CVE-2021-1584 in Nexus 9000
Summary
by MITRE • 08/26/2021
A vulnerability in Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an authenticated, local attacker to elevate privileges on an affected device. This vulnerability is due to insufficient restrictions during the execution of a specific CLI command. An attacker with administrative privileges could exploit this vulnerability by performing a command injection attack on the vulnerable command. A successful exploit could allow the attacker to access the underlying operating system as root.
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Analysis
by VulDB Data Team • 08/29/2021
This vulnerability exists within Cisco Nexus 9000 Series Fabric Switches operating in Application Centric Infrastructure mode and represents a critical privilege escalation flaw that could compromise the entire network infrastructure. The vulnerability stems from inadequate input validation and sanitization mechanisms within specific command-line interface commands, creating a pathway for authenticated attackers to execute malicious code with elevated privileges. The flaw specifically affects the way the system processes certain CLI commands, allowing for command injection attacks that bypass normal security restrictions and authentication checks.
The technical exploitation of this vulnerability requires an attacker to already possess administrative credentials, making it a local privilege escalation issue rather than a remote code execution vulnerability. However, the impact remains severe as the attacker can leverage their existing administrative access to inject malicious commands that ultimately elevate their privileges to the root level of the underlying operating system. This command injection occurs due to insufficient restrictions during command execution, where user-supplied input is not properly validated or escaped before being processed by the system. The vulnerability essentially allows an attacker to bypass the normal access control mechanisms that should prevent administrative users from executing arbitrary system-level commands.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over the affected switch infrastructure. Once elevated to root privileges, an attacker could modify network configurations, access sensitive data, redirect traffic, or even disable network services entirely. This represents a significant threat to network security and stability, particularly in enterprise environments where these switches form the core of ACI deployments. The vulnerability affects the integrity and availability of the network infrastructure, potentially allowing attackers to cause widespread disruption or data breaches across the connected network segments.
Mitigation strategies for this vulnerability should include immediate application of Cisco's security patches and updates to address the command injection flaw. Network administrators should also implement strict access controls and monitor administrative activities for suspicious command sequences. The principle of least privilege should be enforced to minimize the potential impact of compromised administrative accounts. Organizations should conduct thorough vulnerability assessments to identify all affected devices and implement network segmentation to limit the attack surface. Additionally, regular security monitoring and logging of CLI activities can help detect potential exploitation attempts. This vulnerability aligns with CWE-77 and CWE-20 categories related to command injection and input validation flaws, and it maps to ATT&CK techniques involving privilege escalation and command execution within compromised systems.