CVE-2020-3238 in IOS
Summary
by MITRE
A vulnerability in the Cisco Application Framework component of the Cisco IOx application environment could allow an authenticated, remote attacker to write or modify arbitrary files in the virtual instance that is running on the affected device. The vulnerability is due to insufficient input validation of user-supplied application packages. An attacker who can upload a malicious package within Cisco IOx could exploit the vulnerability to modify arbitrary files. The impacts of a successful exploit are limited to the scope of the virtual instance and do not affect the device that is hosting Cisco IOx.
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Analysis
by VulDB Data Team • 10/21/2020
The vulnerability identified as CVE-2020-3238 resides within the Cisco Application Framework component of the Cisco IOx application environment, representing a critical security flaw that enables authenticated remote attackers to manipulate file systems within virtual instances. This weakness specifically targets the insufficient input validation mechanisms implemented for user-supplied application packages, creating an avenue for malicious actors to upload compromised packages that can subsequently exploit the vulnerability. The affected Cisco IOx environment operates as a containerized application platform that hosts virtual instances on network devices, making this vulnerability particularly concerning for enterprise network infrastructure. The security implications extend beyond simple file modification capabilities, as the flaw allows for arbitrary file write operations that can potentially compromise the integrity of the entire virtualized application environment. This vulnerability operates at the intersection of software supply chain security and virtualization security, where trusted application deployment mechanisms become attack vectors for privilege escalation and persistent access. The Cisco IOx framework is designed to enable third-party applications to run on Cisco networking devices, creating a legitimate but potentially dangerous pathway for attackers who can authenticate to the system.
The technical exploitation of CVE-2020-3238 relies on the absence of proper validation checks within the application package handling process, specifically during the installation or update phases of IOx applications. When an authenticated user uploads a malicious application package, the vulnerable system fails to adequately sanitize or validate the contents of the package before deploying it within the virtual instance environment. This insufficient validation creates a condition where the attacker can include malicious file paths or overwrite existing system files within the virtual instance boundaries. The vulnerability demonstrates characteristics consistent with CWE-20, which describes improper input validation, and CWE-73, which addresses external control of file name or path. Attackers can leverage this flaw to modify system configuration files, inject malicious code into running applications, or establish persistence mechanisms within the virtual instance. The exploitation process requires authentication to the IOx management interface, which means that the attack vector is not purely remote but rather requires initial access through legitimate administrative credentials or compromised accounts. The vulnerability's impact is contained within the virtual instance boundaries, but this containment does not prevent significant operational disruption or data compromise within that scope.
The operational impact of CVE-2020-3238 extends beyond simple unauthorized file modification, as it enables attackers to potentially compromise the integrity of deployed applications and the data they process. Within the context of network infrastructure, this vulnerability can lead to service disruption, data exfiltration, or the establishment of persistent backdoors within virtualized applications that are meant to enhance network functionality. The affected environment typically includes network devices such as routers, switches, and security appliances that host IOx applications for tasks like traffic analysis, security monitoring, or application delivery. Attackers exploiting this vulnerability could modify application configurations, inject malicious code into legitimate applications, or manipulate data processing flows to redirect traffic or alter network behavior. The limited scope of impact to the virtual instance does not diminish the operational risk, as these instances often process sensitive network traffic or maintain critical network functions. The vulnerability creates a pathway for attackers to establish persistent access within network perimeters, potentially leading to extended reconnaissance activities and lateral movement within the network infrastructure. According to ATT&CK framework, this vulnerability maps to techniques involving privilege escalation and persistence mechanisms, specifically targeting the application deployment and execution phases of network security operations.
Mitigation strategies for CVE-2020-3238 should focus on strengthening input validation mechanisms within the Cisco IOx application framework and implementing robust access controls for IOx management interfaces. Organizations should ensure that all IOx applications undergo strict validation and verification processes before deployment, including automated scanning for malicious file patterns and content. Network administrators should enforce least privilege principles for IOx access, limiting the number of users who can upload or modify application packages within the IOx environment. Cisco has released patches addressing this vulnerability through security updates that improve input validation and enhance the security of application package handling within the IOx framework. Regular monitoring of IOx application deployments and suspicious file modification activities should be implemented as part of security operations. The mitigation approach should include network segmentation to limit the potential impact of successful exploitation and ensure that IOx applications operate with minimal necessary privileges within their virtual instances. Security teams should also implement comprehensive logging and audit capabilities for IOx management activities to detect unauthorized modifications or suspicious package uploads. Additional controls such as application whitelisting and mandatory access controls can provide additional layers of protection against exploitation attempts. The vulnerability highlights the importance of securing application deployment mechanisms and demonstrates the need for comprehensive security testing of virtualization and containerization platforms within enterprise network environments.