F-Secure Software Updater 2.20, as distributed in several F-Secure products, downloads installation packages over plain http and does not perform file integrity validation after download. Man-in-the-middle attackers can replace the file with their own executable which will be executed under the SYSTEM account. Note that when Software Updater is configured to install updates automatically, it checks if the downloaded file is digitally signed by default, but does not check the author of the signature. When running in manual mode (default), no signature check is performed.
Source: CVE-2017-6466 (software_updater)