CVE-2017-4927 in vCenter Server
Summary
by MITRE
VMware vCenter Server (6.5 prior to 6.5 U1 and 6.0 prior to 6.0 U3c) does not correctly handle specially crafted LDAP network packets which may allow for remote denial of service.
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Analysis
by VulDB Data Team • 01/24/2021
The vulnerability identified as CVE-2017-4927 affects VMware vCenter Server versions prior to 6.5 U1 and 6.0 U3c, representing a critical remote denial of service flaw within the LDAP handling mechanisms of the platform. This issue stems from the improper processing of specially crafted LDAP network packets that can be transmitted over the network to the vulnerable vCenter Server instances. The flaw exists in the server's ability to validate and process incoming LDAP requests, creating an avenue for malicious actors to disrupt normal service operations without requiring authentication credentials.
The technical nature of this vulnerability places it within the scope of CWE-129, which addresses improper validation of input boundaries, and CWE-400, which covers the potential for denial of service attacks through resource exhaustion. The vulnerability manifests when the vCenter Server receives malformed LDAP packets that trigger unexpected behavior in the underlying LDAP processing libraries. These packets are specifically crafted to exploit buffer handling mechanisms or memory allocation routines within the LDAP implementation, causing the server to either crash or become unresponsive to legitimate requests. The flaw operates at the network protocol level, making it particularly dangerous as it can be exploited from external networks without requiring privileged access to the system.
From an operational impact perspective, this vulnerability poses significant risk to enterprise environments that rely on VMware vCenter Server for virtual infrastructure management. The denial of service condition can result in complete unavailability of the vCenter Server service, effectively disabling critical management functions for virtual machines, resource pools, and cluster configurations. This disruption can cascade throughout the datacenter, as administrators lose the ability to monitor, control, or modify virtual environments, potentially affecting business continuity and disaster recovery operations. The impact extends beyond immediate service disruption to include potential financial losses from extended downtime and the operational burden of emergency response procedures.
Organizations should implement immediate mitigations including applying the vendor-provided patches for VMware vCenter Server 6.5 U1 and 6.0 U3c releases, which address the LDAP handling flaws through proper input validation and buffer management. Network segmentation strategies should be employed to limit exposure of vCenter Server instances to untrusted networks, while implementing intrusion detection systems to monitor for suspicious LDAP traffic patterns. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for network denial of service attacks, emphasizing the need for network-level protections. Additionally, organizations should conduct thorough vulnerability assessments to identify any other potentially affected systems and implement monitoring solutions that can detect abnormal LDAP traffic behavior, as the vulnerability can be leveraged for both intentional disruption and as a reconnaissance tool for more sophisticated attacks.