CVE-2017-14970 in vSwitch
Summary
by MITRE
In lib/ofp-util.c in Open vSwitch (OvS) before 2.8.1, there are multiple memory leaks while parsing malformed OpenFlow group mod messages.
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Analysis
by VulDB Data Team • 12/30/2022
The vulnerability identified as CVE-2017-14970 resides within the Open vSwitch implementation, specifically in the lib/ofp-util.c file where the OpenFlow protocol parsing logic handles group modification messages. This issue affects versions prior to 2.8.1 and represents a critical memory management flaw that can lead to resource exhaustion and system instability. The vulnerability manifests when the system processes malformed OpenFlow group mod messages, which are part of the OpenFlow protocol used for communication between network switches and controllers in software-defined networking environments.
The technical flaw stems from inadequate memory deallocation practices during the parsing of malformed OpenFlow group mod messages. When these messages contain unexpected or corrupted data structures, the parsing functions fail to properly release allocated memory resources, resulting in multiple memory leaks throughout the processing flow. This memory leak pattern occurs because the code does not implement proper error handling and cleanup mechanisms for malformed input data. The vulnerability is particularly concerning as it operates at the protocol parsing layer where untrusted input from network peers is processed, making it susceptible to exploitation through crafted malicious OpenFlow messages. According to CWE classification, this maps to CWE-401: Improper Release of Memory and CWE-772: Missing Release of Resource after Effective Lifetime, both of which are fundamental memory management issues that can lead to denial of service conditions.
The operational impact of this vulnerability extends beyond simple resource consumption, as it creates persistent memory leaks that can accumulate over time and eventually lead to complete system exhaustion. In production Open vSwitch deployments, this vulnerability can be exploited by attackers who send malformed group mod messages to network switches or controllers, causing progressive memory degradation that may result in system crashes or complete service unavailability. The vulnerability affects both the controller and switch components of Open vSwitch, making it particularly dangerous in large-scale software-defined networking environments where multiple devices communicate through the OpenFlow protocol. From an ATT&CK perspective, this vulnerability aligns with T1499.004: Endpoint Denial of Service and T1068: Exploitation for Privilege Escalation, as it can be leveraged to create persistent denial of service conditions that compromise network availability and potentially provide a foothold for further exploitation.
Mitigation strategies for CVE-2017-14970 primarily focus on upgrading to Open vSwitch version 2.8.1 or later, which contains the necessary patches to address the memory leak conditions. Organizations should also implement network segmentation and access controls to limit exposure to untrusted OpenFlow peers, while monitoring for unusual memory consumption patterns that might indicate exploitation attempts. Additional defensive measures include implementing rate limiting on OpenFlow message processing and deploying intrusion detection systems that can identify malformed OpenFlow traffic patterns. The vulnerability highlights the importance of proper resource management in network protocol implementations and underscores the need for comprehensive testing of error handling paths in security-critical network components. Organizations should also conduct regular vulnerability assessments of their Open vSwitch deployments to identify and remediate similar memory management issues that may exist in other protocol parsing components.