Auth bypass in Cisco Firepower Threat Defense Software

CVE-2020-3565

A vulnerability in the TCP Intercept functionality of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured Access Control Policies (including Geolocation) and Service Polices on an affected system. The vulnerability exists because TCP Intercept is invoked when the embryonic connection limit is reached, which can cause the underlying detection engine to process the packet incorrectly. An attacker could exploit this vulnerability by sending a crafted stream of traffic that matches a policy on which TCP Intercept is configured. A successful exploit could allow the attacker to match on an incorrect policy, which could allow the traffic to be forwarded when it should be dropped. In addition, the traffic could incorrectly be dropped.

EPSS: 0.009 (57.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2020-3565?
CVE-2020-3565 is a medium-severity vulnerability in Cisco Firepower Threat Defense Software, classified under Improper Access Control. CVSS score: 5.8/10. Published 2020-10-21.
How severe is CVE-2020-3565?
Medium severity. CVSS v3 base score is 5.8 out of 10.