CVE-2021-34790
MediumCVSS 4.7Exploitation Probability (EPSS)
Elevated risk63th percentile - higher than 63% of all known CVEs
Summary
Multiple vulnerabilities in the Application Level Gateway (ALG) for the Network Address Translation (NAT) feature of Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass the ALG and open unauthorized connections with a host behind the ALG. These vulnerabilities are publicly known as NAT Slipstreaming.
Risk Assessment
An attacker could bypass ALG protections and gain access to internal hosts, potentially leading to unauthorized access to network resources and network integrity compromise.
Recommendation
It is recommended to upgrade ASA/FTD software to patched versions and implement additional traffic filtering mechanisms.
Original NVD description (English source)
Multiple vulnerabilities in the Application Level Gateway (ALG) for the Network Address Translation (NAT) feature of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass the ALG and open unauthorized connections with a host located behind the ALG. For more information about these vulnerabilities, see the Details section of this advisory. Note: These vulnerabilities have been publicly discussed as NAT Slipstreaming.