CVE-2020-3207 in IOS XE
Summary
by MITRE
A vulnerability in the processing of boot options of specific Cisco IOS XE Software switches could allow an authenticated, local attacker with root shell access to the underlying operating system (OS) to conduct a command injection attack during device boot. This vulnerability is due to insufficient input validation checks while processing boot options. An attacker could exploit this vulnerability by modifying device boot options to execute attacker-provided code. A successful exploit may allow an attacker to bypass the Secure Boot process and execute malicious code on an affected device with root-level privileges.
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Analysis
by VulDB Data Team • 10/21/2020
The vulnerability identified as CVE-2020-3207 resides within Cisco IOS XE Software switches and represents a critical security flaw in the boot process validation mechanisms. This weakness specifically targets the handling of boot options during device initialization, creating an attack surface where authenticated local adversaries can manipulate system behavior. The vulnerability stems from inadequate input validation procedures that fail to properly sanitize or verify the integrity of boot parameters, allowing malicious modifications to persist through the system startup sequence. The flaw is particularly concerning because it operates at a fundamental level of system operation where the device loads its operating environment, making it a prime target for persistent compromise attempts.
The technical exploitation of this vulnerability requires an attacker to possess root shell access to the underlying operating system, which establishes a privileged foothold within the device's environment. Once achieved, the attacker can modify boot options to include malicious commands that will execute during the next device reboot cycle. This command injection capability bypasses the Secure Boot process, which is designed to ensure that only authorized and verified code executes during system initialization. The vulnerability's impact extends beyond simple code execution as it allows for complete system compromise with root-level privileges, potentially enabling attackers to establish persistent backdoors, exfiltrate sensitive data, or disrupt network operations. The attack vector leverages the trust placed in legitimate boot parameters, making detection more challenging as malicious activities occur during normal system operations.
From an operational perspective, this vulnerability poses significant risks to network infrastructure security, particularly in environments where Cisco switches serve as critical network components. The ability to bypass Secure Boot mechanisms means that attackers can potentially load malicious firmware or operating system components that maintain persistence across reboots, effectively creating a rootkit-like condition. The impact on network availability and security is substantial as compromised switches can become entry points for broader network infiltration, allowing attackers to monitor traffic, redirect connections, or disable security controls. Organizations relying on these switches for network segmentation, access control, or security enforcement may experience complete loss of control over their network infrastructure, with potential cascading effects throughout the entire network ecosystem.
Mitigation strategies for CVE-2020-3207 should focus on both immediate remediation and long-term security enhancements. Cisco has released patches and software updates to address this vulnerability, which organizations must deploy promptly to eliminate the risk of exploitation. Network administrators should implement strict access controls to limit root shell access and ensure that only authorized personnel can modify device configurations. The principle of least privilege should be enforced through proper user account management and session monitoring to prevent unauthorized access to privileged system interfaces. Additionally, organizations should consider implementing network segmentation and monitoring solutions that can detect anomalous boot behavior or unauthorized configuration changes. This vulnerability aligns with CWE-77 and CWE-78 categories related to command injection and input validation failures, and represents a technique that could be mapped to ATT&CK tactic TA0003 (Persistence) and technique T1059.001 (Command and Scripting Interpreter) in threat modeling frameworks. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network components and ensure comprehensive protection against similar attack vectors.