CVE-2022-31698: VMware Cloud Foundation DoS Vulnerability

CVE-2022-31698 Overview

CVE-2022-31698 is a denial-of-service vulnerability affecting the content library service in VMware vCenter Server. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to trigger a denial-of-service condition by sending a specially crafted header. This vulnerability poses a risk to organizations relying on vCenter Server for managing virtualized infrastructure, as successful exploitation could disrupt critical management operations.

Critical Impact

Attackers can remotely trigger a denial-of-service condition against vCenter Server's content library service, potentially disrupting virtual machine template management, library synchronization, and overall infrastructure administration without requiring authentication.

Affected Products

• VMware vCenter Server versions 6.5, 6.7, and 7.0 (including various updates and patches)
• VMware Cloud Foundation versions 3.x (3.0 through 3.11)
• VMware Cloud Foundation versions 4.x (4.0 through 4.4.1.1)

Discovery Timeline

• December 13, 2022 - CVE-2022-31698 published to NVD
• October 31, 2025 - Last updated in NVD database

Technical Details for CVE-2022-31698

Vulnerability Analysis

This denial-of-service vulnerability resides in the content library service of VMware vCenter Server. The content library service provides a centralized repository for storing and managing VM templates, ISO images, and other files across multiple vCenter Server instances. The vulnerability is triggered when the service processes network requests containing specially crafted HTTP headers.

The vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption), indicating that the content library service fails to properly handle or limit resource consumption when processing malicious input. This allows an attacker to exhaust server resources or cause the service to become unresponsive, effectively denying legitimate users access to content library functionality.

Root Cause

The root cause of this vulnerability lies in improper input validation within the content library service's header parsing mechanism. When the service receives HTTP requests on port 443, it processes header values without adequate validation or resource constraints. A specially crafted header can cause the service to enter a state where it consumes excessive resources or encounters an error condition that leads to service disruption.

Attack Vector

The attack can be executed remotely over the network by any actor who can reach port 443 on the vCenter Server. The exploitation does not require authentication, prior access to the system, or user interaction. An attacker simply needs to send a malformed HTTP request with a specially crafted header to the content library service endpoint.

The attack flow consists of:

1. Attacker identifies a vCenter Server with port 443 exposed
2. Attacker crafts a malicious HTTP request containing a specially formatted header
3. The request is sent to the content library service endpoint
4. The service processes the malformed header improperly
5. Resource exhaustion or service disruption occurs, resulting in denial of service

Detection Methods for CVE-2022-31698

Indicators of Compromise

• Unexpected vCenter Server content library service crashes or restarts
• Anomalous HTTP traffic patterns targeting port 443 with unusual header characteristics
• Elevated resource consumption (CPU/memory) on the vCenter Server prior to service disruption
• Log entries indicating content library service failures or exceptions during header processing

Detection Strategies

• Monitor vCenter Server logs for content library service errors, particularly those related to request processing or header parsing
• Implement network-level anomaly detection to identify malformed HTTP requests targeting vCenter Server port 443
• Deploy intrusion detection signatures that look for abnormal header patterns in requests to vCenter infrastructure
• Use VMware's health monitoring tools to track content library service availability and performance

Monitoring Recommendations

• Enable verbose logging on vCenter Server services to capture detailed information about incoming requests
• Configure alerting for content library service availability drops or unexpected restarts
• Implement baseline monitoring for network traffic to vCenter Server and alert on deviations
• Use SentinelOne Singularity platform to monitor endpoint behavior on systems hosting vCenter Server for signs of exploitation attempts

How to Mitigate CVE-2022-31698

Immediate Actions Required

• Apply VMware security patches as outlined in VMware Security Advisory VMSA-2022-0030
• Restrict network access to vCenter Server port 443 to only trusted management networks and administrators
• Review firewall rules to ensure vCenter Server is not unnecessarily exposed to untrusted networks
• Monitor vCenter Server for signs of exploitation attempts while patches are being applied

Patch Information

VMware has released security updates to address this vulnerability. Administrators should consult the VMware Security Advisory VMSA-2022-0030 for detailed patching instructions and the specific fixed versions for their deployment. Additional technical analysis is available in the Talos Intelligence Vulnerability Report.

For vCenter Server:

• Version 7.0: Apply the appropriate Update 3 patch or later
• Version 6.7: Apply the appropriate Update 3 patch or later
• Version 6.5: Apply the appropriate Update 3 patch or later

For VMware Cloud Foundation:

• Follow KB article guidance provided in VMSA-2022-0030 for your specific version

Workarounds

• Implement network segmentation to limit access to vCenter Server from untrusted networks
• Use a web application firewall (WAF) or reverse proxy to inspect and filter incoming requests to vCenter Server
• Consider temporary service isolation if immediate patching is not possible and the environment is at high risk
• Deploy network access controls to restrict port 443 access to authorized management workstations only

# Example: Restrict vCenter access using iptables on a perimeter firewall
# Allow only trusted management network to access vCenter port 443
iptables -A INPUT -p tcp --dport 443 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP