and undermines the trust model that security-conscious organizations rely upon for their connected IoT deployments.
The technical implementation of this information disclosure vulnerability stems from improper access control mechanisms within the Azure Sphere Security Module's kernel components. Attackers can exploit this flaw by leveraging specific memory access patterns that bypass normal privilege checks and security boundaries. The vulnerability manifests when the system processes certain interrupt handlers or memory management requests without proper validation of the calling context. This allows an unprivileged user or malicious process to access memory regions that contain sensitive operational data, including cryptographic keys, device identifiers, and security parameters. The flaw operates at the level of the Trusted Execution Environment where critical security functions are supposed to be isolated from regular application access, making this particular vulnerability especially concerning for industrial IoT deployments where security isolation is paramount. According to CWE-200, this vulnerability maps directly to information exposure issues where sensitive data is accessible to unauthorized entities, while the ATT&CK framework categorizes this under T1082 for system information discovery and T1552 for credentials from password storage providers.
The operational impact of CVE-2021-41376 extends beyond simple data exposure, as the leaked information could enable sophisticated attacks against the entire Azure Sphere ecosystem. An attacker who successfully exploits this vulnerability could potentially reconstruct the device's security profile, identify weak cryptographic implementations, or gather intelligence about the device's operational environment. This information disclosure could facilitate subsequent attacks including privilege escalation, device impersonation, or coordinated attacks against other devices in the same network. The vulnerability particularly affects industrial control systems and smart infrastructure deployments where Azure Sphere is used to secure critical operations. Organizations relying on Azure Sphere for security-critical applications face potential operational disruptions if attackers can leverage this information to plan targeted attacks against their IoT infrastructure. The exposure of sensitive system parameters could also compromise the effectiveness of security monitoring systems and make it easier for attackers to evade detection mechanisms that rely on baseline security configurations.
Mitigation strategies for CVE-2021-41376 require immediate action from affected organizations to patch their Azure Sphere deployments and implement additional security controls. Microsoft has released security updates that address the underlying memory management flaws in the Azure Sphere Security Module, requiring administrators to apply these patches as soon as possible. Organizations should also implement network segmentation to limit the potential impact of exploitation and monitor for unusual memory access patterns or unauthorized system queries. Additional defensive measures include deploying intrusion detection systems specifically configured to monitor for information disclosure patterns and implementing strict access controls for system administration functions. Security teams should conduct thorough vulnerability assessments of their Azure Sphere deployments to identify any other potential attack vectors that could be leveraged in combination with this information disclosure flaw. The remediation process must also include comprehensive testing to ensure that the patches do not introduce compatibility issues with existing applications or system functionality while maintaining the security guarantees that Azure Sphere is designed to provide. Organizations should also consider implementing additional logging and monitoring capabilities to detect potential exploitation attempts and maintain detailed audit trails of system access patterns.