CVE-2020-3223 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 with administrative privileges to read arbitrary files on the underlying filesystem of the device. The vulnerability is due to insufficient file scope limiting. An attacker could exploit this vulnerability by creating a specific file reference on the filesystem and then accessing it through the web UI. An exploit could allow the attacker to read arbitrary files from the underlying operating system's filesystem.
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Analysis
by VulDB Data Team • 10/21/2020
The vulnerability identified as CVE-2020-3223 represents a critical security flaw within Cisco IOS XE Software's web-based user interface that enables authenticated remote attackers with administrative privileges to access arbitrary files on the underlying filesystem. This vulnerability stems from inadequate file scope limiting mechanisms that fail to properly restrict file access permissions within the web UI framework. The flaw exists specifically within the web interface component of Cisco IOS XE Software, which serves as the primary management interface for network devices running this operating system. Attackers exploiting this vulnerability can leverage the web UI to traverse the filesystem and retrieve sensitive data that should remain protected from unauthorized access. The vulnerability affects Cisco IOS XE Software versions prior to 16.12.04, making it particularly concerning for organizations running older software versions.
The technical implementation of this vulnerability involves insufficient input validation and access control measures within the web UI's file handling mechanisms. When an authenticated administrator accesses the web interface, the system fails to properly validate file paths and references, allowing attackers to craft specific file references that bypass normal file access restrictions. This weakness creates a path traversal condition where attackers can manipulate file access requests to read files outside of the intended scope. The vulnerability operates through the web UI's file browsing and management functions, where legitimate administrative operations are performed alongside potentially malicious file access attempts. According to CWE classification, this vulnerability maps to CWE-22 Path Traversal and CWE-23 Improper Limiting of a Pathname to a Restricted Directory, both of which are well-documented weaknesses in file access control systems.
The operational impact of CVE-2020-3223 extends beyond simple unauthorized file access, as it provides attackers with the ability to extract sensitive information from network devices. Attackers could potentially read configuration files, system logs, authentication credentials, and other confidential data that resides on the device's filesystem. This capability enables sophisticated attack scenarios where adversaries can gather intelligence for further exploitation or conduct data exfiltration operations. The vulnerability's remote exploitation capability means that attackers do not require physical access to the device, and the requirement for administrative privileges significantly reduces the barrier to exploitation. Organizations running affected Cisco IOS XE Software versions face potential compromise of their network infrastructure, as attackers can access critical system information that could be used to plan more extensive attacks against the network environment.
Mitigation strategies for CVE-2020-3223 primarily focus on upgrading affected Cisco IOS XE Software to versions that address the file scope limiting deficiencies. Cisco released patches and software updates in versions 16.12.04 and later that correct the insufficient file access controls within the web UI. Organizations should prioritize immediate deployment of these security updates to protect their network infrastructure from exploitation attempts. Network segmentation and access control measures should be implemented to limit administrative access to network devices, reducing the attack surface for potential exploitation. Additionally, monitoring for suspicious file access patterns and implementing network-based intrusion detection systems can help identify exploitation attempts. The vulnerability's classification under ATT&CK technique T1078 Valid Accounts indicates that attackers can leverage legitimate administrative credentials to exploit this weakness, making proper credential management and access control policies essential for defense. Organizations should also consider implementing web application firewalls and additional security controls to monitor and restrict access to the web UI components that handle file operations.