8.1High

Cisco Secure Firewall Management Center

CVE-2020-3549

A vulnerability in the sftunnel functionality of Cisco Firepower Management Center (FMC) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to obtain the device registration hash. The vulnerability is due to insufficient sftunnel negotiation protection during initial device registration. An attacker in a man-in-the-middle position could exploit this vulnerability by intercepting a specific flow of the sftunnel communication between an FMC device and an FTD device. A successful exploit could allow the attacker to decrypt and modify the sftunnel communication between FMC and FTD devices, allowing the attacker to modify configuration data sent from an FMC device to an FTD device or alert data sent from an FTD device to an FMC device.

What this means for your business

  • It affects Cisco Secure Firewall Management Center. It matters if your company, or a supplier that handles your data, runs it.
  • 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 0.9% chance of attack attempts being seen in the next 30 days, ranking above 59% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run Cisco Secure Firewall Management Center, 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.

Scoring

CVSS
8.1 (v3.1)
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-326
Assigned by
psirt@cisco.com

Dates

Published
2020-10-21
Last modified
2026-08-11
Sources
NVD

Affected products

  • Cisco Secure Firewall Management Center- 6.6.1
  • Cisco Secure Firewall Threat Defense- 6.6.1

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

References