CVE-2015-0658 in NX-OS
Summary
by MITRE
The DHCP implementation in the PowerOn Auto Provisioning (POAP) feature in Cisco NX-OS does not properly restrict the initialization process, which allows remote attackers to execute arbitrary commands as root by sending crafted response packets on the local network, aka Bug ID CSCur14589.
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Analysis
by VulDB Data Team • 04/16/2022
The vulnerability described in CVE-2015-0658 resides within the PowerOn Auto Provisioning feature of Cisco NX-OS operating systems, specifically affecting the Dynamic Host Configuration Protocol implementation. This flaw represents a critical security weakness that enables remote attackers to gain unauthorized root-level access to network devices through carefully crafted network packets. The POAP feature is designed to automatically provision network equipment during initial boot processes, making it a crucial component for network deployment and management. However, the improper restriction of the initialization process creates a significant attack surface that adversaries can exploit without requiring physical access or prior authentication credentials.
The technical implementation flaw stems from insufficient validation and sanitization of DHCP response packets received during the auto provisioning phase. When network devices boot and initiate the POAP process, they expect to receive specific DHCP responses containing configuration information. The vulnerability occurs because the system fails to properly validate the source and content of these responses, allowing malicious actors to inject crafted packets that manipulate the provisioning workflow. This improper input handling creates a command injection vulnerability that executes with root privileges due to the privileged nature of the POAP initialization process. The attack vector requires only network access to the local network segment where the vulnerable device resides, making it particularly dangerous as it can be exploited from adjacent network locations.
The operational impact of this vulnerability is severe and far-reaching for network administrators and security teams. Successful exploitation results in complete compromise of affected network devices, enabling attackers to execute arbitrary commands with the highest possible privileges. This level of access allows for complete network takeover, including the ability to modify device configurations, install malicious software, redirect network traffic, and establish persistent backdoors. The vulnerability affects Cisco Nexus series switches running NX-OS versions prior to the patched releases, with the specific bug ID CSCur14589 documenting the issue within Cisco's internal tracking systems. Organizations with large network infrastructures face significant risk as a single compromised device can serve as a foothold for broader network infiltration, potentially affecting multiple network segments and services.
Mitigation strategies for CVE-2015-0658 require immediate action from network administrators to address the identified vulnerability. The primary recommendation involves applying the relevant Cisco security patches and updates that fix the DHCP implementation flaws in the POAP feature. Organizations should also implement network segmentation and access controls to limit the exposure of vulnerable devices to untrusted network segments. Network administrators can deploy DHCP snooping and other network monitoring solutions to detect and prevent malicious DHCP responses from reaching affected devices. Additionally, disabling the POAP feature on devices where it is not strictly required provides an effective workaround until proper patches are applied. This vulnerability aligns with CWE-77 and CWE-20 categories, representing command injection and input validation flaws respectively, and maps to ATT&CK techniques involving privilege escalation and remote code execution. Security teams should conduct comprehensive vulnerability assessments to identify all affected devices and implement layered defense strategies to prevent exploitation attempts.