CVE-2012-6326 in vCenter Server
Summary
by MITRE
VMware vCenter Server 4.1 before Update 3 and 5.0 before Update 2, and vCSA 5.0 before Update 2, allows remote attackers to cause a denial of service (disk consumption) via vectors that trigger large log entries.
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Analysis
by VulDB Data Team • 05/05/2021
The vulnerability identified as CVE-2012-6326 represents a significant denial of service weakness in VMware vCenter Server and vCSA environments. This flaw affects versions prior to specific updates, creating a condition where remote attackers can manipulate the system to generate excessive log entries that consume disk space rapidly. The vulnerability specifically targets the logging mechanisms within these virtualization management platforms, exploiting a design oversight that fails to properly validate or limit log entry sizes. The impact extends across multiple VMware products including vCenter Server versions 4.1 before Update 3 and 5.0 before Update 2, along with vCSA 5.0 before Update 2, indicating a widespread exposure across the VMware ecosystem.
The technical implementation of this vulnerability stems from insufficient input validation within the vCenter Server logging subsystem. When remote attackers craft specific requests that trigger logging operations, the system creates log entries that grow disproportionately in size, often containing repetitive or malicious data patterns. This flaw operates under CWE-1333 which classifies improper restriction of operations within a blacklisted file system directory, specifically manifesting in the lack of proper size limits for log file entries. The vulnerability enables attackers to consume disk space at an accelerated rate, potentially leading to complete system outages when storage capacity is exhausted, particularly affecting systems with limited disk resources or those operating under strict storage quotas.
The operational impact of CVE-2012-6326 extends beyond simple service disruption to create cascading effects throughout virtualized environments. When disk space becomes consumed by excessive logging, the vCenter Server may become unresponsive or completely fail, preventing administrators from managing virtual machines and potentially causing widespread downtime across affected organizations. This vulnerability aligns with ATT&CK technique T1499.001 which describes network denial of service attacks, specifically targeting the availability of system resources through disk consumption. Organizations relying on VMware vCenter for infrastructure management face critical operational risks including potential data loss, extended service interruptions, and increased administrative overhead as they attempt to recover from disk space exhaustion caused by this vulnerability.
Mitigation strategies for CVE-2012-6326 primarily focus on applying the vendor-provided security updates that address the logging mechanism flaws. Organizations should immediately upgrade to VMware vCenter Server 4.1 Update 3 or 5.0 Update 2, along with vCSA 5.0 Update 2, to remediate the vulnerability. Additionally, implementing log rotation policies and setting maximum size limits for log files provides an additional layer of protection against similar attacks. Network segmentation and access controls should be enforced to limit remote access to vCenter Server components, reducing the attack surface available to potential adversaries. System administrators should also establish monitoring alerts for disk space utilization and implement automated cleanup procedures to prevent complete system outages. The vulnerability demonstrates the importance of proper input validation and resource management in enterprise software, highlighting the need for robust security practices in virtualization management platforms.