CVE-2019-6660 in BIG-IP
Summary
by MITRE
On BIG-IP 14.1.0-14.1.2, 14.0.0-14.0.1, and 13.1.0-13.1.1, undisclosed HTTP requests may consume excessive amounts of systems resources which may lead to a denial of service.
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Analysis
by VulDB Data Team • 02/23/2024
The vulnerability identified as CVE-2019-6660 affects F5 BIG-IP systems across multiple versions including 14.1.0-14.1.2, 14.0.0-14.0.1, and 13.1.0-13.1.1. This issue represents a significant security concern within the application delivery controller ecosystem, where improperly handled HTTP requests can lead to resource exhaustion and subsequent denial of service conditions. The vulnerability stems from the system's inadequate handling of certain HTTP request patterns that cause excessive consumption of system resources including memory and processing power. This flaw allows malicious actors to exploit the system's HTTP processing mechanisms to trigger resource depletion, ultimately resulting in service disruption for legitimate users. The vulnerability operates at the application layer and specifically targets the BIG-IP system's HTTP request handling capabilities, making it particularly dangerous in environments where continuous availability is critical.
The technical implementation of this vulnerability involves the exploitation of HTTP request parsing and processing logic within the BIG-IP system. When the system receives certain malformed or crafted HTTP requests, the processing routines fail to properly validate or limit resource consumption during request handling. This leads to a scenario where the system continuously allocates memory and processing resources to handle these requests without proper bounds or cleanup mechanisms. The flaw essentially creates a resource leak or consumption pattern that can be amplified through repeated or simultaneous requests, causing the system to exhaust available memory or CPU cycles. This behavior aligns with common denial of service attack patterns where resource exhaustion prevents legitimate operations from completing successfully. The vulnerability operates through the HTTP protocol layer and leverages the system's standard request processing pathways, making it particularly difficult to detect and prevent through conventional network monitoring approaches.
The operational impact of CVE-2019-6660 extends beyond simple service disruption to potentially compromise the entire availability and reliability of BIG-IP deployments. Organizations relying on these systems for critical network services may experience complete service outages that can affect thousands of users or applications depending on the deployment scale. The vulnerability's potential for remote exploitation means that attackers can trigger the denial of service condition without requiring physical access or local privileges, making it particularly dangerous in externally facing deployments. Network administrators may find that traditional monitoring and alerting systems fail to detect the gradual resource exhaustion that leads to service disruption, as the behavior may appear normal until the system reaches critical resource limits. The impact is compounded by the fact that the vulnerability affects multiple versions of the BIG-IP software, meaning that organizations with various system configurations across their network infrastructure may all be potentially vulnerable.
Mitigation strategies for CVE-2019-6660 should focus on both immediate defensive measures and long-term system hardening approaches. Organizations should prioritize applying the official F5 security patches and updates released to address this vulnerability, as these patches contain the necessary code modifications to properly handle HTTP request processing and prevent resource exhaustion. Network segmentation and access control measures should be implemented to limit exposure of vulnerable BIG-IP systems to untrusted networks and users. Implementing rate limiting and request validation mechanisms at the network perimeter can help prevent the exploitation of this vulnerability by limiting the volume and type of HTTP requests that reach the affected systems. Additionally, organizations should enhance their monitoring capabilities to detect unusual resource consumption patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of implementing robust input validation and resource management practices, aligning with security standards such as those outlined in the CWE database under categories related to resource management and input validation. Organizations should also consider implementing intrusion detection systems that can identify suspicious HTTP request patterns that may indicate exploitation attempts. The ATT&CK framework would classify this vulnerability under the 'Resource Exhaustion' tactic, where adversaries leverage system weaknesses to consume computational resources and achieve denial of service conditions. Regular vulnerability assessments and security testing should be conducted to ensure that similar vulnerabilities are identified and addressed before they can be exploited in operational environments.