CVE-2020-3565
MediumCVSS 5.8Exploitation Probability (EPSS)
Elevated risk58th percentile - higher than 58% of all known CVEs
Summary
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 Policies. This is because TCP Intercept is invoked when the embryonic connection limit is reached, causing the detection engine to process packets incorrectly. An attacker could send a crafted traffic stream to match an incorrect policy, potentially forwarding traffic that should be dropped or vice versa.
Risk Assessment
The risk is the potential to bypass security policies and incorrectly forward or drop traffic, potentially leading to network integrity issues.
Recommendation
It is recommended to update FTD software to a patched version and review TCP Intercept and policy configurations.
Original NVD description (English source)
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.