CVE-2016-2074 in vSwitch
Summary
by MITRE
Buffer overflow in lib/flow.c in ovs-vswitchd in Open vSwitch 2.2.x and 2.3.x before 2.3.3 and 2.4.x before 2.4.1 allows remote attackers to execute arbitrary code via crafted MPLS packets, as demonstrated by a long string in an ovs-appctl command.
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Analysis
by VulDB Data Team • 08/26/2022
The vulnerability identified as CVE-2016-2074 represents a critical buffer overflow flaw within the Open vSwitch software ecosystem, specifically affecting versions 2.2.x through 2.3.2 and 2.4.x through 2.4.0. This issue resides in the lib/flow.c component of ovs-vswitchd, the core daemon responsible for managing virtual switch operations in Open vSwitch deployments. The vulnerability manifests when processing MPLS (Multi-Protocol Label Switching) packets, which are commonly used in network virtualization and software-defined networking environments. The flaw enables remote attackers to execute arbitrary code on systems running vulnerable versions of Open vSwitch, potentially compromising the entire virtualized network infrastructure.
The technical exploitation of this vulnerability occurs through crafted MPLS packets that contain oversized string data within the flow processing logic. When ovs-vswitchd processes these malformed packets, the insufficient bounds checking in the flow.c module leads to a buffer overflow condition that can be leveraged to overwrite adjacent memory locations. This memory corruption typically occurs during the parsing of MPLS labels, where the system fails to properly validate the length of string data before copying it into fixed-size buffers. The vulnerability specifically targets the ovs-appctl command interface, which provides administrative control over the Open vSwitch daemon, making it possible for attackers to gain elevated privileges and execute malicious code with the same privileges as the ovs-vswitchd process.
The operational impact of CVE-2016-2074 extends beyond simple code execution, as it represents a significant threat to network infrastructure security in virtualized environments. Organizations utilizing Open vSwitch for software-defined networking, cloud computing platforms, or network virtualization deployments face potential compromise of their entire virtual network fabric. The vulnerability's remote exploitability means that attackers need not have direct network access to the switch itself, but can instead target the management interfaces or any network path that allows MPLS packet transmission. This makes the attack surface particularly broad in complex network environments where MPLS is commonly deployed for traffic engineering and quality of service implementations. The attack could result in complete system compromise, data exfiltration, or disruption of network services that depend on Open vSwitch for virtual network switching operations.
Security mitigations for this vulnerability require immediate patching of affected Open vSwitch installations to versions 2.3.3 or 2.4.1 and later, which contain the necessary bounds checking fixes for the flow.c module. Network administrators should also implement defensive measures such as MPLS packet filtering at network boundaries to prevent malformed packets from reaching vulnerable systems. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in network protocol processing. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for execution through command and scripting interpreter, and T1190 for exploitation of remote services. Organizations should also consider implementing network segmentation and monitoring to detect anomalous MPLS packet patterns that could indicate exploitation attempts, while maintaining updated vulnerability management processes to identify and remediate similar issues in other network infrastructure components.