CVE-2021-22011 in vCenter Server
Summary
by MITRE • 09/24/2021
vCenter Server contains an unauthenticated API endpoint vulnerability in vCenter Server Content Library. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to perform unauthenticated VM network setting manipulation.
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Analysis
by VulDB Data Team • 10/02/2021
The vulnerability identified as CVE-2021-22011 represents a critical security flaw within VMware vCenter Server's Content Library functionality that exposes organizations to significant operational risks. This issue stems from an improperly secured API endpoint that allows unauthorized access without requiring authentication credentials, creating a pathway for malicious actors to manipulate virtual machine network configurations. The vulnerability specifically affects the Content Library component of vCenter Server, which serves as a centralized repository for virtual machine templates, ISO images, and other virtualization assets. Attackers can exploit this weakness by connecting directly to port 443 on the vCenter Server instance, bypassing normal authentication mechanisms and gaining access to sensitive virtualization management functions.
The technical nature of this vulnerability aligns with CWE-284, which addresses improper access control issues in software systems. This flaw enables an attacker to perform unauthorized operations on virtual machine network settings through an unauthenticated API endpoint, potentially allowing for network reconnaissance, lateral movement, or disruption of virtualized environments. The vulnerability's impact extends beyond simple network manipulation as it provides attackers with the ability to alter virtual machine configurations, potentially compromising the integrity and availability of the entire virtual infrastructure. The Content Library's API endpoint failure to properly validate authentication status creates an attack surface that can be exploited by threat actors with basic network connectivity to the vCenter Server.
From an operational perspective, this vulnerability poses severe risks to organizations relying on VMware vCenter Server for their virtualization infrastructure management. The ability to manipulate VM network settings without authentication can enable attackers to redirect traffic, establish backdoors, or disrupt network communications within the virtual environment. This capability directly maps to several techniques documented in the MITRE ATT&CK framework under the T1059 and T1046 categories, which cover execution through remote services and network service scanning respectively. Organizations may experience cascading effects from this vulnerability, including potential data exfiltration, service disruption, or compromise of downstream systems that depend on the affected virtual machines.
The security implications of CVE-2021-22011 extend to compliance and regulatory requirements that mandate proper access controls and network segmentation within virtualized environments. Organizations utilizing vCenter Server must implement immediate mitigations including network segmentation to restrict access to port 443, deployment of firewalls to limit external exposure, and application of VMware's official security patches. Additionally, organizations should conduct comprehensive network monitoring to detect unauthorized access attempts and implement proper network access controls to prevent lateral movement. The vulnerability demonstrates the critical importance of maintaining up-to-date security configurations and proper network segmentation practices to prevent unauthorized access to privileged management interfaces. Regular security assessments and vulnerability scanning should be implemented to identify similar unauthenticated access points within the virtualization infrastructure, ensuring comprehensive protection against similar attack vectors.