From cisa.gov
The Cybersecurity and Infrastructure Security Agency (CISA) and United States Coast Guard Cyber Command (CGCYBER) are releasing this joint Cybersecurity Advisory (CSA) to warn network defenders that cyber threat actors, including state-sponsored advanced persistent threat (APT) actors, have continued to exploit CVE-2021-44228 (Log4Shell) in VMware Horizon® and Unified Access Gateway (UAG) servers to obtain initial access to organizations that did not apply available patches or workarounds.
Since December 2021, multiple threat actor groups have exploited Log4Shell on unpatched, public-facing VMware Horizon and UAG servers. As part of this exploitation, suspected APT actors implanted loader malware on compromised systems with embedded executables enabling remote command and control (C2). In one confirmed compromise, these APT actors were able to move laterally inside the network, gain access to a disaster recovery network, and collect and exfiltrate sensitive data.