CISA and the US Coast Guard Cyber Command are releasing this joint Cybersecurity Advisory to warn network defenders that cyber threat actors, including state-sponsored APT actors, have continued to exploit CVE-2021-44228 (Log4Shell) in VMware Horizon and Unified Access Gateway servers to obtain initial access to organizations that did not apply available patches or workarounds.

AA22-174A Alert, Technical Details, and Mitigations

Malware Analysis Report 10382254-1 stix

Malware Analysis Report 10382580-1 stix

CISA’s Apache Log4j Vulnerability Guidance webpage

Joint CSA Mitigating Log4Shell and Other Log4j-Related Vulnerabilities

CISA’s database of known vulnerable services on the CISA GitHub page

See National Security Agency (NSA) and Australian Signals Directorate (ASD) guidance Block and Defend Web Shell Malware for additional guidance on hardening internet-facing systems.

All organizations should report incidents and anomalous activity to CISA’s 24/7 Operations Center at [email protected] or (888) 282-0870 and to the FBI via your local FBI field office or the FBI’s 24/7 CyWatch at (855) 292-3937 or [email protected].