The document discusses a critical vulnerability in Microsoft Exchange Server that could allow an attacker to remotely execute code on the target system. The vulnerability, tracked as CVE-2021-42321, affects multiple versions of Exchange Server and could be exploited by an attacker to take control of the system. To exploit this vulnerability, an attacker needs to send a specially crafted email to the target server, which can lead to arbitrary code execution
The document provides recommendations for mitigation, including patching the affected systems to the latest versions and blocking external access to the Exchange Control Panel. It is crucial for organizations using Microsoft Exchange Server to apply the necessary patches and follow the recommended security measures to protect their systems from potential attacks. https://www.cert.ssi.gouv.fr/pdf/CERTFR-2024-AVI-0366.pdf