Over 3,000 internet-exposed Apache ActiveMQ servers are at risk due to a critical remote code execution (RCE) vulnerability, as reported on October 27, 2023. Apache ActiveMQ is a widely used open-source message broker that facilitates communication between clients and servers, supporting multiple languages and protocols.
The vulnerability in question, labeled CVE-2023-46604 with a high CVSS v3 score of 10.0, allows attackers to execute arbitrary shell commands by exploiting serialized class types within the OpenWire protocol. To address this threat, security fixes were released on the same day, including versions 5.15.16, 5.16.7, 5.17.6, and 5.18.3, which are highly recommended for users to upgrade to.
In a concerning development, researchers from the threat monitoring service ShadowServer discovered a total of 7,249 servers with ActiveMQ services accessible online. Of these, 3,329 servers were found to run versions of ActiveMQ that are vulnerable to CVE-2023-46604, rendering them exposed to remote code execution. The majority of these vulnerable servers, approximately 1,400 of them, are located in China, while the United States follows with 530, and Germany with 153. Other countries, including India, the Netherlands, Russia, France, and South Korea, also had approximately 100 exposed servers each.
The exploitation of CVE-2023-46604 is highly concerning given Apache ActiveMQ’s role as a message broker in enterprise environments. Attackers exploiting this vulnerability could intercept messages, disrupt workflows, steal data, and potentially move laterally within networks.
It is crucial for organizations to apply the provided security updates promptly, especially since technical details on how to exploit this vulnerability are publicly available, making a swift response time-sensitive.