The Federal Bureau of Investigation (FBI), CISA, and Coast Guard Cyber Command (CGCYBER) have released a Joint Cybersecurity Advisory (CSA) detailing the active exploitation of an authentication bypass vulnerability (CVE-2021-40539) in Zoho ManageEngine ADSelfService Plus—a self-service password management and single sign-on solution. The FBI, CISA, and CGCYBER assess that advanced persistent threat (APT) cyber actors are likely among those exploiting the vulnerability. The exploitation of this vulnerability poses a serious risk to critical infrastructure companies, U.S.-cleared defense contractors, academic institutions, and other entities that use the software.
CISA strongly encourages users and administrators to review Joint FBI-CISA-CGCYBER CSA: APT Actors Exploiting Newly Identified Vulnerability in ManageEngine ADSelfService Plus and immediately implement the recommended mitigations, which include updating to ManageEngine ADSelfService Plus build 6114.