CVE-2020-3452 in ASA
Summary
by MITRE
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct directory traversal attacks and read sensitive files on a targeted system. The vulnerability is due to a lack of proper input validation of URLs in HTTP requests processed by an affected device. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences to an affected device. A successful exploit could allow the attacker to view arbitrary files within the web services file system on the targeted device. The web services file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability cannot be used to obtain access to ASA or FTD system files or underlying operating system (OS) files.
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Analysis
by VulDB Data Team • 02/24/2025
The vulnerability identified as CVE-2020-3452 represents a critical directory traversal flaw affecting Cisco Adaptive Security Appliance (ASA) and Cisco Firepower Threat Defense (FTD) software implementations. This weakness exists within the web services interface component of these security appliances, creating a pathway for unauthenticated remote attackers to access sensitive system files without proper authorization. The vulnerability specifically targets the HTTP request processing mechanism where insufficient input validation allows malicious actors to manipulate URL parameters through crafted directory traversal sequences. Security professionals should recognize this issue as a prime example of improper input validation that violates fundamental security principles and creates persistent attack vectors.
The technical exploitation of CVE-2020-3452 relies on the absence of proper sanitization within the web services component of Cisco's security appliances. When an attacker crafts malicious HTTP requests containing sequences such as "../" or similar directory traversal patterns, the vulnerable system fails to properly validate these inputs before processing them. This failure allows the attacker to navigate through the file system hierarchy and access files that should remain restricted to authorized users. The vulnerability operates at the application layer and specifically affects the web services interface, which becomes accessible when either WebVPN or AnyConnect features are enabled on the affected device. According to CWE classification, this represents a CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability, which falls under the broader category of input validation failures that consistently plague web applications and network security devices.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the ability to extract sensitive configuration data, user credentials, and other confidential information stored within the web services file system. While the vulnerability cannot be used to access underlying operating system files or gain direct system access, the exposure of web services files still presents significant risks to network security posture. Attackers can potentially retrieve administrative configuration files, certificate stores, and other sensitive data that could aid in further exploitation attempts or provide insights into network architecture and security controls. The remote nature of this attack vector means that adversaries can exploit the vulnerability from outside the network perimeter without requiring any prior authentication credentials, making it particularly dangerous for organizations that maintain exposed web services interfaces.
Organizations affected by CVE-2020-3452 should implement immediate mitigations including applying Cisco's security patches and updates, disabling web services interfaces when not required, and implementing network segmentation controls to limit access to affected devices. The ATT&CK framework categorizes this vulnerability under T1083: File and Directory Discovery, as attackers can use the vulnerability to enumerate and access sensitive files within the targeted system. Network administrators should also consider implementing web application firewalls and intrusion detection systems to monitor for suspicious HTTP request patterns that may indicate exploitation attempts. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all instances of affected Cisco ASA and FTD devices within their network infrastructure and ensure proper configuration management to prevent unauthorized access to web services interfaces that could be exploited through this directory traversal vulnerability.