CVE-2021-22008 in vCenter Server
Summary
by MITRE • 09/24/2021
The vCenter Server contains an information disclosure vulnerability in VAPI (vCenter API) service. A malicious actor with network access to port 443 on vCenter Server may exploit this issue by sending a specially crafted json-rpc message to gain access to sensitive information.
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Analysis
by VulDB Data Team • 10/02/2021
The CVE-2021-22008 vulnerability represents a critical information disclosure flaw within VMware vCenter Server's VAPI (vCenter API) service architecture. This vulnerability resides in the server's handling of JSON-RPC messages, specifically within the API service layer that manages communication between vCenter Server and various client applications. The flaw allows unauthorized access to sensitive system information through a crafted JSON-RPC request sent over the standard HTTPS port 443, making it particularly dangerous as it operates over the default secure communication channel that organizations typically expect to be protected. The vulnerability affects VMware vCenter Server versions prior to 7.0 U1c, 6.7 U3k, and 6.5 U3n, representing a significant security gap in enterprise virtualization management platforms.
The technical implementation of this vulnerability stems from insufficient input validation and access control mechanisms within the VAPI service. When a malicious actor sends a specially crafted JSON-RPC message to the vCenter Server's API endpoint, the system fails to properly validate the request parameters and authorization context. This allows the attacker to bypass normal access controls and retrieve sensitive information that should be restricted to authorized administrators only. The vulnerability can be exploited remotely without requiring authentication, making it particularly dangerous in environments where vCenter Server is accessible from untrusted networks. The flaw specifically impacts how the VAPI service processes certain API calls, allowing for information leakage through improper response handling that reveals internal system details, configuration information, and potentially credentials or session tokens.
The operational impact of CVE-2021-22008 extends beyond simple information disclosure, as the leaked data could enable more sophisticated attacks within the virtualized environment. Attackers who successfully exploit this vulnerability can gain insights into the vCenter Server's internal architecture, including system configurations, network topology information, and potentially administrative credentials or session management details. This reconnaissance capability significantly increases the risk of subsequent attacks, as adversaries can use the disclosed information to plan more targeted exploitation attempts against other components within the VMware infrastructure. The vulnerability creates a persistent threat vector that remains active as long as affected systems are operational, potentially allowing attackers to establish long-term reconnaissance capabilities within enterprise environments. Organizations utilizing vCenter Server in production environments face increased risk of supply chain attacks, lateral movement, and privilege escalation attempts when this vulnerability remains unpatched.
Mitigation strategies for CVE-2021-22008 focus primarily on immediate patch deployment and network segmentation measures. VMware has released security patches for all affected versions including 7.0 U1c, 6.7 U3k, and 6.5 U3n, which address the input validation and access control flaws within the VAPI service. Organizations should prioritize patching their vCenter Server installations as soon as possible, following VMware's recommended upgrade procedures to ensure complete remediation. Network-level mitigations include implementing firewall rules to restrict access to port 443 on vCenter Server to only trusted administrative networks and IP addresses. The use of network monitoring tools to detect unusual JSON-RPC traffic patterns can help identify potential exploitation attempts. Additionally, organizations should conduct thorough security assessments of their vCenter Server configurations, reviewing access controls and implementing principle of least privilege for API users. From a compliance perspective, this vulnerability aligns with CWE-200 (Information Disclosure) and represents a significant concern under NIST SP 800-53 security controls, particularly those related to access control and system monitoring. The vulnerability also maps to ATT&CK technique T1087.001 (Account Discovery) and T1566 (Phishing) as attackers may use the disclosed information to conduct more sophisticated social engineering campaigns targeting vCenter administrators.