CVE-2020-3229 in IOS XE
Summary
by MITRE
A vulnerability in Role Based Access Control (RBAC) functionality of Cisco IOS XE Web Management Software could allow a Read-Only authenticated, remote attacker to execute commands or configuration changes as an Admin user. The vulnerability is due to incorrect handling of RBAC for the administration GUI. An attacker could exploit this vulnerability by sending a modified HTTP request to the affected device. An exploit could allow the attacker as a Read-Only user to execute CLI commands or configuration changes as if they were an Admin user.
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Analysis
by VulDB Data Team • 10/21/2020
This vulnerability resides within the Role Based Access Control implementation of Cisco IOS XE Web Management Software, representing a critical authorization flaw that undermines the fundamental security model of the system. The issue stems from improper handling of access controls within the administration graphical user interface, creating a privilege escalation pathway that allows attackers to bypass intended security boundaries. The vulnerability affects the core RBAC functionality that should enforce strict separation between user roles, specifically enabling a Read-Only authenticated user to gain administrative privileges through manipulation of the web interface.
The technical exploitation occurs through the manipulation of HTTP requests sent to the affected device, leveraging a flaw in how the software processes authentication tokens and session management within the GUI framework. This misconfiguration allows an attacker to craft specific requests that appear to originate from an administrative session while actually being executed by a user with read-only privileges. The vulnerability essentially creates a backdoor mechanism within the legitimate web interface that bypasses normal authorization checks, enabling command execution and configuration modifications that should only be available to administrators.
From an operational impact perspective, this vulnerability presents a severe threat to network security infrastructure as it allows attackers to escalate privileges without requiring additional authentication mechanisms or physical access to the device. The remote nature of the exploit means that attackers can operate from outside the network perimeter, making detection and prevention more challenging. Organizations utilizing Cisco IOS XE devices face significant risk of unauthorized access to critical network configurations, potentially leading to complete network compromise, data exfiltration, or service disruption. The vulnerability essentially transforms any authenticated read-only user into a potential administrator, undermining the principle of least privilege that forms the foundation of secure network design.
The flaw aligns with CWE-285, which addresses improper authorization issues in software systems, and demonstrates characteristics consistent with ATT&CK technique T1078.004 for valid accounts and T1548.002 for abuse of cloud platforms, though adapted to network device contexts. Mitigation strategies should include immediate patch deployment from Cisco, implementation of network segmentation to limit access to administrative interfaces, and enhanced monitoring of HTTP traffic for suspicious request patterns. Organizations should also consider disabling unnecessary web management interfaces, implementing strict access controls for administrative functions, and conducting regular security audits to identify similar privilege escalation vulnerabilities. The vulnerability highlights the importance of thorough security testing of authentication mechanisms and the need for comprehensive access control validation in network infrastructure software.
Additional defensive measures include deploying web application firewalls to monitor and filter HTTP requests, implementing multi-factor authentication for administrative access, and establishing strict network access controls that limit which systems can reach administrative interfaces. Security teams should also monitor for unusual administrative activity patterns and implement logging controls that can detect privilege escalation attempts. The vulnerability serves as a reminder that even seemingly minor access control flaws in network infrastructure can have catastrophic consequences for overall network security posture.