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CVE-2020-3565

MEDIUMCVSS 5.8/10EPSS 0.93%

Last modified

CVE-2020-3565 is a medium-severity vulnerability rated 5.8/10 on the CVSS scale. 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. EPSS estimates a 0.93% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
5.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

EPSS Probability
0.93%

55.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoFirepower Threat Defense< 6.4.0.8
CiscoFirepower Threat Defense>= 6.5.0, < 6.5.0.4
CiscoFirepower Threat Defense>= 6.5.0.5, < 6.6.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is 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.
How severe is CVE-2020-3565?
CVE-2020-3565 has a CVSS score of 5.8/10 (MEDIUM severity). The EPSS model estimates a 0.93% probability of exploitation in the next 30 days.
How do I fix CVE-2020-3565?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-3565?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST