CVE-2016-1453 in NX-OS
Summary
by MITRE
Buffer overflow in the Overlay Transport Virtualization (OTV) GRE feature in Cisco NX-OS 5.0 through 7.3 on Nexus 7000 and 7700 devices allows remote attackers to execute arbitrary code via long parameters in a packet header, aka Bug ID CSCuy95701.
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Analysis
by VulDB Data Team • 05/04/2019
The vulnerability described in CVE-2016-1453 represents a critical buffer overflow condition within Cisco NX-OS software versions 5.0 through 7.3 that affects Nexus 7000 and 7700 series switches. This flaw specifically resides in the Overlay Transport Virtualization GRE (Generic Routing Encapsulation) feature implementation, which is fundamental to Cisco's data center networking solutions. The issue manifests when the system processes packets containing excessively long parameters in their header fields, creating a scenario where attacker-controlled input can overwrite adjacent memory locations beyond the intended buffer boundaries.
The technical nature of this vulnerability stems from inadequate input validation within the OTV GRE processing module. When network packets arrive containing malformed or oversized parameter fields within the GRE header structure, the system fails to properly bounds-check the incoming data before copying it into fixed-size memory buffers. This classic buffer overflow condition allows an attacker to craft malicious packets that, when processed by the affected switches, can overwrite critical memory locations including return addresses, function pointers, or other control data structures. The vulnerability operates at the network protocol level, making it particularly dangerous as it can be exploited through standard network traffic without requiring physical access or authentication credentials.
The operational impact of this vulnerability is severe and far-reaching within enterprise and data center environments. Remote attackers capable of sending specially crafted packets to vulnerable Cisco Nexus switches can potentially execute arbitrary code with the privileges of the affected system processes, typically resulting in complete system compromise. This allows adversaries to gain unauthorized access to the network infrastructure, potentially enabling them to redirect traffic, establish backdoors, or use the compromised devices as launch points for further attacks against internal network resources. The vulnerability affects critical network infrastructure components that often serve as core forwarding elements in data center environments, making successful exploitation particularly damaging for organizations relying on these devices for network connectivity and security.
Cisco has addressed this vulnerability through software updates and patches released as part of their regular security advisory program, specifically targeting the affected NX-OS versions. Organizations should immediately implement these patches across all affected Nexus 7000 and 7700 series devices to mitigate the risk. Network segmentation and access control measures can provide additional defense-in-depth, such as restricting network access to only trusted sources and implementing monitoring for unusual packet patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and represents a typical entry point for privilege escalation attacks as outlined in the MITRE ATT&CK framework under techniques related to remote code execution and system compromise. Organizations should also consider implementing network intrusion detection systems that can identify and alert on malformed GRE packets that might be part of exploitation attempts against this specific vulnerability.