CVE-2021-43074: 
FortiOS vulnerability analysis and mitigation

An improper verification of cryptographic signature vulnerability (CVE-2021-43074) was discovered in multiple Fortinet products. The vulnerability was internally discovered and reported by Giuseppe Cocomazzi of Fortinet Product Security team and was publicly disclosed on February 16, 2023. The affected products include various versions of FortiWeb, FortiOS, FortiSwitch, and FortiProxy. This vulnerability has been assigned a CVSS v3.1 base score of 4.3 (Medium severity) (NVD, Fortiguard).

The vulnerability is classified as CWE-347 (Improper Verification of Cryptographic Signature). It affects the session management cookie encryption implementation in the affected products. The vulnerability has been assigned a CVSS vector of CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N, indicating network accessibility, low attack complexity, and requiring low privileges (NVD).

If successfully exploited, this vulnerability allows an attacker to decrypt portions of the administrative session management cookie if they are able to intercept it. The impact is limited to information disclosure with no direct impact on integrity or availability of the system (Fortiguard).

Fortinet has released patches for all affected products. Users are advised to upgrade to the following versions: FortiOS version 7.0.4 or above, FortiOS version 6.4.9 or above, FortiWeb version 7.0.0 or above, FortiWeb version 6.3.17 or above, FortiProxy version 7.0.2 or above, FortiProxy version 2.0.8 or above, FortiSwitch version 7.2.0 or above, FortiSwitch version 7.0.4 or above, or FortiSwitch version 6.4.11 or above (Fortiguard).