Vulnerability record · CVE-2020-3452 · published 22 July 2020
CVE-2020-3452: Cisco ASA and FTD web services path traversal file read
Cisco · Adaptive Security Appliance Software
Cisco ASA and FTD web services fail to validate URL input, allowing directory traversal sequences in HTTP requests to read files inside the web services file system. The flaw is remotely reachable without authentication and only affects devices with WebVPN or AnyConnect enabled, exposing configuration and session-related files rather than ASA/FTD system or OS files.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Automated analysis
high priorityUnauthenticated remote file disclosure with public exploits, KEV listing and near-maximum EPSS, though impact is limited to the web services file system.
What it is
Cisco ASA and FTD web services fail to validate URL input, allowing directory traversal sequences in HTTP requests to read files inside the web services file system. The flaw is remotely reachable without authentication and only affects devices with WebVPN or AnyConnect enabled, exposing configuration and session-related files rather than ASA/FTD system or OS files.
Impact
An unauthenticated attacker can read arbitrary files within the web services file system, which may include credentials, session data or configuration material useful for follow-on access. It does not grant access to ASA/FTD system or underlying OS files.
Attack surface
Reached over the network through the web services interface (HTTP) when WebVPN or AnyConnect is configured; no authentication or user interaction is required per the CVSS vector (AV:N/AC:L/PR:N/UI:N).
Exploitation
Listed in CISA KEV since 2021-11-03 with a required action to apply vendor updates, and EPSS 30-day probability is 0.99992 (99.987th percentile); multiple public references are tagged Exploit.
What to do
- Apply the Cisco vendor updates for ASA and FTD per the security advisory.
- If WebVPN or AnyConnect is not required, disable those features to remove the exposed web services file system.
- Restrict management and web services access to trusted networks and block traversal patterns at the perimeter.
- Monitor for and rotate any credentials or secrets that may have been stored in web services files.
- Verify remediation against the KEV due date and track completion.
Detection
- Inspect HTTP requests to ASA/FTD web services for directory traversal sequences such as ../ or encoded variants.
- Alert on anomalous access to web services file paths from untrusted source IPs.
- Review web services access logs for repeated or automated file retrieval attempts.
- Correlate outbound scanning or exploitation attempts against ASA/FTD management interfaces with known exploit tooling.
This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.
Exploitation in the wild
CISA added CVE-2020-3452 to the Known Exploited Vulnerabilities catalog on 3 November 2021 as "Cisco ASA and FTD Read-Only Path Traversal Vulnerability". Required action: Apply updates per vendor instructions. Federal deadline 3 May 2022.
Affected products
2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
Track CVE-2020-3452 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2020-3452), CISA KEV, FIRST EPSS (scores of 2026-09-16). This page is refreshed as NVD updates the record.
