CVE-2017-9214 in vSwitch
Summary
by MITRE
In Open vSwitch (OvS) 2.7.0, while parsing an OFPT_QUEUE_GET_CONFIG_REPLY type OFP 1.0 message, there is a buffer over-read that is caused by an unsigned integer underflow in the function `ofputil_pull_queue_get_config_reply10` in `lib/ofp-util.c`.
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Analysis
by VulDB Data Team • 12/07/2022
The vulnerability CVE-2017-9214 represents a critical buffer over-read flaw in Open vSwitch version 2.7.0 that occurs during the processing of OpenFlow protocol messages. This issue specifically manifests when handling OFPT_QUEUE_GET_CONFIG_REPLY type messages within the OpenFlow Protocol version 1.0 implementation. The vulnerability resides in the `ofputil_pull_queue_get_config_reply10` function located in the `lib/ofp-util.c` source file, making it a core component of the network virtualization infrastructure that powers many cloud and data center environments.
The technical root cause of this vulnerability stems from an unsigned integer underflow condition that occurs during message parsing operations. When the function processes incoming queue configuration replies, it fails to properly validate the length parameters of the incoming message data structure. This improper validation allows an attacker to craft malicious OpenFlow messages that cause the unsigned integer to underflow, resulting in a buffer over-read condition where the program attempts to access memory locations beyond the allocated buffer boundaries. This type of vulnerability falls under CWE-129, which specifically addresses insufficient input validation leading to buffer overflows, and more broadly under CWE-191, which covers integer underflow conditions.
The operational impact of this vulnerability is significant for any system running Open vSwitch 2.7.0 that processes untrusted OpenFlow messages from external sources. An attacker who can inject malicious OpenFlow protocol messages into the network infrastructure could potentially exploit this buffer over-read to execute arbitrary code on the affected system, leading to complete system compromise. The vulnerability is particularly dangerous in cloud environments where Open vSwitch serves as a critical networking component for virtual machine communication, as it could enable attackers to gain unauthorized access to virtualized network resources and potentially escalate privileges within the network infrastructure. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where the buffer over-read could be leveraged to execute malicious code in the context of the running Open vSwitch process.
Mitigation strategies for CVE-2017-9214 should prioritize immediate patching of affected Open vSwitch installations to version 2.7.1 or later, which contains the necessary fixes for the integer underflow condition. Network administrators should also implement network segmentation and access controls to limit exposure to untrusted OpenFlow message sources, as well as deploy intrusion detection systems that can monitor for suspicious OpenFlow protocol traffic patterns. Additionally, organizations should conduct thorough vulnerability assessments of their network infrastructure to identify any other systems that might be running vulnerable versions of Open vSwitch, particularly those that process external OpenFlow messages from network devices or virtualization platforms. The fix implemented in the patched versions involves proper validation of message length parameters before buffer operations, preventing the unsigned integer underflow condition that led to the buffer over-read scenario.