CVE-2018-0307 in NX-OS
Summary
by MITRE
A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated, local attacker to perform a command-injection attack on an affected device. The vulnerability is due to insufficient input validation of command arguments. An attacker could exploit this vulnerability by injecting malicious command arguments into a vulnerable CLI command. A successful exploit could allow the attacker, authenticated as a privileged user, to execute arbitrary commands with root privileges. Note: On products that support multiple virtual device contexts (VDC), this vulnerability could allow an attacker to access files from any VDC. This vulnerability affects Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 3600 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules. Cisco Bug IDs: CSCve51704, CSCve91749, CSCve91768.
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Analysis
by VulDB Data Team • 03/28/2023
This vulnerability resides within the command-line interface of Cisco NX-OS software, representing a critical security flaw that enables authenticated local attackers to execute arbitrary commands with root privileges. The core issue stems from inadequate input validation mechanisms within the CLI command processing framework, specifically failing to properly sanitize command arguments before execution. The vulnerability manifests when legitimate CLI commands accept user-supplied parameters that are not adequately validated or escaped, creating an injection vector that malicious actors can exploit. This flaw affects a broad spectrum of Cisco networking equipment including various Nexus series switches and fabric extenders, spanning multiple platform families and product lines.
The technical exploitation of CVE-2018-0307 follows a command injection pattern that aligns with CWE-77 and CWE-94 categories, where insufficient validation of input data allows attackers to inject malicious commands into the system's execution pipeline. An authenticated attacker with privileged access can manipulate command arguments to inject arbitrary shell commands, bypassing normal access controls and executing code with the highest system privileges. The vulnerability's impact extends beyond individual device boundaries when multiple virtual device contexts (VDC) are present, as it allows cross-context file access and manipulation. This cross-contamination aspect significantly amplifies the attack surface and potential damage, as an attacker could access sensitive data or configuration files from other VDC instances without proper authorization.
The operational implications of this vulnerability are severe for enterprise network infrastructure, as it provides a path for attackers to gain complete system control over affected devices. Once exploited, attackers can modify network configurations, access sensitive data, install backdoors, or disable security features, potentially compromising the entire network segment. The vulnerability's persistence across multiple Nexus platform families and product generations indicates a systemic design flaw in the CLI processing architecture rather than a product-specific issue. Network administrators face the challenge of securing devices across various hardware platforms while maintaining operational continuity, as this vulnerability can be exploited by attackers who have already gained legitimate access to the device.
Mitigation strategies should focus on immediate software updates and patches provided by Cisco to address the input validation deficiencies in the affected CLI components. Organizations must also implement strict access controls and monitoring of CLI activities to detect potential exploitation attempts. Network segmentation and privilege separation can help limit the impact of successful exploitation, while regular security audits and vulnerability assessments should be conducted to identify similar input validation weaknesses. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically leveraging command injection methods to gain root-level access. Organizations should also consider implementing network access controls and monitoring solutions that can detect anomalous CLI command patterns and unauthorized access attempts. The vulnerability underscores the importance of robust input validation practices in network device software, as highlighted by industry standards and best practices for secure coding.