CVE-2017-4922 in vCenter Server
Summary
by MITRE
VMware vCenter Server (6.5 prior to 6.5 U1) contains an information disclosure issue due to the service startup script using world writable directories as temporary storage for critical information. Successful exploitation of this issue may allow unprivileged host users to access certain critical information when the service gets restarted.
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Analysis
by VulDB Data Team • 01/06/2021
The vulnerability identified as CVE-2017-4922 represents a critical information disclosure flaw within VMware vCenter Server versions prior to 6.5 Update 1. This issue stems from improper privilege management in the service startup script execution process, where the system utilizes world-writable directories for temporary storage of sensitive critical information. The fundamental flaw lies in the design decision to employ directories with unrestricted write permissions for storing confidential data during service initialization, creating an exploitable vector for unauthorized information access.
The technical implementation of this vulnerability exploits the principle of least privilege violation by allowing any user account on the host system to write to directories that are subsequently used by the vCenter service for temporary storage operations. When the vCenter service restarts, these temporary files containing sensitive information remain accessible to all users who possess write permissions to the affected directories. This design flaw creates a window of opportunity where malicious or unauthorized users can potentially extract critical system information, configuration details, or authentication data that should remain restricted to privileged administrators only.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to gain insights into the internal structure and configuration of the vCenter environment. The vulnerability affects the integrity of the security model by undermining the trust boundary between different user accounts on the same host system, potentially allowing attackers to escalate their privileges or conduct further reconnaissance activities. This issue particularly impacts organizations relying on VMware vCenter Server for virtual infrastructure management, as it compromises the confidentiality of sensitive operational data and may facilitate more sophisticated attacks.
Organizations should implement immediate mitigations including upgrading to VMware vCenter Server 6.5 Update 1 or later versions where this vulnerability has been addressed through proper directory permission controls and secure temporary file handling mechanisms. The fix involves ensuring that temporary storage directories used by the service startup script are configured with appropriate access controls that prevent unauthorized write access from non-privileged accounts. Additionally, security administrators should review and harden directory permissions throughout the system, implementing the principle of least privilege for all temporary storage locations and monitoring for unauthorized access attempts to sensitive system areas. This vulnerability aligns with CWE-732, which addresses inadequate permissions for critical resources, and represents a significant concern for organizations following ATT&CK framework's privilege escalation and credential access tactics.