CyberBrief
Subscribe
9.1Critical

Cisco Secure Firewall Threat Defense

CVE-2020-3187

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 obtain read and delete access to sensitive files on a targeted system. The vulnerability is due to a lack of proper input validation of the HTTP URL. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences. An exploit could allow the attacker to view or delete arbitrary files on the targeted system. When the device is reloaded after exploitation of this vulnerability, any files that were deleted are restored. The attacker can only view and delete files within the web services file system. This file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability can not be used to obtain access to ASA or FTD system files or underlying operating system (OS) files. Reloading the affected device will restore all files within the web services file system.

What this means for your business

  • It affects Cisco Secure Firewall Threat Defense. It matters if your company, or a supplier that handles your data, runs it.
  • Code showing how to exploit it has been published, but real attacks have not been confirmed.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 97% chance of attack attempts being seen in the next 30 days, ranking above 99% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run Cisco Secure Firewall Threat Defense, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposedBook a call

Scoring

CVSS
9.1 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness
CWE-22
Assigned by
psirt@cisco.com

Dates

Published
2020-05-06
Last modified
2026-08-11
Sources
NVD

Affected products

  • Cisco Secure Firewall Threat Defense6.2.3 - 6.2.3.16, 6.3.0 - 6.3.0.6, 6.4.0 - 6.4.0.8, 6.5.0 - 6.5.0.4
  • Cisco Asa 5505 Firmware9.6\(4\)
  • Cisco Asa 5505all versions
  • Cisco Asa 5510 Firmware9.6\(4\)
  • Cisco Asa 5510all versions
  • Cisco Asa 5512-X Firmware9.6\(4\)
  • Cisco Asa 5512-Xall versions
  • Cisco Asa 5515-X Firmware9.6\(4\)
  • Cisco Asa 5515-Xall versions
  • Cisco Asa 5520 Firmware9.6\(4\)
  • Cisco Asa 5520all versions
  • Cisco Asa 5525-X Firmware9.6\(4\)

As listed in the NVD configuration data. Not a statement about your estate.

References