Distributed enterprise systems have become essential for modern organizations, enabling seamless data sharing, scalability, and collaborative operations across geographically dispersed environments. However, the distributed nature of these systems introduces significant security challenges that can compromise data integrity, confidentiality, and system availability. This study examines the major security issues associated with distributed enterprise systems, including unauthorized access, data breaches, insecure communication channels, insider threats, and vulnerabilities in cloud and network infrastructures. It further explores the impact of emerging technologies such as cloud computing, microservices, and the Internet of Things (IoT), which expand the attack surface and increase system complexity. The paper discusses various security mechanisms and strategies, including encryption techniques, authentication and authorization protocols, intrusion detection systems, and secure API management, to mitigate these risks. Additionally, it highlights the importance of governance frameworks, compliance standards, and risk management practices in ensuring system security. The study concludes by emphasizing the need for a multi-layered security approach and continuous monitoring to safeguard distributed enterprise environments against evolving cyber threats.