CVE-2020-3549: Cisco Firepower Management Center Software and Firepower Threat Defense Software sftunnel Pass the Hash Vulnerability

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-10-21 · updated 2026-08-11
Weakness: CWE-326

Description

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.

Affected products

Cisco Firepower Management Center: before 6.6.1 — fixed in 6.6.1
Cisco Firepower Threat Defense Software: before 6.6.1 — fixed in 6.6.1

How to fix

Upgrade to a fixed version: Cisco Firepower Management Center 6.6.1; Cisco Firepower Threat Defense Software 6.6.1. Check the vendor advisory for mitigations.

References

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