CVE-2020-3365 in Enterprise NFV Infrastructure Software
Summary
by MITRE
A vulnerability in the directory permissions of Cisco Enterprise NFV Infrastructure Software (NFVIS) could allow an authenticated, remote attacker to perform a directory traversal attack on a limited set of restricted directories. The vulnerability is due to a flaw in the logic that governs directory permissions. An attacker could exploit this vulnerability by using capabilities that are not controlled by the role-based access control (RBAC) mechanisms of the software. A successful exploit could allow the attacker to overwrite files on an affected device.
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Analysis
by VulDB Data Team • 11/12/2020
The vulnerability identified as CVE-2020-3365 affects Cisco Enterprise NFV Infrastructure Software (NFVIS) and represents a critical directory traversal flaw that undermines the software's permission controls. This issue stems from inadequate validation logic within the directory permission system, creating a pathway for authenticated remote attackers to exploit the system. The vulnerability specifically targets restricted directories within the NFVIS environment, where standard role-based access control mechanisms fail to properly govern access capabilities. The flaw allows attackers to bypass expected security boundaries through unauthorized file operations that should be restricted by the RBAC framework. This represents a fundamental breakdown in the software's security architecture where the permission model's logic is insufficient to prevent malicious traversal attempts.
The technical implementation of this vulnerability exploits the gap between the intended access controls and the actual permission enforcement mechanisms. Attackers can leverage the flawed directory permission logic to navigate beyond the intended scope of restricted directories, potentially accessing or modifying files that should remain protected. The vulnerability specifically affects the software's handling of file operations within limited restricted directories, where the RBAC mechanisms are supposed to enforce access restrictions. The exploitation process involves using capabilities that are not properly controlled by the role-based access control framework, effectively creating a backdoor for unauthorized file manipulation. This flaw demonstrates a weakness in the software's input validation and path resolution logic, allowing attackers to construct malicious paths that circumvent normal access controls.
The operational impact of CVE-2020-3365 extends beyond simple unauthorized access to potentially enabling complete system compromise through file overwrite operations. An attacker who successfully exploits this vulnerability can overwrite critical system files, potentially leading to service disruption, data corruption, or even complete system takeover. The restricted nature of the affected directories means that attackers cannot access all system files, but the ability to modify files within these limited scopes still provides significant leverage for malicious activities. The vulnerability affects the integrity of the NFVIS platform, as it undermines the fundamental security assumptions that users rely upon when configuring access controls. Organizations using Cisco NFVIS software face potential risks including unauthorized configuration changes, data integrity violations, and service availability impacts. This vulnerability directly impacts the software's ability to maintain secure file operations and can result in cascading security failures if attackers can escalate their privileges through the compromised file system access.
Mitigation strategies for CVE-2020-3365 should focus on immediate software updates and enhanced monitoring of file system operations. Cisco has released patches addressing this vulnerability, and organizations should prioritize applying these updates to all affected NFVIS deployments. Network segmentation and monitoring of file system access patterns can help detect potential exploitation attempts before they succeed. Implementing additional access controls beyond the standard RBAC mechanisms can provide defense-in-depth protection against similar vulnerabilities. Organizations should also conduct comprehensive security assessments of their NFVIS environments to identify any other potential permission-related flaws. The vulnerability highlights the importance of proper input validation and path resolution in security-critical applications, aligning with CWE-22 directory traversal weakness classifications. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation and defense evasion techniques, as attackers can use it to modify system files and potentially hide their activities. Regular security audits of directory permission logic and access control implementations should become standard practice to prevent similar issues in other software components.