CVE-2022-23015 in BIG-IP
Summary
by MITRE • 01/25/2022
On BIG-IP versions 16.x before 16.1.0, 15.1.x before 15.1.4.1, and 14.1.2.6-14.1.4.4, when a Client SSL profile is configured on a virtual server with Client Certificate Authentication set to request/require and Session Ticket enabled and configured, processing SSL traffic can cause an increase in memory resource utilization. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
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Analysis
by VulDB Data Team • 01/28/2022
This vulnerability affects F5 BIG-IP appliances running specific versions where a memory exhaustion issue occurs during SSL traffic processing under particular configuration conditions. The flaw manifests when a Client SSL profile is configured with Client Certificate Authentication set to either request or require mode, combined with Session Ticket functionality enabled on a virtual server. The vulnerability represents a denial of service risk that can lead to system instability and service disruption. According to industry standards, this vulnerability aligns with CWE-400, which addresses unchecked resource consumption, and falls under the ATT&CK technique T1499.1 for resource exhaustion attacks. The memory utilization increase occurs specifically during SSL handshakes and subsequent traffic processing, making it particularly dangerous in high-traffic environments where the appliance handles numerous concurrent connections.
The technical root cause stems from improper memory management within the SSL processing pipeline when handling client certificates and session tickets simultaneously. When a client connects to a virtual server configured with these specific parameters, the system allocates memory resources to process the certificate exchange and session ticket operations. However, the memory cleanup mechanisms fail to properly release allocated resources after processing, leading to progressive memory accumulation over time. This memory leak behavior is exacerbated by the combination of certificate authentication requiring client certificates and session ticket functionality, which creates a complex interaction pattern that the memory management subsystem cannot handle efficiently. The vulnerability affects the SSL termination capabilities of the BIG-IP system, potentially causing the appliance to become unresponsive or crash entirely when memory consumption reaches critical levels.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential business continuity issues for organizations relying on F5 BIG-IP appliances for SSL termination and load balancing. In production environments, the memory exhaustion can occur gradually over time, making it difficult to detect until the system becomes critically unstable. Network administrators may observe performance degradation, connection timeouts, or complete service outages as the appliance consumes all available memory resources. The vulnerability affects organizations using legacy versions of BIG-IP software that have not been updated to supported releases, creating a significant risk for companies with outdated infrastructure or delayed patch management processes. The issue particularly impacts web applications, secure API gateways, and SSL-terminated services where client certificate authentication is required for enhanced security.
Organizations should implement immediate mitigations including upgrading to supported BIG-IP versions where this vulnerability has been addressed, specifically versions 16.1.0, 15.1.4.1, and 14.1.4.5 or later. Alternative temporary measures include disabling session tickets on virtual servers using client certificate authentication or configuring the system to use different SSL profile settings that avoid the problematic combination. Network security teams should monitor memory utilization metrics closely and implement automated alerting for memory consumption thresholds. The vulnerability demonstrates the importance of maintaining current software versions and following vendor security advisories, as unsupported versions become increasingly vulnerable to exploitation. Organizations should also consider implementing network segmentation and access controls to limit exposure, while ensuring that all security patches are applied according to established change management procedures. Compliance with industry standards such as NIST SP 800-53 and ISO 27001 requires maintaining up-to-date security configurations and addressing known vulnerabilities promptly to prevent potential exploitation by threat actors.