CVE-2020-3452: Cisco ASA and FTD Read-Only Path Traversal Vulnerability

Vulnerability summary

CVE-2020-3452 is a high (CVSS 7.5) Improper Input Validation vulnerability in Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 99.99% chance of exploitation in the next 30 days, higher than 99.9% of scored vulnerabilities. 6 public exploits are recorded.

Timeline

1. 22-07-2020
   PublishedVulnerability first disclosed.
2. 03-11-2021
   Added to CISA KEVCisco ASA and FTD Read-Only Path Traversal Vulnerability
3. 03-05-2022
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

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.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.