UPDATE: The original post may not have provided full clarity that CVE-2021-44207 (USAHerds) had a patch developed by Acclaim Systems for applicable deployments on or around Nov. 15, 2021. Mandiant cannot speak to the affected builds, deployment, adoption, or other technical factors of this vulnerability patch beyond its availability.
In May 2021 Mandiant responded to an APT41 intrusion targeting a United States state government computer network. This was just the beginning of Mandiant’s insight into a persistent months-long campaign conducted by APT41 using vulnerable Internet facing web applications as their initial foothold into networks of interest. APT41 is a prolific Chinese state-sponsored espionage group known to target organizations in both the public and private sectors and also conducts financially motivated activity for personal gain.