CVE-2019-1862 in IOS XE
Summary
by MITRE
A vulnerability in the web-based user interface (Web UI) of Cisco IOS XE Software could allow an authenticated, remote attacker to execute commands on the underlying Linux shell of an affected device with root privileges. The vulnerability occurs because the affected software improperly sanitizes user-supplied input. An attacker who has valid administrator access to an affected device could exploit this vulnerability by supplying a crafted input parameter on a form in the Web UI and then submitting that form. A successful exploit could allow the attacker to run arbitrary commands on the device with root privileges, which may lead to complete system compromise.
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Analysis
by VulDB Data Team • 09/17/2023
This vulnerability resides in the web-based user interface of Cisco IOS XE Software, representing a critical command injection flaw that enables authenticated remote attackers to escalate privileges and execute arbitrary code with root-level access. The vulnerability stems from insufficient input sanitization mechanisms within the Web UI component, specifically when processing user-supplied parameters submitted through web forms. Attackers with valid administrator credentials can exploit this weakness by crafting malicious input parameters that bypass security controls and directly interface with the underlying Linux shell of the affected device.
The technical exploitation occurs through a classic command injection vector where the vulnerable software fails to properly validate or sanitize user input before processing it within the system's command execution pipeline. This improper sanitization creates a pathway for attackers to inject malicious commands that are then executed with the highest privileges available on the system. The vulnerability specifically affects the Web UI's form handling mechanisms, where submitted parameters containing special characters or command sequences can be interpreted by the underlying operating system rather than being properly escaped or filtered. This flaw directly maps to CWE-77 which describes command injection vulnerabilities, and represents a significant bypass of the principle of least privilege that should normally prevent web interface access from translating to system-level command execution.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as successful exploitation provides attackers with complete control over the affected device. With root privileges, attackers can modify system configurations, install malicious software, access sensitive data, and potentially use the compromised device as a pivot point for further attacks within the network infrastructure. The vulnerability's remote nature and authentication requirement mean that attackers need only valid administrative credentials to achieve system compromise, making it particularly dangerous in environments where administrative access is granted to multiple users. This represents a critical failure in the principle of defense in depth, as the web interface should not provide direct access to underlying system commands regardless of user authentication status.
Organizations should implement immediate mitigations including restricting administrative access to devices, implementing network segmentation to limit exposure, and applying Cisco's official security patches as soon as they become available. The vulnerability demonstrates the importance of input validation and the principle of least privilege in web application security, as the system should not allow web interface parameters to directly translate into system-level command execution. Security monitoring should be enhanced to detect unusual command execution patterns and unauthorized administrative access attempts. Additionally, organizations should consider implementing web application firewalls and input validation controls to prevent similar vulnerabilities from being exploited through other attack vectors, aligning with ATT&CK technique T1059.004 for command and script injection. The vulnerability also highlights the need for regular security assessments of web interfaces and proper security testing during software development lifecycle to prevent such critical flaws from reaching production environments.