CVE-2017-3851 in IOx
Summary
by MITRE
A Directory Traversal vulnerability in the web framework code of the Cisco application-hosting framework (CAF) component of the Cisco IOx application environment could allow an unauthenticated, remote attacker to read any file from the CAF in the virtual instance running on the affected device. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by submitting crafted requests to the CAF web interface. The impacts of a successful exploit are limited to the scope of the virtual instance and do not impact the router that is hosting Cisco IOx. Cisco IOx Releases 1.0.0.0 and 1.1.0.0 are vulnerable. Cisco Bug IDs: CSCuy52302.
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Analysis
by VulDB Data Team • 11/14/2022
The vulnerability identified as CVE-2017-3851 represents a critical directory traversal flaw within the Cisco Application Hosting Framework (CAF) component of the Cisco IOx application environment. This security weakness exists in the web framework code implementation and affects specific releases of the IOx platform including versions 1.0.0.0 and 1.1.0.0. The vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing requests through the CAF web interface. Attackers can exploit this flaw by crafting malicious HTTP requests that manipulate file path parameters to access unauthorized files within the virtual instance environment. The vulnerability operates at the application layer and specifically targets the web services exposed by the CAF component, making it particularly dangerous as it allows remote code execution capabilities without requiring authentication credentials.
The technical implementation of this directory traversal vulnerability demonstrates a classic input validation failure that aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory. The CAF web framework fails to adequately validate and sanitize file path inputs, allowing attackers to manipulate request parameters to traverse directory structures and access files that should remain restricted. When an attacker submits crafted requests containing sequences like "../" or similar path manipulation techniques, the vulnerable code processes these inputs without proper sanitization, resulting in unauthorized file access. This flaw specifically impacts the virtual instance hosting environment where the CAF component operates, creating a potential attack surface that could be leveraged to extract sensitive configuration files, application data, or other confidential information stored within the virtualized application environment. The vulnerability's design allows for arbitrary file reading within the scope of the virtual instance, though it is constrained to not affect the underlying router hosting the IOx service.
The operational impact of CVE-2017-3851 extends beyond simple information disclosure, as it creates a persistent threat vector that could be exploited for reconnaissance and further attack development. An attacker who successfully exploits this vulnerability can potentially access application configuration files, database contents, or other sensitive data stored within the virtual instance environment. The limited scope of the impact, while providing some containment, does not eliminate the threat as the compromised virtual instance may contain valuable data or serve as a foothold for additional attacks within the network. The vulnerability's remote nature means that attackers can exploit it from outside the network perimeter without requiring any prior authentication, making it particularly dangerous for organizations that deploy Cisco IOx services in environments with limited network segmentation. This weakness could enable attackers to gather intelligence about the target environment, potentially leading to more sophisticated attacks targeting the broader network infrastructure or other connected systems.
Organizations affected by this vulnerability should implement immediate mitigations including applying the relevant Cisco security patches and updates that address the directory traversal flaw in the CAF component. Network segmentation and access control measures should be enhanced to limit exposure of the affected Cisco IOx services to untrusted networks. The implementation of web application firewalls and input validation controls can provide additional protection layers against similar attacks targeting the CAF web interface. Regular security assessments and vulnerability scanning should be conducted to identify any potential exploitation attempts or related vulnerabilities within the IOx environment. Monitoring network traffic for suspicious request patterns containing directory traversal sequences can help detect exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving directory traversal and privilege escalation, specifically targeting the application layer and potentially enabling lateral movement within the compromised virtual instance environment. Organizations should also consider implementing principle of least privilege access controls for the CAF web interface and ensure that any sensitive data stored within virtual instances is properly protected through encryption and access controls. The vulnerability highlights the importance of secure coding practices and input validation in web application frameworks, particularly when dealing with file system operations and user-supplied data processing.