CVE-2016-6457 in NX-OS
Summary
by MITRE
A vulnerability in the Cisco Nexus 9000 Series Platform Leaf Switches for Application Centric Infrastructure (ACI) could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on the affected device. This vulnerability affects Cisco Nexus 9000 Series Leaf Switches (TOR) - ACI Mode and Cisco Application Policy Infrastructure Controller (APIC). More Information: CSCuy93241. Known Affected Releases: 11.2(2x) 11.2(3x) 11.3(1x) 11.3(2x) 12.0(1x). Known Fixed Releases: 11.2(2i) 11.2(2j) 11.2(3f) 11.2(3g) 11.2(3h) 11.2(3l) 11.3(0.236) 11.3(1j) 11.3(2i) 11.3(2j) 12.0(1r).
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Analysis
by VulDB Data Team • 10/04/2022
The vulnerability identified as CVE-2016-6457 represents a significant denial of service weakness in Cisco's Nexus 9000 Series Leaf Switches operating in Application Centric Infrastructure mode. This flaw specifically targets the ACI environment where these switches function as top-of-rack devices, creating a critical operational risk for network infrastructure. The vulnerability stems from insufficient input validation mechanisms within the switch's processing pipeline, particularly when handling specific network protocols or management messages. An attacker positioned within the same network segment can exploit this weakness without requiring authentication credentials, making the attack surface particularly concerning for production environments where physical network access might be compromised.
The technical exploitation of this vulnerability occurs through crafted network packets or management communications that trigger a buffer overflow or memory corruption condition within the switch's processing modules. This condition leads to the switch's immediate or gradual failure to process legitimate network traffic, effectively creating a denial of service scenario that can persist until manual intervention occurs. The vulnerability affects multiple software versions across the 11.2 and 11.3 release lines, indicating it was present in several iterations of the software stack and likely introduced during a specific code modification or protocol handling implementation. The affected devices include both the leaf switches in ACI mode and the Application Policy Infrastructure Controller, creating a cascading impact that could potentially disrupt entire application-centric network domains.
The operational impact of this vulnerability extends beyond simple network disruption to potentially compromise business continuity and application availability within data center environments. Organizations relying on ACI for network virtualization and policy enforcement face significant risk when these switches become unavailable, as they may lose connectivity between application workloads and their underlying network infrastructure. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of how insufficient bounds checking can create exploitable conditions in network infrastructure devices. The attack vector specifically corresponds to ATT&CK technique T1499.001, which involves network disruption through denial of service attacks, making this vulnerability particularly relevant to threat actors seeking to disrupt network operations.
Mitigation strategies for CVE-2016-6457 require immediate deployment of the vendor-supplied patches and firmware updates that address the underlying buffer overflow conditions. Network administrators should prioritize updating all affected switches in the 11.2(2x), 11.2(3x), 11.3(1x), 11.3(2x), and 12.0(1x) release versions to the corresponding fixed releases. Additional protective measures include implementing network segmentation to limit physical access to these devices, deploying intrusion detection systems to monitor for anomalous traffic patterns that might indicate exploitation attempts, and establishing robust network monitoring protocols to quickly identify and respond to DoS conditions. The vulnerability demonstrates the critical importance of maintaining current security patches for network infrastructure devices, as even minor software versions can contain exploitable conditions that significantly impact operational availability. Organizations should also conduct regular vulnerability assessments and penetration testing to identify similar conditions that might exist in other network equipment within their infrastructure.